AN INTRODUCTION TO
介绍
Transport Phenomena in Materials Engineering
材料工程中的传输现象
S E C O N D E D I T I O N
第二版
DAVID R. GASKELL
大卫·R·加斯凯尔
AN INTRODUCTION TO
介绍
Transport Phenomena in Materials Engineering
材料工程中的传输现象
S E C O N D E D I T I O N
第二版
DAVID R. GASKELL
大卫·R·加斯凯尔
An Introduction to TRANSPORT PHENOMENA
运输现象导论
in
在
MATERIALS ENGINEERING,
材料工程,
2nd Edition
第二版
An Introduction to TRANSPORT PHENOMENA
in
在
MATERIALS ENGINEERING,
材料工程,
2nd Edition
第二版
DAVID R. GASKELL
大卫·R·加斯凯尔
MOMENTUM PRESS, LLC, NEW JERSEY
动量出版社,有限责任公司,新泽西
An Introduction to Transport Phenomena in Materials Engineering, 2nd Edition
材料工程中的传输现象导论(第二版)
Copyright © Momentum Press®, LLC, 2013
版权 © Momentum Press®, LLC, 2013
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means—electronic, mechanical, photocopy, recording or any other—except for brief quotations, not to exceed 400 words, without the prior permission of the publisher.
版权所有。未经出版商事先许可,任何部分不得以任何形式或通过任何手段(电子、机械、复印、录音或其他)复制、存储在检索系统中或传输——除非是简短引用,不超过 400 字。
First edition published by Macmillan Publishing Company, New York;
第一版由麦克米伦出版公司出版,纽约;
Maxwell Macmillan Canada, Toronto; Maxwell Macmillan International in 1991
麦克斯韦·麦克米兰加拿大,多伦多;1991 年麦克斯韦·麦克米兰国际
Second edition published in 2012 by Momentum Press®, LLC
2012 年由 Momentum Press®,LLC 出版的第二版
222 East 46th Street New York, NY 10017
纽约,东 46 街 222 号,邮政编码 10017
ISBN-13: 978-1-60650-355-3 (hard cover, case bound) ISBN-10: 1-60650-355-3 (hard cover, case bound) ISBN-13: 978-1-60650-357-7 (e-book)
ISBN-13: 978-1-60650-355-3(精装,盒装) ISBN-10: 1-60650-355-3(精装,盒装) ISBN-13: 978-1-60650-357-7(电子书)
ISBN-10: 1-60650-357-X (e-book) DOI: 10.5643/9781606503577
ISBN-10: 1-60650-357-X (电子书) DOI: 10.5643/9781606503577
Cover design by Jonathan Pennell 10 9 8 7 6 5 4 3 2 1
封面设计:Jonathan Pennel 10 9 8 7 6 5 4 3 2 1
Printed in the United States of America
在美国印刷
For Ivy Jean
给艾薇·简
Preface to the Second Edition
第二版前言
The first edition of this textbook contained a large number of typographical errors. In this, the second edition, a serious attempt has been made to correct these errors. The major difference, however, between the first and this edition is that this edition contains an additional chapter, Chapter 12, titled “Boiling and Condensation.” The material presented in this chapter is particularly important in view of the current interest in Renewal Energy Resources involving such devices as windmills and solar panels. Developments in this field require a thorough familiarity with the phenomena and mechanisms of boiling and condensation.
本教材的第一版包含大量排版错误。在这一版,即第二版中,已认真尝试纠正这些错误。然而,第一版与这一版之间的主要区别在于这一版包含了一个附加章节,第 12 章,标题为“蒸发与冷凝”。考虑到当前对可再生能源资源的兴趣,涉及风车和太阳能电池板等设备,本章所呈现的材料尤为重要。该领域的发展需要对蒸发和冷凝的现象和机制有透彻的了解。
vii
ix
x Preface
List of Symbols xvii
符号列表 xvii
Engineering Units and Pressure in Static Fluids 1
静态流体中的工程单位和压力 1
Origins of Engineering Units 1
工程单位的起源 1
Concept of Pressure 5
压力的概念 5
Measurement of Pressure 11
压力测量 11
Pressure in Incompressible Fluids 15
不可压缩流体中的压力 15
Buoyancy 21
浮力 21
Summary 26
摘要 26
Problems 27
问题 27
Momentum Transport and Laminar Flow of Newtonian Fluids 30
牛顿流体的动量传输和层流
Introduction 30
介绍 30
Newton’s Lax of Viscosity 32
牛顿的粘度定律 32
Conservation of Momentum in Steady-State Flow 36
稳态流动中的动量守恒 36
Fluid Flow Between Two Flat Parallel Plates 40
两个平行平板之间的流体流动 40
Fluid Flow down in Inclined Plane 48
倾斜平面上的流体流动 48
Fluid Flow in a Vertical Cylindrical Tube 53
垂直圆柱管中的流体流动 53
Capillary Flowmeter 65
毛细管流量计 65
xi
xii Contents
Fluid Flow in an Annulus 69
环形间隙中的流体流动 69
Mean Residence Time 76
平均停留时间 76
Calculation of Viscosity from the Kinetic Theory of Gases 78
气体动理论中的粘度计算 78
Viscosities of Liquid Metals 90
液态金属的粘度 90
Equations
Equation of Continuity 102
连续性方程 102
Conservation of Momentum 104
动量守恒 104
Navier-Stokes Equation for Fluids of Constant Density and Viscosity 108
常密度和粘度流体的纳维-斯托克斯方程 108
Fluid Flow over a Horizontal Flat Plane 115
水平平面上的流体流动 115
Approximate Integral Method in Obtaining Boundary Layer Thickness 117
在获得边界层厚度中的近似积分法 117
Creeping Flow past a Sphere 125
球体周围的爬行流动 125
Graphical Representation of Fluid Flow 139
流体流动的图形表示 139
Friction Factor and Turbulent Flow in Cylindrical Pipes 141
圆管中的摩擦因子和湍流 141
Flow Over a Flat Plate 153
平板上的流动 153
Flow Past a Submerged Sphere 160
沉浸球体周围的流动 160
Flow Past a Submerged Cylinder 163
沉浸圆柱体周围的流动 163
Flow Through Packed Beds 167
流经填充床 167
Mechanical Energy Balance and Its Application to Fluid Flow 185
机械能平衡及其在流体流动中的应用 185
Contents
Friction Loss, Ef 188
摩擦损失,Ef 188
Influence of Bends, Fittings, and Changes in the
弯头、配件和变化的影响
Fluid Flow in an Open Channel 205
开放渠道中的流体流动 205
Drainage from a Vessel 207
从容器排水 207
Emptying a Vessel by Discharge Through an Orifice 209
通过孔口排放排空容器 209
Drainage of a Vessel Using a Drainage Tube 213
使用排水管排放容器的排水 213
Emptying a Vessel by Drainage Through a Drainage Tube 215
通过排水管排空容器 215
Bernoulli Equation for Flow of Compressible Fluids 219
可压缩流体流动的伯努利方程 219
Transport of Heat by Conduction 235
通过导热传输热量 235
Fourier’s Law and Newton’s Law 236
傅里叶定律和牛顿定律 236
Conduction in Heat Sources 256
热源中的传导 256
Thermal Conductivity and the Kinetic Theory of Gases 267
热导率与气体动理论 267
General Heat Conduction Equation 274
一般热传导方程 274
Conduction of Heat at Steady State in Two Dimensions 278
二维稳态热传导 278
Transport of Heat by Convection 295
对流传热 295
Heat Transfer by Forced Convection from a Horizontal Flat Plate at a Uniform Constant Temperature 295
水平平板在均匀恒定温度 295 下的强制对流热传递
Heat Transfer from a Horizontal Flat Plate with Uniform Heat Flux Along the Plate 315
沿板的均匀热流从水平平板的热传递 315
Heat Transfer During Fluid Flow in Cylindrical Pipes 317
圆管内流体流动中的热传递 317
Energy Balance in Heat Transfer by Convection Between a Cylindrical Pipe and a Flowing Fluid 322
圆柱管与流动流体之间的对流热传递中的能量平衡 322
Heat Transfer by Forced Convection from Horizontal Cylinders 331
水平圆柱体的强制对流热传递 331
Heat Transfer by Forced Convection from a Sphere 334
球体的强制对流热传递 334
General Energy Equation 335
一般能量方程 335
Heat Transfer from a Vertical Plate by Natural Convection 346
通过自然对流从垂直板的热传递 346
xiv Contents
Heat Transfer from Cylinders by Natural Convection 358
通过自然对流从圆柱体的热传递 358
Transient Heat Flow 365
瞬态热流 365
Lumped Capacitance Method; Newtonian Cooling 365
集中电容法;牛顿冷却 365
Non-Newtonian Cooling in Semi-infinite Systems 373
半无限系统中的非牛顿冷却 373
Non-Newtonian Cooling in a One-Dimensional Finite Systems 382
一维有限系统中的非牛顿冷却 382
Non-Newtonian Cooling in a Two-Dimensional Finite Systems 394
二维有限系统中的非牛顿冷却 394
Solidification of Metal Castings 401
金属铸件的固化 401
Heat Transport by Thermal Radiation 421
热辐射传输 421
Intensity and Emissive Power 423
强度和发射功率 423
Blackbody Radiation 427
黑体辐射 427
Absorptivity, Reflectivity, and Transmissivity 436
吸收率、反射率和透射率 436
Kirchho$’s Law and the Hohlraum 437
基尔霍夫定律与霍尔 raum 437
Radiation Exchange Between Surfaces 439
表面之间的辐射交换 439
Radiation Exchange Between Blackbodies 450
黑体之间的辐射交换 450
Radiation Exchange Between Di$use-Gray Surfaces 453
扩散灰表面之间的辐射交换 453
Reradiating Surface 463
重新辐射表面 463
Heat Transfer from a Surface by Convection and Radiation 466
通过对流和辐射从表面传递的热量 466
Mass Transport by Di$usion in the Solid State 476
固态中的扩散质量传输 476
Atomic Di$usion as a Random-Walk Process 476
原子扩散作为随机游走过程 476
Contents
One-Dimensional Non-Steady-State Di$usion in a Solid; Fick ’s Second Law of Di$usion 483
一维非稳态扩散在固体中;菲克第二扩散定律 483
Infinite Di$usion Couple 489
无限扩散耦合 489
One-Dimensional Di$usion in a Semi-infinite System Involving a Change of Phase 491
半无限系统中涉及相变的一维扩散 491
Steady-State Di$usion Through a Composite Wall 498
复合墙的稳态扩散 498
Di$usion in Substitutional Solid Solutions 502
替代固溶体中的扩散 502
Darken’s Analysis 502
Darken 的分析 502
Self-Di$usion Coefficient 506
自扩散系数 506
Measurement of the Interdifussion Coefficient: Boltzmann–Matano Analysis 510
扩散系数的测量:Boltzmann–Matano 分析 510
Influence of Temperature on the Di$usion Coefficient 514
温度对扩散系数的影响 514
Mass Transport in Fluids 522
流体中的质量传输 522
Mass and Molar Fluxes in a Fluid 522
流体中的质量和摩尔通量 522
Equations of Di$usion with Convection in a Binary Mixture A–B 524
二元混合物 A–B 中的扩散与对流方程 524
One-Dimensional Transport in a Binary Mixture of Ideal Gases 527
理想气体二元混合物中的一维传输 527
Equimolar Counterdi$usion 528
等摩尔反向扩散 528
One-Dimensional Steady-State Di$usion of Gas A Through Stationary Gas B 529
气体 A 在静止气体 B 中的一维稳态扩散 529
Sublimation of a Sphere into a Stationary Gas 536
球体在静止气体中的升华 536
Catalytic Surface Reactions 539
催化表面反应 539
Di$usion and Chemical Reaction in Stagnant Film 542
静止薄膜中的扩散和化学反应 542
Mass Transfer at Large Fluxes and Large Concentrations 547
大流量和高浓度下的质量传递 547
Influence of Mass Transport on Heat Transfer in Stagnant Film 550
静止薄膜中质量传输对热传递的影响 550
Di$usion into a Falling Film of Liquid 553
液体下落薄膜中的扩散 553
Di$usion and the Kinetic Theory of Gases 560
扩散与气体的动理论 560
Mass Transfer Coefficient and Concentration Boundary Layer on a Flat Plate 569
平板上的质量传递系数和浓度边界层 569
Approximate Integral Method 573
近似积分法 573
Mass Transfer by Free Convection 583
自由对流的质量传递 583
Simultaneous Heat and Mass Transfer: Evaporate Cooling 586
同时的热量和质量传递:蒸发冷却 586
Chemical Reaction and Mass Transfer: Mixed Control 589
化学反应与质量传递:混合控制 589
Dissolution of Pure Metal A in Liquid B: Mixed Control 593
纯金属 A 在液体 B 中的溶解:混合控制 593
xvi Contents
Condensation and Boiling 601
凝结与沸腾 601
Dimensionless Parameters in Boiling and Condensation 602
无量纲参数在沸腾和冷凝中的应用 602
Pool Boiling Correlations 606
池沸腾相关性 606
Appendix A Elementary and Derived SI Units
附录 A 基本和衍生 SI 单位
Appendix B Prefixes and Symbols for Multiples and Submultiples of SI Units 617
附录 B SI 单位的倍数和分数的前缀和符号 617
Appendix C Conversion from British and U.S. Units to SI Units 618
附录 C 从英制和美制单位转换为国际单位制 618
Appendix D Properties of Solid Metals 620
附录 D 固体金属的性质 620
Appendix E Properties of Nonmetallic Solids 623
附录 E 非金属固体的性质 623
Appendix F Properties of Gases at 1 Atm Pressure 627
附录 F 1 个大气压下气体的性质 627
Appendix G Properties of Saturated Liquids 635
附录 G 饱和液体的性质 635
Appendix H Properties of Liquid Metals 639
附录 H 液态金属的性质 639
Recommended Readings 642
推荐阅读 642
xvii
十七
xviii List of Symbols
List of Symbols xix
xx List of Symbols
Condensation and Boiling
凝结与沸腾
Introduction
介绍
Evaporation is a process that occurs when a liquid, maintained at a constant temperature, exerts a partial vapor pressure in the gas phase, in contact with the liquid, which is less than the saturated vapor pressure of the liquid at the same temperature. At any finite temperature, the atoms or molecules in the liquid are in constant motion, vibrating in a cage of adjacent atoms or molecules as a result of the attractive and repulsive forces on the central atom by its neighbors. The magnitude of this agitation, which is determined by the temperature of the liquid, increases with increasing temperature. Thus, the atoms in the layer of liquid in contact with the gas phase can attain increases in energy which are greater than the activation energy required for evaporation, in which case the atom is transferred from the liquid phase to the gas phase. This process, which is called evaporation, continues until, thereby, the partial pressure of the component in the gas phase reaches its saturated vapor pressure at the temperature of interest.
蒸发是一个过程,当液体在恒定温度下,施加于与液体接触的气相中的部分蒸气压小于该温度下液体的饱和蒸气压时,就会发生蒸发。在任何有限温度下,液体中的原子或分子都在不断运动,由于邻近原子或分子对中心原子的吸引和排斥力,导致它们在一个相邻原子或分子的笼子中振动。这种激动的大小由液体的温度决定,随着温度的升高而增加。因此,接触气相的液体层中的原子可以获得超过蒸发所需的活化能的能量,在这种情况下,原子从液相转移到气相。这个被称为蒸发的过程持续进行,直到气相中该组分的部分压力达到其在所关注温度下的饱和蒸气压。
When a liquid is contained in a vessel, its surface tension prevents it from completely filling the invariable imperfections that occur on the inner surface of the vessel. Thus, small pockets of air or nitrogen are trapped in these imperfections, and atoms on the liquid side of the interface, when acquiring an increase in energy greater than the activation energy for evaporation transfer into the trapped bubble. This process continues until the partial pressure of the component in the bubble reaches the saturation pressure. This partial pressure increases with increasing temperature until it reaches the total pressure of the gas in contact with the liquid, which is, by definition, the boiling temperature of the liquid. During the period during which the liquid is being heated, the partial pressure of the component in the trapped bubble increases, as a consequence of which, the volume of the bubble increases. At the boiling
当液体被容器包围时,其表面张力阻止液体完全填充容器内表面上出现的不变缺陷。因此,空气或氮气的小口袋被困在这些缺陷中,当界面液体侧的原子获得的能量增加超过蒸发转移的活化能时,就会转移到被困的气泡中。这个过程持续进行,直到气泡中成分的分压达到饱和压力。随着温度的升高,这个分压增加,直到达到与液体接触的气体的总压力,这在定义上是液体的沸点。在液体加热的过程中,被困气泡中成分的分压增加,因此气泡的体积也增加。 在沸腾时
602 Condensation and Boiling
temperature of the liquid, the geometry of the bubble makes it unstable and it detaches from the imperfection and, due the difference between densities of the liquid and vapor phases, rises to the free surface of the liquid where it is ejected into the gas. The decreasing hydrostatic pressure on the rising bubble causes it to increase in volume. When the bubble detaches from the imperfection, the volume of gas in the imperfection decreases, and the growth process begins again. This process is the same as that when a bottle of soft drink, carbonated with CO2 at high pressure, is opened and poured into a drinking glass. The rapid nucleation, growth, and release of the bubbles at the surface imperfections can be seen through the glass. When the liquid is a single component, boiling occurs at a fixed temperature, and the rate of boiling increases with increasing rate of transfer of heat to the liquid.
液体的温度,气泡的几何形状使其不稳定,并且它从缺陷上脱离,由于液相和气相之间的密度差,气泡上升到液体的自由表面,在那里被喷射到气体中。上升气泡上减少的静水压力导致其体积增加。当气泡从缺陷上脱离时,缺陷中的气体体积减少,生长过程再次开始。这个过程与打开高压二氧化碳(CO 2 )碳酸饮料瓶并倒入饮用杯时的过程相同。通过玻璃可以看到表面缺陷处气泡的快速成核、增长和释放。当液体是单一组分时,沸腾发生在固定温度下,沸腾速率随着传递给液体的热量增加而增加。
Condensation occurs when an atom or molecule in the gas phase strikes the free surface of the liquid and is captured. The individual atoms or molecules in the gas phase have velocities within a spectrum of velocities, the extremes of which are determined by the temperature of the gas and the atomic or molecular weights of particles in the gas. Particles with a high enough velocity, and hence high enough kinetic energy, are captured by the liquid and this process is called condensation. Particles with less than this velocity undergo elastic collisions with the free surface and bounce back into the gas phase. When the partial pressure of the component in the gas phase equals its saturated vapor pressure, the rates of evaporation and condensation are equal and phase equilibrium occurs.
当气相中的原子或分子撞击液体的自由表面并被捕获时,就会发生凝结。气相中的单个原子或分子具有一系列速度,这些速度的极值由气体的温度和气体中粒子的原子或分子量决定。具有足够高速度(因此具有足够高动能)的粒子被液体捕获,这个过程称为凝结。速度低于这个值的粒子与自由表面发生弹性碰撞,并反弹回气相。当气相中组分的分压等于其饱和蒸气压时,蒸发和凝结的速率相等,发生相平衡。
A knowledge of the mechanisms of the transport of heat between a solid surface and the fluid with which it is contact is important in the heat treatment of ferrous alloys. Time-Temperature-Transformation (T-T-T) Diagrams for ferrous alloys show the influence of cooling rates (quenching rates) on the microstructure obtained at room temperature. In the case of plain carbon steels of the eutectoid composition, increasing the cooling rate causes microstructures to vary in the range of coarse pearlite, fine pearlite, upper bainite, lower bainite. If the cooling rate is rapid enough that the variation of temperature with time misses the nose of the T-T-T curve, austenite is retained until the Ms (martensite start) temperature is reached. At this point, with further cooling, the face-centered cubic γ phase transforms, by diffusionless shear, to the body-centered tetragonal martensite phase. This transformation continues until the temperature reaches the Mf (martensite finish) temperature. The change in molar volume accompanying this phase change gives rise to high shear stresses at the phase boundaries, which causes the martensite phase to be brittle. This brittleness is removed by tempering the alloy at a temperature high enough to allow some nucleation and precipitation of cementite from the martensite.
固体表面与其接触的流体之间热量传输机制的知识在铁合金的热处理过程中非常重要。铁合金的时间-温度-转变(T-T-T)图显示了冷却速率(淬火速率)对室温下获得的微观结构的影响。在共析成分的普通碳钢中,增加冷却速率会导致微观结构在粗珠光体、细珠光体、上贝氏体和下贝氏体的范围内变化。如果冷却速率足够快,以至于温度随时间的变化错过了 T-T-T 曲线的鼻部,奥氏体会保持直到达到 Ms(马氏体开始)温度。在这一点上,随着进一步冷却,面心立方γ相通过无扩散剪切转变为体心四方马氏体相。这一转变持续到温度达到 M f (马氏体结束)温度。伴随这一相变的摩尔体积变化在相界面产生高剪切应力,导致马氏体相变得脆弱。 这种脆性通过在足够高的温度下对合金进行回火来消除,以允许一些水泥石的成核和从马氏体中沉淀。
Dimensionless Parameters in Boiling and Condensation
无量纲参数在沸腾和冷凝中
For both the boiling and the condensation processes, the convection coefficient could depend on the difference between the surface and saturation temperatures,
对于沸腾和冷凝过程,传热系数可能依赖于表面温度和饱和温度之间的差异,
Te = Ts Tsat, the body force caused by the difference between the densities of the
T e = T s T sat ,由密度差引起的体力
liquid and vapor phases, g ( ρ1 ρv), the latent heat of evaporation Hevap, the surface
液体和蒸气相,g ( ρ 1 ρ v ), 蒸发潜热 H evap , 表面
Modes of Boiling 603
沸腾的模式 603
tension σ, a characteristic length L and the thermophysical properties of the liquid or vapor, density , molar heat capacity cp, thermal conductivity k and viscosity η; that is,
张力 σ、特征长度 L 和液体或蒸气的热物理性质,密度 、摩尔热容 c p 、热导率 k 和粘度 η;也就是说,
h = h[T, g (ρl – ρv), Hevap , σ, L, ρ, cp, k, η]
Straightforward dimensionless gives the relationship
简单的无量纲给出了关系
(12.1)
hL f ρ g( ρl ρv ) L 3 ,
hL = f [ρ g(ρ - ρ v ) L 3 ,
cp T , ηcp
, g ( ρl
ρv) 2L
(12.2)
k η2
Hevap k
σ
or, defining the dimensionless groups,
或者,定义无量纲组,
Nu
f ρg( ρl ρv ) L3
Ja , Pr, Bo (12.3)
L η 2
The Prandtl number, Pr hcp /k, was defined on p. 298 and the Nusselt number, Nu hL/k, was defined on P. 299. The Jacob number, Ja, which is the ratio of the maximum sensible energy absorbed by the liquid (or vapor) to the latent heat absorbed by the liquid (or vapor) during condensation (or boiling) is given by
普朗特数,Pr hc p /k,在第 298 页定义,努塞尔数,Nu hL/k,在第 299 页定义。雅各布数,Ja,是液体(或蒸气)在凝结(或蒸发)过程中吸收的最大显热与液体(或蒸气)吸收的潜热之比。
Ja
cp (Ts Tsat )
Hevap
(12.4)
and the Bond number, Bo, which is the ratio of the gravitational body force to the surface tension force, is given by
和邦德数 Bo,它是重力体力与表面张力力的比率,表示为
Bo
g ( ρf
ρv )L 2
σ
(12.5)
Modes of Boiling
沸腾的模式
The term boiling is used to describe the process of evaporation at the free surface of a liquid. The modes of boiling are shown graphically on a log-log plot of the variation of the heat flux from the solid surface to the liquid, q"s , with the excess temperature,
“沸腾”一词用于描述液体自由表面上的蒸发过程。沸腾的模式在固体表面到液体的热流量 q" s 与过剩温度的对数-对数图上以图形方式显示。
Te = Ts Tsat, where Ts is the temperature of the surface and Tsat is the temperature
T e = T s T sat ,其中 T s 是表面的温度,T sat 是温度
at which the partial pressure of the component in the gas phase is equal to the saturated vapor pressure. Heat is transferred from solid surface to the liquid according to Newton’s Law as
在气相中该组分的分压等于饱和蒸气压时。根据牛顿定律,热量从固体表面传递到液体。
qs h (Ts
Tsat ) hTe
(12.6)
The process is characterized by the formation of bubbles of vapor, which grow and, subsequently, detach from the surface.
该过程的特点是形成蒸汽气泡,这些气泡不断增大,随后从表面脱离。
The various regimes of boiling are identified in the boiling curve, shown as Fig. 12.1, which is drawn for water at one atmosphere pressure. Eq. (12.6) shows that
沸腾的各种状态在沸腾曲线中被识别,如图 12.1 所示,该图是为在一个大气压下的水绘制的。方程(12.6)显示出
604 Condensation and Boiling
604 凝结与沸腾
Free
免费
Boiling Regimes Nucleate
沸腾状态成核
Transition
Film
电影
107
convection isolated
对流隔离
jets and columns
喷气机和柱子
106
9”max
P
105
point, 9” min
104
∆Te,A ∆Te,B
∆Te,C
∆Te,
103
1
5 10
30
∆Te = Ts – Tsat
120
Centigrade Degrees
摄氏度
1000
FIGURE 12.1 The boiling curve for water at 1 atm.
q"s depends on both the convection coefficient, h, and the excess temperature, Te.
q" s 依赖于对流系数 h 和过剩温度 T e 。
The various boiling regimes are delineated by their values of Te.
各种沸腾状态由它们的 T e 值划分。
Free Convection Boiling
自由对流沸腾
Free convection boiling occurs when Te Te, A ≈ 5 centigrade degrees. In this regime, the amount of vapor in contact with the liquid phase is not enough to cause boiling at the temperature at which the liquid exerts its saturated vapor pressure. As the excess temperature is increased, the formation of bubbles eventually begins, but
自由对流沸腾发生在 T e T e A ≈ 5 摄氏度。在这个状态下,与液相接触的蒸汽量不足以在液体施加其饱和蒸汽压力的温度下引起沸腾。随着过剩温度的增加,气泡的形成最终开始,但
Modes
at temperatures lower than the point A, termed the onset of nucleate boiling, ONB, fluid motion is determined mainly by free convection. According to whether the flow is laminar or turbulent, h varies with Te to the 1/4 or 1/3 power, respectively, in which
在低于点 A 的温度下,称为成核沸腾的开始(ONB),流体运动主要由自然对流决定。根据流动是层流还是湍流,h 分别与ΔT 的 0 次方、1/4 次方或 1/3 次方变化。
case q"s varies with Te to the 5/4 or 4/3 power.
情况 q" s 随着 T e 变化至 5/4 或 4/3 次方。
Nucleate Boiling
成核沸腾
Nucleate boiling occurs in the range Te, A δ Te δ Te, C, where Te, C ≈ 30 centigrade degrees. Two flow regimes exist in this range. At lower temperatures in the region AB, isolated bubbles form at nucleation sites and separate from the surface, which, by causing significant mixing in the fluid adjacent to the surface, substantially increases both h and q"s . Most of the heat exchange is by direct transfer from the surface to the liquid in motion at the surface. As Τe is increased beyond Τe, B, more nucleation sites become active and the consequent increased formation of bubbles causes interference between, and coalescence of, the bubbles. In the region B — C the vapor escapes in columns, which eventually merge into slugs of vapor. Motion of the liquid near the surface is inhibited by interference between the densely populated bubbles. Point P in Fig. 12.1 is a point of inflection on the boiling curve at which h has a maximum value. At this point h begins to decrease with increasing Τe, although q"s , which is the product of h and Τe continues to increase. This situation arises because, for Τe Τe, P the relative increase in Τe exceeds the relative decrease in h. At the point C, however, the further increase in Τe is balanced by the decrease in h. The maximum heat flux, qs, C" = qmax", the critical heat flux, in water at atmospheric pressure exceeds 1 MW/m2. At this point, the amount of vapor formed makes it difficult for the liquid to continuously wet the surface.
核化沸腾发生在范围 T e A δ T e δ T e C ,其中 T e C ≈ 30 摄氏度。这个范围内存在两种流动状态。在 A−B 区域的较低温度下,孤立气泡在成核点形成并从表面分离,这通过在靠近表面的流体中造成显著混合,显著增加了 h 和 q" s 。大部分热交换是通过表面与表面上运动的液体之间的直接传递进行的。当 Τ e 超过 Τ e B 时,更多的成核点变得活跃,随之而来的气泡形成增加导致气泡之间的干扰和合并。在 B — C 区域,蒸汽以柱状形式逃逸,最终合并成蒸汽块。靠近表面的液体运动受到密集气泡之间干扰的抑制。图 12.1 中的点 P 是沸腾曲线上的一个拐点,在该点 h 达到最大值。在这一点上,h 开始随着 Τ e 的增加而减少,尽管 q" s ,即 h 和 Τ e 的乘积继续增加。 这种情况出现是因为,对于 Τ e Τ e P ,Τ e 的相对增加超过了 h 的相对减少。然而,在点 C,Τ e 的进一步增加被 h 的减少所平衡。在大气压力下,水的最大热流量 q s C " = q max ",临界热流量超过 1 MW/m2。在这一点上,形成的蒸汽量使得液体难以持续润湿表面。
Transition boiling
过渡沸腾
The region Τe,C Τe Τe, D, where Τe, D is called, transition boiling, film boiling or partial film boiling. The rate of formation of bubbles is now so rapid that a film of vapor begins to form on the surface. At any point on the surface, conditions may change from film to nucleate boiling, but the fraction of the total surface covered by the film increases with increasing Τe. Because the thermal conductivity of the vapor is much less than that of the liquid, h, and q"s , decrease with increasing Τe .
该区域 Τ e C Τ e Τ e D 被称为过渡沸腾、膜沸腾或部分膜沸腾。气泡的形成速率现在如此迅速,以至于在表面开始形成一层蒸汽膜。在表面的任何一点,条件可能会从膜沸腾变化为成核沸腾,但被膜覆盖的总表面比例随着 Τ e 的增加而增加。由于蒸汽的热导率远低于液体的热导率,h 和 q" s 随着 Τ e 的增加而降低。
Film Boiling
电影沸腾
Film boiling occurs in the range Τe Τe, D. At the point D on the boiling curve, referred to as the Leidenfrost point, the heat flux is a minimum, q"s , = q"min and the surface is completely covered with a film of vapor. Heat transfer from the surface to the liquid occurs by conduction through the vapor. With further increase in the surface temperature, radiation through the vapor film becomes significant and the heat flux increases with increasing Τe.
膜沸腾发生在范围 Τ e Τ e D 。在沸腾曲线的点 D,称为莱顿弗罗斯特点,热流密度达到最小值,q" s = q" min ,表面完全被蒸汽膜覆盖。热量通过蒸汽的导热从表面传递到液体。随着表面温度的进一步升高,蒸汽膜中的辐射变得显著,热流密度随着 Τ e 的增加而增加。
The preceding discussion concerns the condition in which the heat flux, q"s , is determined by the imposed value of Τe. The behavior is significantly different if the heat flux is the independent variable. Consider starting at some point P, shown in
前面的讨论涉及热流 q" s 由施加的 ΔΤ e 值决定的情况。如果热流是自变量,则行为会显著不同。考虑从某个点 P 开始,如图所示。
606 Condensation and Boiling
g”max
∆Te,C ∆Te,E
∆Te = Ts – Tsat
FIGURE 12.2 Onset of the boiling crisis.
图 12.2 沸腾危机的开始。
Fig. 12.2, and increasing the heat flux. The system moves, as before, up the boiling curve to the point C, but any attempt to further increase the heat flux causes the system to jump to the point E, which probably occurs at a temperature higher than the melting temperature of the solid, which, consequently, causes destruction of the solid. For this reason, point C is called the burnout point, and it is important that the value of the critical heat flux be known accurately, as it may be required that the system be operated at a heat flux which is close to the critical value, but which may not exceed the critical value. Applications involving controlling q’ include nuclear reactors and devices heated by resistance to the passage of an electrical current.
图 12.2,并增加热流密度。系统如前所述,沿着沸腾曲线移动到点 C,但任何进一步增加热流密度的尝试都会导致系统跳跃到点 E,这可能发生在高于固体熔化温度的温度下,因此导致固体的破坏。因此,点 C 被称为烧毁点,准确知道临界热流密度的值非常重要,因为可能需要系统在接近临界值但不超过临界值的热流密度下运行。涉及控制 q'的应用包括核反应堆和通过电流通过的电阻加热的设备。
Pool Boiling Correlations
池沸腾相关性
Nucleate Pool Boiling
成核池沸腾
Consideration of nucleate boiling involves the prediction of the number of nucleation sites and the rate at which bubbles nucleate from each site. The first relationship de-
考虑到成核沸腾,需要预测成核点的数量以及气泡从每个点成核的速率。第一个关系式 de-
rived showed the influence of nucleation sites on the heat flux, q"s
rived 显示了成核位点对热通量 q" s 的影响
qs C T a nb
(W/m2) as
(W/m2) 作为
(12.7)
where n is the number of active nucleation sites per unit area, and the exponents are approximately a = 1.2 and b = 1/3. Although the type of fluid-surface combination has a considerable influence on the values of C and n, it has been found that, for most commercial surfaces, n is proportional to T5 orT 6. Thus, from Eq. (12.7), it follows
that q" is approximately proportional to T3. Consideration of Eq. (12.7) led to the
q" 大约与 T 3 成正比。考虑到方程 (12.7) 导致了
s e
first and most useful correlation
最初和最有用的相关性
Pool Boiling Correlations 607
池沸腾相关性 607
qs η Hevap [ g (ρ l ρv )/σ ]1 /2 [ Cp,l Te / Cs HevapPrn ] 3
(12.8)
where the subscripts l and v, respectively, denote the saturated liquid and vapor states. The inclusion of the surface tension, σ, follows from the large effect that the surface tension has on the formation and development of bubbles. The coefficient CS and the exponent n depend on combination of surface and liquids and representative values are listed in Table 12.1.
其中下标和 v 分别表示饱和液体和蒸气状态。表面张力σ的包含是由于表面张力对气泡的形成和发展有很大影响。系数 C S 和指数 n 依赖于表面和液体的组合,代表性值列在表 12.1 中。
TABLE 12.1 Values of Cs,f for various combinations of fluids and solids.
表 12.1 各种流体和固体组合的 Cs,f 值。
Surface–fluid combination Cs, f n
表面–流体组合 Cs, f n
Water–copper
水–铜
Scored 0.0068 1.0
得分 0.0068 1.0
Polished Water–stainless steel | 0.0130 0.0130 | 1.0 1.0 |
Chemically etched | 0.0130 | 1.0 |
Mechanically polished | 0.0060 | 1.0 |
Ground and polished Water–brass Water–nickel | 0.0060 0.0060 0.0060 | 1.0 1.0 1.0 |
Water–platinum | 0.0130 | 1.0 |
The Critical Heat Flux for Nucleate Pool Boiling
核态池沸腾的临界热流量
The point C on the boiling curve is an important point and, as has been stated, while it is desirable to operate as close to this point as possible, it is imperative that the actual heat flux does not exceed the critical value. An expression for the critical heat flux has been derived as
沸腾曲线上的点 C 是一个重要的点,正如所述,虽然希望尽可能接近这个点进行操作,但实际的热通量不得超过临界值。临界热通量的表达式已被推导为
q s, max π Hevap ρv [ σg ( ρ1 ρv)/ ρ2]1/4 [(ρv ρ1 )/ ρ1 ]1/ 2
(12.9)
24 v
which, as a first approximation, is independent of surface material and is only weakly dependent on geometry. Replacing the constant (π/24) = 0.131 by an experimental value of 0.149 and approximating the last term in parentheses to unity gives
作为第一近似,它与表面材料无关,仅对几何形状有弱依赖性。将常数 (π/24) = 0.131 替换为实验值 0.149,并将括号中的最后一项近似为 1,得到
qs, max
0.149 Hevapρv[ σg (ρl ρv ) /ρ 2 ]1/ 4
(12.10)
The critical heat flux depends strongly on pressure, mainly through the dependencies of surface tension and the heat of vaporization on pressure.
Minimum Heat Flux
最小热流量
The transition boiling regime is of little practical interest, as it may be obtained only by controlling the surface heater temperature. This regime can be characterized by
过渡沸腾状态在实际应用中兴趣不大,因为它只能通过控制表面加热器温度来获得。该状态可以通过
608 Condensation and Boiling
608 凝结与沸腾
periodic, unstable contact between the liquid and the heated surface. However, the upper limit of this regime is of interest because it corresponds to the formation of a stable blanket or film of vapor and to a minimum heat flux condition. If the heat flux falls below this minimum, the film collapses, causing the surface to cool and nucleate boiling to be reestablished.
液体与加热表面之间的周期性、不稳定接触。然而,这一状态的上限是值得关注的,因为它对应于稳定的蒸汽层或薄膜的形成以及最低热流条件。如果热流低于这个最低值,薄膜会崩溃,导致表面冷却并重新建立成核沸腾。
The use of stability theory allowed derivation of the following equation for the minimum heat flux, qe,D =qmin, from a large horizontal plate.
稳定性理论的使用允许从一个大型水平板推导出以下最小热流量方程,q e D =q min 。
gσ ( ρ ρ ) 1/ 4
q min Cρv Hevap l v
(12.11)
( ρl ρv ) 2
( ρ ρv ) 2
The constant, C, has been experimentally determined to have the value 0.09, which is accurate to approximately 50% for most fluids at moderate pressures, but is less accurate at higher pressures.
常数 C 的实验确定值为 0.09,对于大多数中等压力的流体,其准确度约为 50%,但在较高压力下准确度较低。
Film Pool Boiling
电影池沸腾
At excess temperatures greater than that of the Leidenfrost point, a continuous film of vapor covers the surface which prevents contact between the liquid and the surface. One result, obtained from condensation theory, which applies to film boiling on a cylinder or sphere of diameter D, is of the form
在超过莱登弗罗斯特点的过热温度下,一层连续的蒸汽膜覆盖在表面上,防止液体与表面接触。根据适用于直径为 D 的圆柱或球体的膜沸腾的凝结理论,得到的一个结果是以下形式
h D g (ρ1 ρv) Hev apD 3
NuD
conv
转换
kv
C[ ]1/ 4
vv kv ( Ts Tsat)
(12.12)
The correlation constant C is 0.62 for horizontal cylinders and 0.67 for spheres. The corrected latent heat H΄vap accounts for the sensible energy required to maintain temperatures within the vapor blanket above the saturation temperature. Although it may be approximated as
相关常数 C 对于水平圆柱体为 0.62,对于球体为 0.67。修正后的潜热H΄vap 考虑了维持蒸汽包中温度在饱和温度以上所需的显热。尽管它可以近似为
H H 0.8 c ( T T )
evap evap p,v s sat
蒸发 蒸发 pv s sat
it has a weak dependence on the Prandtl number of the vapor. The properties of the vapor are evaluated at the film temperature
它对蒸汽的普朗特数依赖较弱。蒸汽的性质在膜温度下进行评估。
Tf (Ts Tsat)/2
T f = (T s + T sat ) / 2
and the density of the liquid is evaluated at the saturation temperature.
液体的密度在饱和温度下进行评估。
At elevated surface temperatures (Ts less than or equal to 300°C), radiation heat transfer across the vapor film becomes significant. Since radiation increases the film thickness, it cannot be assumed that the radiative and convective processes are simply additive. Investigation of film boiling from the outer surface of horizontal tubes led to the suggestion that the total heat transfer coefficient be given by an equation of the form
在较高的表面温度(Ts 小于或等于 300°C)下,蒸汽膜中的辐射热传递变得显著。由于辐射增加了膜厚度,因此不能简单地假设辐射和对流过程是相加的。对水平管外表面膜沸腾的研究提出了总热传递系数应由以下形式的方程给出。
h 4/ 3
h 4/ 3
h h 1/ 3
(12.13)
conv rad
If — —
如果 — —
Pool Boiling Correlations 609
池沸腾相关性 609
hrad is less than hconv, a simpler form may be used:
h rad 小于 h conv ,可以使用更简单的形式:
h
The effective radiation coefficient —
有效辐射系数 —
hconv 3 hrad
hconv + 3 hrad
4
is expressed as
表示为
(12.14)
hrad
h εσ (Ts4 T 4 )
(12.15)
rad
Ts Tsat
where ε is the emissivity of the solid and σ is the Stefan-Boltzmann constant.
其中 ε 是固体的发射率,σ 是斯特藩-玻尔兹曼常数。
Note that the analogy between film boiling and film condensation does not hold for small surfaces with high curvature because of the large difference between vapor and liquid film thicknesses for the two processes.
请注意,薄膜沸腾和薄膜冷凝之间的类比在高曲率的小表面上并不成立,因为这两种过程的蒸汽和液体薄膜厚度之间存在很大的差异。
EXAMPLE 12.1
示例 12.1
The bottom of a copper pan, 0.4 m in diameter, is maintained at 120 °C by an electric heater. Estimate the power required to boil water in this pan. What is the rate of evaporation? Estimate the critical heat flux.
一个直径为 0.4 米的铜锅底部通过电加热器保持在 120°C。估算在这个锅中将水煮沸所需的功率。蒸发速率是多少?估算临界热流密度。
Assumptions 1. Steady state
假设 1. 稳态
1 atm.
Tsat = 100°C
Polished surface
抛光表面
Negligible losses from the heater to the surroundings
来自加热器对周围环境的可忽略损失
From Appendix G
来自附录 G
ρ l = 958 kg/m3
cpl = 4220 J/kg K
ηl = 282 106 kg/m s
η = 282 106 kg/m s
Prl = 1.75
Other data
其他数据
From Eq. (12.8)
从公式 (12.8)
Hevap = 2260 kJ/kg
= 58.9 10–3 N/m
ρv = 0.596 kg/m3
Te = Ts – Tsat = 20°C. Therefore, From Fig 12.1, nucleate boiling.
T e = T s – T sat = 20°C。因此,从图 12.1 来看,发生了成核沸腾。
qs η Hevap [ g (ρ l ρv )/σ ]1 /2 [ Cp,l Te / Cs HevapPrn ] 3
610 Condensation and Boiling
610 凝结与沸腾
kg 1/2
千克 1/2
282 ×106 kg × 2260 ×103 J × 9.81
m × (958 0.596) m3 ×
ms kg
4420 J × 20
4420 J × 20
s2 58.9 ×10 3 kg
ms
3
3
kgK
= 1042 kW
0.013 × 2260 ×103 J ×1.70 m2
0.013 × 2260 ×10 3 J ×1.70 m2
kg
千克
Thus, the boiling heat transfer rate is
q q
s A qs π D
1042 kW
m2
Under steady-state conditions,
在稳态条件下,
q m˙evap Hevap
q = m˙evap Δ Hevap
3.142
3.142
0.42
4
m2 131kW
m 2 131 千瓦
m˙
q
1.31 105 W
0.058 kg
0.058 千克
209 kg
209 千克
evap
蒸发
Hevap
2260 103 J s hr
2260 10 3 焦耳·秒·小时
EXAMPLE 12.2
A metal-clad heating element 6-mm in diameter and with an emissivity ε = 1 is immersed horizontally in a water bath. The surface temperature of the metal is 255°C under steady-state boiling conditions. Estimate the power dissipation per unit length of the heater.
一个直径为 6 毫米、发射率ε = 1 的金属包覆加热元件水平浸入水浴中。在稳态沸腾条件下,金属的表面温度为 255°C。估算加热器每单位长度的功率耗散。
From Appendix F
来自附录 F
ρl = 958 kg/m3
Hevap = 2260 kJ/kg ρv = 0.441 kg/m3 cp,v = 1977 J/kg.K
kv = 0.0019 W/m K
ηv = 1.212 105 kg/m s
Te = 2325 – 100 = 125°C
From Fig 12.1, Film Pool Boiling, Convection and radiation
从图 12.1,电影池沸腾,∴ 对流和辐射
qs qsπD hπ DTe
h 4/3
h 4/3
h h
conv rad
k3 ρ
(ρ ρ
)g (H
0.8c
0.8c
T 1/4
Summary 611
摘要 611
hconv
0.62
0.62
v v l v evap p,v e
W 3
kg
m
ηDTe
kg
J J
1/ 4
0.00193 mK
0.62
0.62
0.441
m3 9.81 s
2 958 0.441
m 3 (2260 kg 0.8 1977 kgK
125
1.212 105 kg 6 103 m 125
400( W )
400( W )
m2 K
εσ (T 4 T4 )
hrad
s sat
Ts Tsat
5.67 10 8
19.12 W
19.12 W
m2 K
W
m2 K
4.984 3734
498 373
Then, from Eq. (12.13)
然后,从公式 (12.13)
h 4/3
h 4/3
h h1/3
h 4/3
4004/3
19.12
h 1/3
Trial and error gives
试错法给
Then
然后
h 400 W
h 400 瓦
m2 K
qs
400( W ) 3.184 6 103 (m) 125
m2 K
955 W
m
612 Condensation and Boiling
Summary
摘要
The term boiling is used to describe the process of evaporation at the free surface of a liquid and the modes of boiling are shown graphically on a log-log plot of the variation of the heat flux, from the solid surface of the liquid, with the excess temperature. Newton’s Law gives the relationship between the heat flux and the excess temperature.
“沸腾”一词用于描述液体自由表面上的蒸发过程,沸腾的模式在热流与过剩温度变化的对数-对数图上以图形方式显示。牛顿定律给出了热流与过剩温度之间的关系。
The boiling curve shows the various regimes of boiling. With increasing excess temperature these are (i) free convection boiling, (ii) nucleate boiling, (iii) transition boiling, and (iv) film boiling. Equations have been developed to give the dependence of the surface heat flux on the values of the various properties that influence this flux. The point C on the boiling curve is the critical heat flux, and an expression has been derived for the dependence of this critical heat flux on the same properties.
沸腾曲线显示了沸腾的各种状态。随着过剩温度的增加,这些状态为 (i) 自由对流沸腾,(ii) 核化沸腾,(iii) 过渡沸腾,以及 (iv) 薄膜沸腾。已经开发出方程来给出表面热流密度对影响该热流密度的各种属性值的依赖关系。沸腾曲线上的点 C 是临界热流密度,并且已经推导出该临界热流密度对相同属性的依赖关系的表达式。
The minimum heat flux occurs at the Leidenfrost point, and an equation has been developed to give the dependence of the value of this minimum heat flux on the various properties of the system. At elevated temperatures, radiation heat transfer across the vapor film becomes significant.
最小热流发生在莱顿弗罗斯特点,并且已经开发出一个方程来给出该最小热流值对系统各种属性的依赖关系。在高温下,蒸汽膜中的辐射热传递变得显著。
Problems
问题
PROBLEM 12.1
问题 12.1
Conduct a unit analysis of Eq. (12.9).
对方程 (12.9) 进行单位分析。
PROBLEM 12.2
问题 12.2
The surface of a horizontal, 20-mm diameter cylinder is maintained at an excess temperature of 10°C in saturated water at 1 atm. Calculate the heat flux. Use the data in Appendix G and the data below:
一个直径为 20 毫米的水平圆柱体表面在 1 个大气压的饱和水中保持 10°C 的过剩温度。计算热流。使用附录 G 中的数据和以下数据:
Hevap = 2260 kJ/kg
σ = 58.9 103 kg/m s
ρv = 0.596 kg/m3
PROBLEM 12.3
问题 12.3
A long 2-mm diameter wire passes an electric current and reaches a surface temperature of 120°C when submerged in boiling water at 1 atm pressure. Calculate the boiling heat transfer coefficient.
一根直径为 2 毫米的长电线在 1 个大气压下浸没在沸水中时,电流通过并达到 120°C 的表面温度。计算沸腾换热系数。
PROBLEM 12.4
问题 12.4
Calculate the nucleate pool boiling heat transfer coefficient for water boiling at atmospheric pressure on the outer surface of a platinum-plated 10-mm diameter tube maintained 10°C above the saturation temperature.
计算在大气压下,水在一个外表面为铂涂层、直径为 10 毫米的管子上沸腾时的成核池沸腾换热系数,该管子保持在比饱和温度高 10°C。
PROBLEM 12.5
问题 12.5
Summary 613
摘要 613
The bottom of a copper pan, 150 mm in diameter, is maintained at 115°C by the heating element of an electric range. Calculate
the power required to boil the water in this pan.
将这个锅中的水煮沸所需的功率。
the rate of evaporation.
蒸发速率。
the ratio of the surface heat flux to the critical heat flux.
表面热流密度与临界热流密度的比率。
615
616 Elementary and Derived SI Units and Symbols
617
618
Conversion from British and U.S. Units to SI Units 619
620
623
627
635
639
642 Recommended Readings
Answers to Problems 643
644 Answers to Problems
Answers to Problems 645
646 Answers to Problems
Answers to Problems 647
648 Answers to Problems
648 个问题的答案
Chapter Twelve
第十二章
12.1 LHS = RHS = kg/s3
12.1 LHS= RHS = kg/s³
π
σg ( ρ ρ ) 1/ 4
( ρ ρ )1/ 2
qs,max 24 Hevap
qsmax = 24 Hevap
ρσ
e v e v
2 ρe
W J kg
J m m31/ 4
2 kg
2 千克
3 2
2 kg 1
m m m s
J N.m kg
J N.m 千克
N.m m m31/4
s.m 2
kg m3
千克每立方米
m2
s2 kg
N.m
m m kg
m m m m31/ 4
kg s2
千克 s2
kg
千克
m3 kg 2
m3 kg 2
2 2 kg
s.m
m m
kg
公斤
s m s
s m s
m4 1/ 4
kg s 2
公斤 s 2
s.m 2
s2 m
s 4
kg | kg | |
s 3 | s3 | |
12.2 37.6 W/m | ||
D = 20 mm ρe = 958 kg/m3 | ∆Te = 10° | cs = 0.013 n = 1 |
Cρe = 4220 J/kg · K ∆Hevap = 2260 × 103 J/kg
η = 0.282 × 10–3 kg/m.s σ = 58.9 × 10–3 kg/m.s
Pr = 1.75 ρv = 0.596 kg/m3
g ρ ρ 1/2
C ρ T 3
qs ηHevap
qs'' = ηΔHevap
e s
e e n
σ
σ
Cs Hevap Pr
[0.282 10 3 2260 103] 9.81 (958 0.596) 1/ 2
4420 10 3
58.9 10 3
0.013 2260 103
0.013 × 2260 × 10 3
1.75
637.3 339.3 0.5529
11950 W
11950 W
m2
A π 0.022
4
3.143 10 4
3.143 × 10 4
q 119500 3.143 104
37.6 W
Answers to Problems 649
问题 649 的答案
47.8 kW/m2K
D = 2 mm ∆Te = 20
ρl = 958 kg/m3 Cs = 0.013 n = 1
Cρl = 4220 J/kg·K ∆Hevap = 2260 × 103 J/kg
η = 0.282 × 10–3 kg/m.s σ = 58.9 × 10–3 kg/m.s
Pr = 1.75 ρv = 0.596 kg/m3
g(ρ ρ 1/2 Cρ Te 3
qs ηHevap eσ v
CsHevap Pr
[0.28 103 2260 103] 9.81 (958 0.596) 1/2
4420 20 3
58.9 10 3 0.013 2260 103 1.75
58.9 10 3 0.013 2260 10 3 1.75
637.3 339.3 4.423
956411
h 956411
47820 W
hTe
hΔT e
20 m2 K
47.8 kW
47.8 kW
m2 K
11.9 kW/m2K
ρl = 958 kg/m3 ∆Hevap = 2260 kJ/kg
Cρl = 4220 J/kg·K ρv = 0.596 kg/m3
ηl = 282 × 10–6 kg/m.s σ = 58.9 × 10–3 J/m2
Pr = 1.75 Cs = 0.013 n = 1
g ρ ρ 1/ 2
C ρ T 3
qs ηHevap
e v
e e n
σ Cs Hevap
σ Cs H evap
Pr
339.3 0.5529
= 119313 =h10
h 11931 W 11.9 kW
m2 K m2 K
(i) 7.142 kW (ii) 11.4 kg/h (iii) 0.2
(i) 7.142 千瓦 (ii) 11.4 千克/小时 (iii) 0.2
Cu pan D = 0.15 m ∆Te = 15
ρl = 958 kg/m3 Cs = 0.013 n = 1
Cρl = 4220 J/kg·K ∆ Hevap = 2260 × 103 J/kg
η = 0.282 × 10–3 kg/m.s σ = 58.9 × 10–3 kg/m.s
Pr = 1.75 ρv = 0.596 kg/m3
650 Answers to Problems
650 个问题的答案
gρ ρ 1/2
Cρ T 3
qs ηHevap
l v
l l
σ
σ
CsHevapPr n
CsHevapPr n
[0.28 10 3 2260 103 ] 9.81 (958 0.596) 1/ 2
4420 15 3
58.9 10 3 0.013 2260 103 1.75
637.3 339.3 1.861
W
m2
403.5 Kw
403.5 千瓦
m2
q q A
A π D2 3.142 0.152
0.0177m 2
0.0177 米 2
s s
403.5 0.0177
403.5 0.0177
4 4
7.142 kW
7.142 千瓦
qs
m˙b Hevap
m˙ b
7.142
3.16 10 3 kg
3.16 × 10 3 kg
11.4 kg
11.4 千克
2260 s h
surface heat flux 403469
表面热通量 = 403469
0.2
critical heat flux 2 10 6
Page numbers followed by f and t indicate figures and tables, respectively.
页码后跟 f 和 t 分别表示图形和表格。
A
Absolute mass flux, 523 Absolute molar flux, 530 Absolute pressure, 13 Absolute roughness, 148t Absorption of heat, 405 Absorptivity, 436–437, 436f
绝对质量流量,523 绝对摩尔流量,530 绝对压力,13 绝对粗糙度,148t 热量吸收,405 吸收率,436–437,436f
Acceleration, 8
加速度,8
Activation energy, 95, 515, 516, 518
活化能,95,515,516,518
Adiabatic barrier, 262
绝热障碍,262
Adiabatic flow, 224
绝热流动,224
Ampere, 5
安培,5
Anemometer, 332
风速计,332
Annulus, 69
环形, 69
Approximate integral method, 117, 300–
近似积分法,117,300–
306, 301f, 348–358, 349f, 354f,
355f, 357f, 573–583, 574f, 577f
for boundary layer thickness, 117–124, 118f, 121f, 122f, 123f
边界层厚度,117–124,118f,121f,122f,123f
entry length at pipe entrance, 125, 125f
管道入口处的入口长度,125,125f
Archimedes’ principle, 21, 22f Atmosphere, international standard, 10 Atmospheric air, 8
阿基米德原理,21,22f 大气,国际标准,10 大气空气,8
Atmospheric pressure, 9, 11f, 12 Atomic diffusion, 476–479, 477f, 479f Average heat transfer coefficient, 299,
大气压力,9,11f,12 原子扩散,476–479,477f,479f 平均热传递系数,299,
314, 325
Avogadro’s number, 81, 267, 505
阿伏伽德罗常数,81,267,505
B
Babylonian unit of mass, 1 Barometer, 12f, 13
巴比伦质量单位,1 气压计,12f,13
Barometric formula, 9, 9f, 193, 348
气压公式,9,9f,193,348
Bell curve, 374
钟形曲线,374
Bends/fittings, influence of, 190–191, 190t
弯头/配件的影响,190–191,190t
Bernoulli’s equation, 185–188, 186f, 220
伯努利方程,185–188,186f,220
for compressible fluid flow, 219–220 example, 221
对于可压缩流体流动,219–220 示例,221
Binary diffusion couple, 511
二元扩散偶,511
651
652 Index
Binary mixture
二元混合物
diffusion equation in, 524–527, 525f of ideal gases, 527
理想气体中的扩散方程,524–527,525f,527
Biot number, 368, 369, 371, 385, 389
Biot 数,368,369,371,385,389
Blackbody, 427
黑体,427
Blackbody radiation, 427–430, 428f, 429t
黑体辐射,427–430,428f,429t
functions, 429t
函数,429t
Blake-Kozeny equation, 169, 170 Blasius friction equation, 144 Blasius one-seventh power law, 137,
布莱克-科泽尼方程,169,170 布拉修斯摩擦方程,144 布拉修斯七分之一幂定律,137,
138f, 145
Boltzmann-Matano analysis, 510–514, 512f, 513f, 514f
玻尔兹曼-马塔诺分析,510–514,512f,513f,514f
Boltzmann’s constant, 78, 267, 427
玻尔兹曼常数,78,267,427
Boundary conditions, 39, 120, 298,
边界条件,39,120,298,
302, 486, 556
Boundary layer, 156
边界层,156
concentration, 569
浓度,569
momentum, 115
动量,115
thermal, 295
热量,295
Boundary separation, 165 British system of units, 2 Buoyancy, 21–22, 126, 160, 347
边界分离,165 英制单位,2 浮力,21–22,126,160,347
examples, 22–26, 23f, 24f, 24t Burke-Plummer equation, 170
例子,22–26,23f,24f,24t Burke-Plummer 方程,170
C
Candela, 5
坎德拉,5
Capillary flowmeter, 65–66, 65f example of, 66–68
毛细管流量计,65–66,65f 示例,66–68
Carbon diffusion, 483 Carburization of iron, 486 Cartesian coordinates, 102, 103f,
碳扩散,483 铁的渗碳,486 笛卡尔坐标,102,103f,
127f
Casting
铸造
of aluminum, 406, 407, 411
铝,406,407,411
into cooled metal molds, 408–411, 408f, 410f, 412f
倒入冷却的金属模具中,408–411,408f,410f,412f
of copper, 406, 407, 411
铜,406,407,411
Catalytic surface reactions, 539–542, 540f, 541f
催化表面反应,539–542,540f,541f
Cavitation, 194
气穴现象,194
Celsius, Anders, 4
摄氏度,安德斯,4
Celsius (centigrade) scale, 4 Chapman-Enskog equation, 85, 270,
摄氏(华氏)温标,查普曼-恩斯科格方程,85,270,
562, 576
Chemical diffusion coefficients, 498, 504
化学扩散系数,498,504
Chemical potential, 505 Chemical reaction
化学势,505 化学反应
and mass transfer, 589–593, 591f, 592f
和传质,589–593,591f,592f
in stagnant film, 542–547, 543f, 546f
在静态薄膜中,542–547,543f,546f
Chvorinov’s rule, 404
Chvorinov 的法则,404
Circuit diagram, 460f, 461f, 464f Coefficient of thermal expansion, 4 Collision diameter, 84
电路图,460f,461f,464f 热膨胀系数,4 碰撞直径,84
Collision integral, 85 Compressible fluid flow, 219 Concentration boundary layer, 569
碰撞积分,85 可压缩流体流动,219 浓度边界层,569
Concentration gradient, 479, 503, 504,
浓度梯度,479,503,504,
523
Conduction, 235, 238–240, 239f, 240f in heat sources, 256–267, 257f resistance, 368
导热,235,238–240,239f,240f 在热源中,256–267,257f 电阻,368
for transport of heat. See Heat transport by conduction
用于热量传输。参见通过导热进行的热量传输
Conservation of energy, 186, 348 Conservation of momentum, 104–108,
能量守恒,186,348 动量守恒,104–108,
105f
Constant-pressure heat capacity, 277, 298, 302, 318, 366
定压热容,277,298,302,318,366
Continuous cooling curves, 398f Convection, 235, 236f, 237, 238f
连续冷却曲线,398f 对流,235,236f,237,238f
for heat transfer, 466–471, 468f, 469f, 471f
对于热传递,466–471,468f,469f,471f
heat transfer by, 285–289, 287f. See
热传递,285–289,287f。见
Heat transport by convection resistance, 368
对流阻力的热传输,368
Convective momentum transport, 37, 37f, 38, 49
对流动量输送,37,37f,38,49
Couette flow, 36, 37f, 341, 342, 345f, 346f
库埃特流,36,37f,341,342,345f,346f
Counterdiffusion, equimolar, 528–529
反扩散,等摩尔,528–529
Creeping flow, 125–130, 126f, 127f, 128f, 129f, 130f, 160
爬行流,125–130,126f,127f,128f,129f,130f,160
examples, 130–132
示例,130–132
Critical radius of insulation, 255 Cubit, 1
绝缘的临界半径,255 立方,1
D
D’ Arcy’s law, 167 Darken’s analysis, 502–506
D’ Arcy 定律,167 Darken 的分析,502–506
Decarburization, 491, 493f
脱碳,491,493f
Diffuse emitter, 425
扩散发射器,425
Diffuse-gray surface, 438, 453–458, 453f, 454f, 456f
扩散灰色表面,438,453–458,453f,454f,456f
Diffusion, 520. See also Mass transport by diffusion
扩散,520。另见通过扩散的质量传输
atomic, 476–479, 477f, 479f
原子, 476–479, 477f, 479f
into falling film of liquid, 553–560, 553f
进入液体薄膜,553–560,553f
flux, 479
and kinetic theory of gases, 560–565, 561f, 563t, 564t
气体的动理论,560–565,561f,563t,564t
evaporation, maximum rate of, 565–568, 567t, 568t
蒸发,最大速率,565–568,567t,568t
in semi-infinite system, one-dimensional, 491–497, 492f, 493f, 496f, 497f
在半无限系统中,一维,491–497,492f,493f,496f,497f
in solid state. See Mass transport by diffusion
在固态中。见通过扩散的质量传输
in stagnant film, 542–547, 543f, 546f steady-state, one-dimensional, 529–
在静态薄膜中,542–547,543f,546f 稳态,一维,529–
536, 531, 532f
in substitutional solid solutions, 502, 502f
在替代固体溶液中,502,502f
Diffusion coefficient, 480
扩散系数,480
of carbon, 483, 484f, 493, 494
碳,483,484f,493,494
chemical, 504
化学, 504
interdiffusion, 504
相互扩散,504
self, 506
自我,506
temperature on, 514–518, 515f, 516f, 519f
温度开启,514–518,515f,516f,519f
Diffusion couple, 489
扩散偶,489
infinite, 489–491, 490f, 491f Diffusion distance, 487
无限,489–491,490f,491f 扩散距离,487
Index 653
索引 653
Diffusion equations with convection, 524–527, 525f
对流的扩散方程,524–527,525f
Digit, 1
数字,1
Dimensionless number, 177
无量纲数,177
Directional distribution, 422
方向分布,422
Directional emissivity, 431
方向发射率,431
Discharge coefficient, 209, 225 Dissolution of pure metal in liquid,
排放系数,209,225 纯金属在液体中的溶解,
593–596, 593f, 594f, 597f Drag force, 121, 129, 153, 156, 166
593–596, 593f, 594f, 597f 拖曳力, 121, 129, 153, 156, 166
Drainage
排水
from vessel, 207–209, 208f of vessel using drainage tube,
从船只,207–209,使用排水管的船只 208f,
213–215, 214f
Drainage tube
排水管
in drainage of vessel, 213–215, 214f
在血管排水中,213–215,214f
in emptying vessel, 215–217, 216t, 217f
在排空容器中,215–217,216t,217f
E
Edgar, King, 2
埃德加,国王,2
Egyptian unit of length, 1
埃及长度单位,1
Einstein-Smoluchowski equation, 488,
爱因斯坦-斯莫卢霍夫斯基方程,488,
508
Electrical resistance, 265, 266
电阻,265,266
Electric analogy, 242–243, 248, 458–460, 458f, 459f, 460f
电类比,242–243,248,458–460,458f,459f,460f
Electric current, 5
电流,5
flow, 242
流,242
Electromagnetic waves, 421, 422f Electrostatic dust precipitator, 45–48,
电磁波,421,422f 静电除尘器,45–48,
48f
Elevation head, 205
高程头,205
Emissive power, 425 Emissivity, 431–435, 433f, 434f Emptying of vessel
发射功率,425 发射率,431–435,433f,434f 容器的排空
by discharge through orifice, 209–212, 211f
通过孔口排放,209–212,211f
example, 212–213
示例,212–213
by drainage through drainage tube, 215–217, 216t, 217f
通过排水管排水,215–217,216t,217f
example, 217–219
示例,217–219
654 Index
Ending moment, 166 Energy, concept of, 3
结束时刻,166 能量,概念,3
Energy balance, 276, 280f, 322–331,
能量平衡,276,280f,322–331,
323f, 324f, 336, 337, 385, 398,
402, 453
Energy parameters of metals, 93t Engineering units, origins of, 1–5
金属的能量参数,93t 工程单位,起源,1–5
British system of units, 2 concept of energy, 3 force measurement, 3
英制单位系统,2 能量概念,3 力的测量,3
International System of Units, 5 metric system, 2–3
国际单位制,5 公制,2–3
pressure measurement, 3
压力测量,3
temperature scales, 4–5 unit of power, 4
温度尺度,4–5 功率单位,4
Enthalpy, 297, 302, 366, 382
焓,297,302,366,382
flux, 550, 552
Entry length, 125, 125f
条目长度,125,125f
Equation of conservation of momentum, 107
动量守恒方程,107
Equation of continuity, 102–104, 103f, 111t
连续性方程,102–104,103f,111t
Equation of motion
运动方程
cylindrical coordinates, 112–113
圆柱坐标,112–113
in rectangular coordinates, 111t–112t in spherical coordinates, 114t
在矩形坐标中,111t–112t 在球坐标中,114t
Equimolar counterdiffusion, 528–529
等摩尔反向扩散,528–529
Equivalent diameter, 151
等效直径,151
Equivalent length, 190
等效长度,190
Ergun’s equation, 170–175, 175f Error function, 374–376, 374f, 375f,
Ergun 方程,170–175,175f 误差函数,374–376,374f,375f,
376t, 403, 486, 487f
Euken’s equation, 272
Euken 方程,272
Evaporation, maximum rate of, 565–568, 567t, 568t
蒸发,最大速率,565–568,567t,568t
Evaporative cooling, 586–588, 587f wet bulb psychrometer, 588–589
蒸发冷却,586–588,587f 湿球心理测量仪,588–589
F
Farhenheit, Daniel, 4
法伦海特,丹尼尔,4
Fick’s first law of diffusion, 480–483, 481f, 539
菲克第一扩散定律,480–483,481f,539
Fick’s second law of diffusion, 483–489, 484f, 485, 485f, 487f, 488f
菲克第二扩散定律,483–489,484f,485,485f,487f,488f
Film boiling, 608
Film model, 538–539, 538f Film pool boiling, 605 Finger, 2
电影模型,538–539,538f 电影池沸腾,605 手指,2
Finite difference technique, 278, 279f, 382, 383f, 384, 388, 389
有限差分法,278,279f,382,383f,384,388,389
Fittings, 190–191, 190t
配件,190–191,190t
Flow coefficient, 226
流量系数,226
Flow energy, 203
流能,203
Flowmeter, capillary, 65
流量计,毛细管,65
Flow velocity, 198
流速,198
measurement, 226
测量,226
Flow work, 186
流动工作,186
Fluid flow, 30, 181
流体流动,30,181
in annulus, 69–74
在环形区域,69–74
example of, 74–76
示例,74–76
in cylindrical pipes, 317–322, 317f, 319f
在圆柱形管道中,317–322,317f,319f
down an inclined plane, 48–51, 49f, 50f
沿斜面向下,48–51,49f,50f
equations, 166
方程,166
between flat parallel plates, 40–45, 41f, 43f, 44f
在平行的平面之间,40–45,41f,43f,44f
examples, 45–48, 48f
示例,45–48,48f
in noncircular ducts, 151–153 in open channel, 205–206, 206f
在非圆形管道中,151–153 在开放通道中,205–206,206f
example, 207
示例,207
over horizontal flat plate, 115–117, 116f
在水平平板上,115–117,116f
in pipes, 228
在管道中,228
problems, 133–134
问题,133–134
in vertical cylinder tube, 53–57, 53f, 54f, 56f
在垂直圆柱管中,53–57,53f,54f,56f
example of, 57–Fluid flow equations, 64
示例,57–流体流动方程,64
Fluidized bed, 144, 175–179 Flux, types of, 423
流化床,144,175–179 通量,类型,423
Force, 33
力,33
balances, 130f
余额,130f
Forced convection, 295–, 331, 334
强制对流,295–,331,334
Form drag, 129
表面阻力,129
Fourier number, 369, 373
傅里叶数,369,373
H
Haaland’s correlation, 148
哈兰德的相关性,148
Index 655
索引 655
Fourier’s
Free convection boiling, 604
自由对流沸腾,604
Free convection, mass transfer by, 583–586, 584f, 585f
自由对流,质量传递,583–586,584f,585f
Friction
摩擦
drag force, 129
拖曳力,129
turbulence-induced, 1, 139 Friction factor, 141–151, 144f, 148t,
湍流引起的,1,139 摩擦因子,141–151,144f,148t,
149f, 153, 165, 170
definition of, 141, 153, 165
定义为,141,153,165
local, 156
本地, 156
Friction loss, 188–189, 204 Friction loss factor, 190
摩擦损失,188–189,204 摩擦损失系数,190
Fully-developed hydrodynamic flow, 125
完全发育的水动力流,125
Fully-developed temperature profile, 319
完全发展的温度分布,319
G
Galileo, 3
伽利略, 3
Galileo number, 177
伽利略数,177
Gallon, 2
加仑,2
Gas law, ideal, 59
理想气体定律,59
Gauge pressure, 13, 16, 21
表压,13,16,21
Gay-Lussac, Joseph, 4
盖-吕萨克,约瑟夫,4
General energy equation, 335–341 dissipation factor, 341–346 General heat conduction equation,
一般能量方程,335–341 耗散因子,341–346 一般热传导方程,
274–277, 275f, 276f
Goldschmidt’s atomic diameter, 91, 93t
Goldschmidt 的原子直径,91,93t
Gram, 3
克,3
Grashof number, 351, 352, 353, 357,
Grashof 数,351,352,353,357,
586
mass transfer, 586
质量传递,586
Gravitation, 3
引力,3
Gravitational field, 8
引力场,8
Gravitational force, 205, 336
引力,205,336
Gravity-induced fluid flow, 197, 206f
重力引起的流体流动,197,206f
Hagen-Poiseuille equation, 57, 139, 143
哈根-波伊塞方程,57,139,143
Hand, 1
手,1
Head, concept of, 203–205
头部,概念,203–205
Heat and mass transfer, simultaneous, 586–589
热量和质量传递,同时进行,586–589
Heat balance, 302, 368 Heat conduction
热平衡,302,368 热传导
general equation, 274–277, 275f, 276f
一般方程,274–277,275f,276f
at steady state, 278–285, 279f, 280f, 281f, 283f, 284f
在稳态下,278–285,279f,280f,281f,283f,284f
Heat diffusivity, 403
热扩散率,403
Heat flow, 242, 263
热流,242,263
hollow cylinder, 244–245 hollow sphere, 246, 247f
空心圆柱,244–245 空心球,246,247f
in semi-infinite systems, 376–379 through composite cylindrical wall,
在半无限系统中,通过复合圆柱壁,376–379
252–254, 253f
through composite wall, 248–249, 248f
通过复合墙,248–249,248f
through plane slab, 243
通过平板,243
Heat flux, 254, 256f, 300, 308, 326, 552
热流, 254, 256f, 300, 308, 326, 552
Heat generation
热量产生
in plane slab, 257–263, 260f rate, 265, 266
在平面板中,257–263,260f 速率,265,266
within solid, 398–401, 399f, 401f in solid cylinder, 263–265, 264f
在固体中,398–401,399f,401f 在固体圆柱中,263–265,264f
Heat loss, 245 Heat transfer
热损失,245 热传递
by convection, 285–289, 287f
通过对流,285–289,287f
by convection/radiation, 466–471, 468f, 469f, 471f
通过对流/辐射,466–471,468f,469f,471f
Heat transfer coefficient, 237, 248,
热传递系数,237,248,
296, 306, 309f, 319, 335, 352,
372, 552, 570
Heat transport by conduction conduction, 238–240, 239f, 240f conduction in heat sources, 256–267,
导热,238–240,239f,240f 热源中的导热,256–267,
257f
electric analogy, 242–243
电气类比,242–243
656 Index
example, 240–242, 241f, 242f, 244,
例子,240–242,241f,242f,244,
245, 249–252, 251f, 254, 259,
273, 281, 286–289
features of, 235, 236f
特征,235,236f
Fourier’s law, 236–238, 237f, 238f heat conduction
傅里叶定律,236–238,237f,238f 热传导
general equation, 274–277, 275f, 276f
一般方程,274–277,275f,276f
at steady state, 278–285, 279f, 280f, 281f, 283f, 284f
在稳态下,278–285,279f,280f,281f,283f,284f
heat flow
热流
hollow cylinder, 244–245 hollow sphere, 246, 247f through composite cylindrical
空心圆柱,244–245 空心球,246,247f 通过复合圆柱
wall, 252–254, 253f
墙, 252–254, 253f
through composite wall, 248–249, 248f
通过复合墙,248–249,248f
through plane slab, 243 heat generation
通过平板,243 热生成
in plane slab, 257–263, 260f
在平面板中,257–263,260f
in solid cylinder, 263–265, 264f heat transfer by convection, 285–
在固体圆柱体中,263–265,264f 通过对流的热传递,285–
289, 287f
Newton’s law, 236–238, 237f, 238f problems, 290–294
牛顿定律,236–238,237f,238f 问题,290–294
resistance heating of electric wires, 265–267, 265f
电线的电阻加热,265–267,265f
thermal conductivity
热导率
of gas mixtures, 273–274, 274f and kinetic theory of gases,
气体混合物,273–274,274f 和气体的动理论,
267–273, 269f, 271f, 272t
Heat transport by convection from cylinders, 358–360, 359t
圆柱体的对流热传输,358–360,359t
energy balance, 322–331, 323f, 324f examples, 307–311, 309f, 312–315,
能量平衡,322–331,323f,324f 示例,307–311,309f,312–315,
313f, 316–317, 326–331, 328f,
331–333, 331t, 344–346, 345f,
346f, 353–358, 354f, 355f, 357f
during fluid flow in cylindrical pipes, 317–322, 317f, 319f
在圆柱形管道中的流体流动,317–322,317f,319f
general energy equation, 335–341 dissipation factor, 341–346
一般能量方程,335–341 耗散因子,341–346
from horizontal cylinders, 331–333
来自水平圆柱,331–333
from horizontal flat plate approximate integral method,
从水平平板近似积分法,
300–306, 301f
turbulent boundary flow, 311–315
湍流边界流,311–315
at uniform constant temperature, 295–315, 296f, 297f, 299t,
在均匀恒定温度下,295–315,296f,297f,299t,
301f
with uniform heat flux, 315–317 problems, 361–364
均匀热流,315–317 问题,361–364
from sphere, 334–335
来自球体,334–335
from vertical plate, 346–348, 347f approximate integral method,
来自垂直板,346–348,347f 近似积分法,
348–358, 349f, 354f, 355f,
357f
Heat transport by thermal radiation. See Thermal radiation in heat transport Hemisperical emissivity, 431, 432, 438
热辐射的热传输。参见热传输中的热辐射 半球发射率,431,432,438
Hemispherical emissive power, 425 Henry’s law, 506
半球辐射功率,425 亨利定律,506
Hohlraum, 437–439, 438f
Hydraulic radius, 168
水力半径,168
Hydrodynamic flow, 323
水动力流动,323
Hydrogen diffusion, 480, 481f, 498
氢扩散,480,481f,498
Hydrometer, 24
比重计,24
I
Ideal fluid, 115 Ideal gas law, 527
理想流体,115 理想气体定律,527
Incompressible fluid flow, 186f Incompressible fluid pressure, 15–17,
不可压缩流体流动,186f 不可压缩流体压力,15–17,
16f
Inertial force, 135–136
惯性力,135–136
Infinite diffusion couple, 489–491, 490f, 491f
无限扩散偶,489–491,490f,491f
Intensity
强度
of emission, 423–425, 423f of turbulence, 137
排放,423–425,423f 湍流,137
Interdiffusion coefficient, 504, 505, 561,
相互扩散系数,504,505,561,
562, 564
measurement, 510–514, 512f, 513f, 514f
测量,510–514,512f,513f,514f
Intermediate law, 162
中级法,162
Internal energy, 336, 338 International standard atmosphere, 10 International System of Units, 5
内能,336,338 国际标准大气,10 国际单位制,5
Laplace’s equation, 277
拉普拉斯方程,277
Large span, 1
大跨度,1
Latent heat, 586
潜热,586
Index 657
索引 657
Inviscid
Iron-carbon phase diagram, 491, 492f Irradiation, 426
铁碳相图,491,492f 辐照,426
Isobaric system, 505
等压系统,505
Isobaric thermal expansivity, 340, 348,
等压热膨胀系数,340,348,
583
Isotherm(s), 274, 275f
等温线,274,275f
Isothermal cavity, 437, 437f, 438, 438f
等温腔,437,437f,438,438f
Isothermal compressibility, 340
等温压缩性,340
J
Joule, James, 4
焦耳,詹姆斯,4
K Ka, 2
Kelvin, Lord, 5
凯尔文,勋爵,5
Kilogram, 5
千克,5
Kinematic viscosity, 58, 277, 315
运动粘度,58,277,315
Kinetic energy, 141, 163, 186, 187,
动能,141,163,186,187,
188, 203, 336
Kinetic theory of gases, 78, 97, 267, 560–565, 561f, 563t, 564t
气体的动理论,78,97,267,560–565,561f,563t,564t
and thermal conductivity, 267–273, 269f, 271f, 272t
和热导率,267–273,269f,271f,272t
viscosity calculation from, 78–90, 79f, 80f, 83f, 84f, 85f, 86f, 86t,
粘度计算来自,78–90,79f,80f,83f,84f,85f,86f,86t,
87t, 89f
Kiogram, 3
Kirchhoff’s law and Hohlraum, 437–439, 437f, 438f
基尔霍夫定律和霍尔朗,437–439,437f,438f
Kirkendall effect, 502, 502f Kus, 1
Kirkendall 效应,502,502f Kus,1
L
Laminar flow, 30, 31, 31f, 51, 97, 135,
层流,30,31,31f,51,97,135,
137, 138, 139, 139f, 143, 152,
169, 187, 296, 313f, 322, 323
to turbulent flow, transition from, 154f
到湍流,过渡自,154f
Langmuir equation, 566
朗缪尔方程,566
of solidification, 402, 404
固化,402,404
Leidenfrost point, 605, 608
莱登弗罗斯特点,605,608
Lennard-Jones function, 562 Lennard-Jones potential, 84, 86t, 92f Lewis number, 573, 577f
Lennard-Jones 函数,562 Lennard-Jones 势,84,86t,92f Lewis 数,573,577f
Libra, 2
天秤座, 2
Light intensity, 5
光强度,5
Local flow velocity, 136, 136f, 138f Log mean temperature difference, 325 Loss of head, 204
局部流速,136,136f,138f 对数平均温差,325 失头,204
Lumped capacitance method (Newtonian cooling), 365–373, 367f, 368f
集中电容法(牛顿冷却),365–373,367f,368f
Lumped thermal capacitance, 365
集中热容,365
M
Manometer, 13, 13f, 14, 14f, 65, 65f, 66 Mass and molar fluxes, 522–524
压力计,13,13f,14,14f,65,65f,66 质量和摩尔通量,522–524
Mass flow rate, 44, 45, 51, 57, 186,
质量流量,44,45,51,57,186,
220, 322
Mass flux, 522 Mass transfer
质量通量,522 质量传递
by free convection, 583–586, 584f, 585f
通过自由对流,583–586,584f,585f
at large fluxes/concentrations, 547–550, 549f, 550f
在大流量/浓度下,547–550,549f,550f
Mass transfer coefficient, 570, 579,
质量传递系数,570,579,
580, 581
and concentration boundary layer, 569–573, 571f
和浓度边界层,569–573,571f
Mass transport by diffusion
通过扩散的质量传输
atomic diffusion, 476–479, 477f, 479f
原子扩散,476–479,477f,479f
Boltzmann-Matano analysis, 510–514, 512f, 513f, 514f
玻尔兹曼-马塔诺分析,510–514,512f,513f,514f
Darken’s analysis, 502–506 diffusion in substitutional solid
Darken 的分析,502–506 替代固体中的扩散
solutions, 502, 502f
解决方案,502,502f
examples, 480–483, 481f, 486–489, 487f, 488f, 495–497, 496f,
示例,480–483,481f,486–489,487f,488f,495–497,496f,
497f, 499–501, 501f, 509–510
658 Index
Fick’s first law of diffusion, 480–483, 481f
菲克第一扩散定律,480–483,481f
Fick’s second law of diffusion, 483–489, 484f, 485f, 487f, 488f
菲克第二扩散定律,483–489,484f,485f,487f,488f
infinite diffusion couple, 489–491, 490f, 491f
无限扩散耦合,489–491,490f,491f
phase change, 491–497, 492f, 493f, 496f, 497f
相变,491–497,492f,493f,496f,497f
problems, 520–521
问题,520–521
self-diffusion coefficient, 506–510, 507f
自扩散系数,506–510,507f
steady-state diffusion, 498–501, 498f
稳态扩散,498-501,498f
temperature on diffusion coefficient, 514–518, 515f, 516f, 519f
温度对扩散系数的影响,514-518,515f,516f,519f
Mass transport in fluids approximate integral method,
流体中的质量输运近似积分法、
573–583, 574f, 577f
573-583、574f、577f
catalytic surface reactions, 539–542, 540f, 541f
催化表面反应,539-542,540f,541f
diffusion and kinetic theory of gases, 560–565, 561f, 563t, 564t
气体扩散和动力学理论,560-565,561f,563t,564t
evaporation, maximum rate of, 565–568, 567t, 568t
蒸发,最大速率,565-568,567t,568t
diffusion into falling film of liquid, 553–560, 553f
扩散到下降的液膜中,553-560,553f
equations of diffusion with convection, 524–527, 525f
对流扩散方程,524-527,525f
equimolar counterdiffusion, 528–529
等摩尔反扩散,528-529
evaporative cooling, 586–588, 587f wet bulb psychrometer, 588–589
蒸发冷却, 586-588, 587f 湿球温度计, 588-589
examples, 532–536, 535f, 537,
例子,532-536,535f,537、
538f, 546–547, 559–560,
538f, 546-547, 559-560,
564–565, 566, 569, 578–580,
564-565, 566, 569, 578-580,
581, 582–583, 587–588, 589,
581, 582-583, 587-588, 589,
592–593, 592f
592-593, 592f
film model, 538–539, 538f
电影模式,538-539,538f
on heat transfer, 550–553, 551f
热传递,550-553,551f
at large fluxes, 547–550, 549f, 550f mass and molar fluxes, 522–524 mass transfer by free convection,
大通量时,547-550,549f,550f 质量和摩尔通量,522-524 自由对流的质量传递、
583–586, 584f, 585f
583-586、584f、585f
mass transfer coefficient, 569–573, 571f
传质系数,569-573,571f
mixed control, 589–593, 591f, 592f, 593–596, 593f, 594f, 597f
混合控制,589-593,591f,592f,593-596,593f,594f,597f
one-dimensional steady-state diffusion, 529–536, 531, 532f
一维稳态扩散,529-536,531,532f
one-dimensional transport, 527
一维运输,527
problems, 598–600
问题,598-600
in stagnant film, 542–547, 543f, 546f
在静态薄膜中,542–547,543f,546f
sublimation of sphere into stationary gas, 536–537, 538f
球体升华为静态气体,536–537,538f
Mass transport Stanton number, 577 Matano interface, 511
质量传输斯坦顿数,577 Matano 界面,511
Matrix inversion method, 393 Maxwell’s equation, 339 Mean free path, 80
矩阵求逆法,393 麦克斯韦方程,339 平均自由程,80
Mean residence time, 76–78, 77f, 78f Mean square distance, 477
平均滞留时间,76–78,77f,78f 平均平方距离,477
Mean temperature, 319
平均温度,319
Mechanical energy, 338, 344 Mechanical energy balance
机械能,338,344 机械能平衡
bends/fittings, influence of, 190–191, 190t
弯头/配件,影响,190–191,190t
Bernoulli’s equation, 185–188, 186f for compressible fluid flow,
伯努利方程,185–188,186f 用于可压缩流体流动,
219–220
drainage from vessel, 207–209, 208f drainage tube, use of, 213–215, 214f emptying of vessel
从容器排水,207–209,208f 排水管的使用,213–215,214f 容器的排空
by discharge, 209–212, 211f
通过排放,209–212,211f
by drainage, 215–217, 216t, 217f examples, 191–203, 197f, 207,
通过排水,215–217,216t,217f 示例,191–203,197f,207,
212–213, 217–219, 221,
223–224
fluid flow in open channel, 205–206, 206f
开放渠道中的流体流动,205–206,206f
friction loss, 188–189 head, concept of, 203–205
摩擦损失,188–189 头部,概念,203–205
orifice plate, 225–228, 226f, 227f, 228f
孔板,225–228,226f,227f,228f
pitot tube, 221–223, 222f
皮托管,221–223,222f
problems, 229–234, 230f, 232f, 233f
问题,229–234,230f,232f,233f
Mercury, 12
水星,12
Mesh Biot number, 385, 386, 388, 389,
网格生物数,385,386,388,389,
397, 400
Mesh Fourier number, 385, 387, 388,
网格傅里叶数,385,387,388,
389, 392f
Metal castings, solidification of
金属铸件,凝固过程
into cooled metal molds, 408–411, 408f, 410f, 412f
倒入冷却的金属模具中,408–411,408f,410f,412f
sand casting, 401–408, 402f, 405f Meter, 5
砂铸造,401–408,402f,405f 米,5
Mina, 1
米娜,1
Minimum heat flux, 607
最小热流量,607
Mixed control, 589–593, 591f, 592f, 593–596, 593f, 594f, 597f
混合控制,589–593,591f,592f,593–596,593f,594f,597f
Mobility, 505
移动性,505
Modes of boiling, 603
沸腾的模式,603
Modified Bernoulli equation, 188 Molar flux, 522
修正的伯努利方程,188 摩尔通量,522
Molar heat capacity, 224, 272
摩尔热容,224,272
Momentum, 6
动量,6
convective, 37
对流,37
viscous, 37
粘稠,37
Momentum balance, 36, 41, 49, 55,
动量平衡,36,41,49,55,
70, 72, 118
Momentum boundary layer, 115, 116f, 118f
动量边界层,115,116f,118f
Momentum conservation, 36–40, 37f, 38f
动量守恒,36–40,37f,38f
Momentum flux, 81
动量通量,81
Momentum transport, 34
动量传输,34
Monatomic gas, 78, 267
单原子气体,78,267
Monochromatic emissivity, 431
单色发射率,431
Monochromatic intensity, 424 Monochromatic radiation emission, 422f Monton, Gabriel, 2
单色强度,424 单色辐射发射,422f Monton, Gabriel, 2
Moody diagram, 148, 149f
穆迪图,148,149f
N
Natural convection, 349f, 361 Navier-Stokes equation, 108–113,
自然对流,349f,361 纳维-斯托克斯方程,108–113,
111t–112t
application to simple flow system, 113–115, 114t
简单流动系统的应用,113–115,114t
Index 659
索引 659
Nernst-Einstein equation, 506 Newton, Sir Isaac, 3
能斯特-爱因斯坦方程,506 牛顿,艾萨克·牛顿爵士,3
Newtonian cooling (lumped capacitance method), 365–373, 367f, 368f
牛顿冷却(集中电容法),365–373,367f,368f
Newtonian fluids, 33
牛顿流体,33
Newton’s law, 160, 163, 236–238,
牛顿定律,160,163,236–238,
237f, 238f, 296
of cooling, 237
冷却,237
of viscosity, 32–35, 480
粘度,32–35,480
examples, 35–36, 36f
示例,35–36,36f
Node, 278
节点,278
Non-Newtonian cooling. See Transient heat flow
非牛顿冷却。参见瞬态热流
Non-Newtonian fluids, 33
非牛顿流体,33
Non-steady-state diffusion in solid, one-dimensional, 483–489, 484f, 485f, 487f, 488f
固体中的非稳态扩散,一维,483–489,484f,485f,487f,488f
Nucleate boiling, 605 Nucleate pool boiling, 606
成核沸腾,605 成核池沸腾,606
Nusseldt number, 299, 300, 313, 315,
努塞尔数,299,300,313,315,
316, 331, 352, 355f, 357, 357f,
316, 331, 352, 355f, 357, 357f
368, 570, 571
O
Ohm’s law, 265, 458
欧姆定律,265,458
Opaque medium, 437
不透明介质,437
Orifice plate, 225–228, 226f, 227f, 228f
孔板,225–228,226f,227f,228f
P
Palm, 1
棕榈,1
Permanent gas, 4, 5
永久气体,4,5
Permeability, specific, 167
渗透率,特定,167
Permeability coefficient, 167, 169 Phase change, 491–497, 492f, 493f,
渗透系数,167,169 相变,491–497,492f,493f,
496f, 497f
496o, 497o
Phase diagram, 593, 593f Photons, 421
相图,593,593f 光子,421
Pike’s peak, 10, 11, 11f
派克峰,10,11,11f
Pipe flow, 322
管道流动,322
Pi theorem, 142
Pi 定理,142
Pitot tube, 221–223, 222f example, 223–224
皮托管,221–223,222f 示例,223–224
660 Index
Pitot tube coefficient, 222 Planck’s distribution, 427, 428f Porosity, 167, 168
皮托管系数,222 普朗克分布,427,428f 孔隙率,167,168
Potential energy, 83, 84, 84f, 186, 193 Power, unit of, 4
势能,83,84,84f,186,193 功,单位,4
Prandtl number, 298, 305, 331, 335,
普朗特数,298,305,331,335,
349, 356, 572, 577f
Pressure, 3
压力,3
absolute, 12
绝对,12
gauge, 12
量规,12
gradient, 181, 298
梯度,181,298
head, 205
头, 205
in static fluids
在静态流体中
concept, 5–11, 6f, 9f, 11f examples, 17–21, 18f, 19f, 20f in incompressible fluids, 15–17,
概念,5–11,6f,9f,11f 示例,17–21,18f,19f,20f 在不可压缩流体中,15–17,
16f
measurement of, 11–15, 12f, 13f, 14f
测量,11–15,12f,13f,14f
Pressure drop, 62–64, 63f, 68, 167,
压力降,62–64,63f,68,167,
189, 201, 228
calculation, 182 Psychrometer, wet bulb, 588
计算,182 湿度计,湿球,588
Q
Quanta, 421
R
Radial flux, 266 Radiation
径向通量,266 辐射
constants, 427
常量,427
emission, 422f, 423
排放,422f,423
exchange. See Thermal radiation in heat transport
交换。见热辐射与热传输
for heat transfer, 466–471, 468f, 469f, 471f
对于热传递,466–471,468f,469f,471f
heat transfer coefficient, 467, 468f shields, 460–463, 461f
热传递系数,467,468f 屏蔽,460–463,461f
Radiosity, 426–427, 453
辐射度,426–427,453
Random-walk process, 476–479, 477f, 479f
随机游走过程,476–479,477f,479f
Raoult’s law, 506
拉乌尔定律,506
Rayleigh number, 353, 355f, 358
雷 leigh 数,353,355f,358
Real packed beds, 171 Reciprocity relation, 441, 443
真实填充床,171 互惠关系,441,443
Reduced pressure, 566
降低压力,566
Reduced temperature, 91, 566
降低温度,91,566
Reduced viscosity, 91
降低的粘度,91
Reduced volume, 91, 566
减少的体积,91, 566
Reflectivity, 436–437, 436f Relative roughness, 148, 149f Reradiating surface, 463–466, 464f Resistance heating of electric wires,
反射率,436–437,436f 相对粗糙度,148,149f 重新辐射表面,463–466,464f 电线的电阻加热,
265–267, 265f
Reynolds analogy, 311
雷诺兹类比,311
Reynold’s number, 31, 51, 64, 67, 126,
雷诺数,31,51,64,67,126,
136, 138f, 139f, 140, 149f, 157f,
199, 326, 331, 332, 351, 357, 372,
588
defined, 169
定义,169
Rigorous theory of rigid-sphere molecules, 81
刚性球分子的严格理论,81
Roman unit of mass, 2 Roughness
罗马质量单位,2 粗糙度
absolute, 148, 148t
绝对,148,148t
relative, 148
相对,148
S
Sand casting, 401–408, 402f, 405f Schmidt number, 572, 576, 577f, 580
砂铸造,401–408,402f,405f 施密特数,572,576,577f,580
Second, 5
第二,5
Self-diffusion coefficient, 506–510, 507f Shape factor, 172, 444f, 445f
自扩散系数,506–510,507f 形状因子,172,444f,445f
Shear force, 141
剪切力,141
Shear stress, 33, 34, 36, 40, 43f, 44, 50,
剪切应力,33,34,36,40,43f,44,50,
50f, 72, 81, 108, 119, 121, 126f,
129, 142, 154, 159, 296, 345
Shekel, 1
谢克尔,1
Sherwood number, 570, 571, 573, 580,
舍伍德数,570,571,573,580,
581
SI (International system of units), 5 Sievert’s law, 481, 498
国际单位制(SI),5 西弗定律,481,498
Size particles, 173
粒子大小,173
Slag, 51
渣, 51
Small cubit, 1
小立方体,1
Small span, 1
小跨度,1
Solidification of metal castings. See
金属铸件的固化。见
Transient heat flow Specific area means, 171 Specific permeability, 167
瞬态热流 特定面积,171 特定渗透率,167
Spectral distribution, 422 Spectral emissive power, 425 Spectral intensity, 424
光谱分布,422 光谱发射功率,425 光谱强度,424
Spectral irradiation, 426
光谱辐照度,426
Spectral radiosity, 426
光谱辐射度,426
Spherical particles and Ergun’s equation, 170–175, 175f
球形颗粒与 Ergun 方程,170–175,175f
Spontaneous escape process, 594, 595, 596 Stagnant film
自发逃逸过程,594,595,596 静止薄膜
diffusion/chemical reaction in, 542–547, 543f, 546f
扩散/化学反应,542–547,543f,546f
heat transfer in, 550–553, 551f Stagnation point, 163
热传递,550–553,551f 停滞点,163
Stanton number, 310, 311, 577
斯坦顿数,310,311,577
mass transport, 577 Steady-state diffusion
质量传输,577 稳态扩散
one-dimensional, 529–536, 531, 532f through composite wall, 498–501, 498f
一维,529–536,531,532f 通过复合墙,498–501,498f
Steady-state heat conduction, 278 Stefan-Boltzmann law, 428, 451, 456 Stefan’s apparatus, 531, 532f Stoichiometry coefficients, 545
稳态热传导,278 斯特凡-玻尔兹曼定律,428,451,456 斯特凡装置,531,532f 计量系数,545
Stoke’s law, 130, 160, 162 Stress
斯托克斯定律,130,160,162 应力
normal, 108
正常, 108
shear, 33
剪切,33
Stress tensor, 107
应力张量,107
Sublimation of sphere into stationary gas, 536–537, 538f
球体升华为静止气体,536–537,538f
Substantial derivative, 109, 110
实质导数,109,110
Summation rule, 441, 442, 443 Surface radiation resistance, 454 Surface roughness, 189
求和规则,441,442,443 表面辐射电阻,454 表面粗糙度,189
T
Temperature
温度
on diffusion coefficient, 514–518, 515f, 516f, 519f
扩散系数,514–518,515f,516f,519f
distribution, 247f, 345f, 346f
分布,247f,345f,346f
Index 661
索引 661
gradient, 347f, 366, 368f, 408, 412–
梯度,347f,366,368f,408,412–
416, 412f, 415f, 553
scales, 4–5
鳞片,4–5
Thermal boundary layer, 295, 309f Thermal conductivity, 236, 237, 239f,
热边界层,295,309f 热导率,236,237,239f,
240f, 256, 298, 368, 369
of gas mixtures, 273–274, 274f
气体混合物,273–274,274f
and kinetic theory of gases, 267–273, 269f, 271f, 272t
气体的动理论,267–273,269f,271f,272t
of sand, 401
沙子,401
Thermal diffusivity, 277, 298, 318
热扩散率,277,298,318
Thermal energy, 4, 36, 269, 336, 366,
热能,4,36,269,336,366,
382, 480
Thermal expansion, 4
热膨胀,4
Thermal radiation in heat transport absorptivity/reflectivity/transmissiv-
热辐射在热传输中的吸收率/反射率/透射率
ity, 436–437, 436f
城市,436–437,436f
blackbody radiation, 427–430, 428f, 429t
黑体辐射,427–430,428f,429t
electric analogy, 458–460, 458f, 459f, 460f
电类比,458–460,458f,459f,460f
electromagnetic waves, 421, 422f emissive power, 425
电磁波,421,422f 发射功率,425
emissivity, 431–435, 433f, 434f examples, 430, 435, 443–450, 444f,
发射率,431–435,433f,434f 示例,430,435,443–450,444f,
445f, 445t, 446f, 446t, 447f,
448f, 450t, 451–452, 452f, 456–
458, 456f, 461–463, 465–466,
467–471, 468f, 469f, 471f
features of, 421
特征,421
heat transfer by convection/radiation, 466–471, 468f, 469f, 471f
对流/辐射的热传递,466–471,468f,469f,471f
intensity, 423–425, 423f
强度,423–425,423f
irradiation, 426
辐照,426
Kirchhoff’s law and Hohlraum, 437–439, 437f, 438f
基尔霍夫定律和霍尔朗,437–439,437f,438f
problems, 472–475
问题,472–475
radiation emission, 422f, 423 radiation exchange
辐射发射,422f,423 辐射交换
between blackbodies, 450–452, 450f, 452f
在黑体之间,450–452,450f,452f
between diffuse-gray surfaces, 453–458, 453f, 454f, 456f
在扩散灰色表面之间,453–458,453f,454f,456f
662 Index
between surfaces, 439–443, 440f, 441f, 442f, 443–450, 444f,
表面之间,439–443,440f,441f,442f,443–450,444f,
445f, 445t, 446f, 446t, 447f,
448f, 450t
radiation shields, 460–463, 461f radiosity, 426–427
辐射屏蔽,460–463,461f 辐射度,426–427
reradiating surface, 463–466, 464f Thermal resistance, 365
再辐射表面,463–466,464f 热阻,365
to heat flow, 251 Thermodynamic temperature, 5
热流,251 热力学温度,5
Thompson, Benjamin, 4
汤普森,本杰明,4
Torricelli, 11
托里切利,11
Torricelli vacuum, 12 Transient heat flow
托里切利真空,12 瞬态热流
examples, 369–373, 379–382, 380f, 382f, 386–394, 387t, 388t,
示例,369–373,379–382,380f,382f,386–394,387t,388t,
389f, 390f, 391f, 392f, 394t,
396–398, 396f, 398f, 399–401,
399f, 401f, 405–408, 411, 412f,
414–416, 415f
lumped capacitance method (Newtonian cooling), 365–373, 367f, 368f
集中电容法(牛顿冷却),365–373,367f,368f
non-Newtonian cooling, 373–379 error function, 374–376, 374f,
非牛顿冷却,373–379 误差函数,374–376,374f,
375f, 376t
heat generation within solid, 398–401, 399f, 401f
固体内的热生成,398–401,399f,401f
in one-dimensional finite systems, 382–394, 383f, 387t, 388t, 389f, 390f, 391f, 392f,
在一维有限系统中,382–394,383f,387t,388t,389f,390f,391f,392f,
394t
in semi-infinite systems, 376–379 in two-dimensional finite sys-
在半无限系统中,376–379 在二维有限系统中
tems, 394–401, 396f, 398f, 399f, 401f
problems, 416–420 solidification of metal castings
问题,416–420 金属铸件的凝固
into cooled metal molds, 408–411, 408f, 410f, 412f
倒入冷却的金属模具中,408–411,408f,410f,412f
sand casting, 401–408, 402f, 405f
砂铸造,401–408,402f,405f
temperature gradients, 412–416, 412f, 415f
温度梯度,412–416,412f,415f
Transition boiling, 605
过渡沸腾,605
Transmissivity, 436–437, 436f
透过率,436–437,436f
T’ser, 1
Tube bundle theory, 167–170, 167f Turbine, efficiency of, 196 Turbulence
管束理论,167–170,167f 涡轮,效率,196 湍流
definition of, 136
定义为,136
intensity of, 137
强度,137
Turbulent boundary flow, 311–315 Turbulent flow, 30, 31, 31f, 135
湍流边界流,311–315 湍流,30,31,31f,135
concept of, 135–138, 136f, 138f, 139f
概念,135–138,136f,138f,139f
in cylindrical pipes
在圆柱形管道中
fluid flow in noncircular ducts, 151–153
非圆形管道中的流体流动,151–153
and friction factor, 141–151, 144f, 148t, 149f
和摩擦因子,141–151,144f,148t,149f
examples, 145–147, 148, 150–151,
示例,145–147,148,150–151,
157–160, 160–163, 166,
173–175, 177–179
fluid flow equations, 166 graphical representation of,
流体流动方程,166 的图形表示,
139–141, 140f
inertial force, 135–136
惯性力,135–136
over flat plate, 153–160, 157f, 159f past submerged cylinder, 163–165,
在平板上,153–160,157f,159f 经过沉没圆柱,163–165,
164f, 165f
past submerged sphere, 160–163, 161f
过去的沉没球体,160–163,161f
problems (1–16), 181–184
问题 (1–16),181–184
Reynolds number, 61, 136, 138f,
雷诺数,61,136,138f,
140, 149f, 157f
through packed beds D’Arcy’s law, 167
通过填充床的达西定律,167
fluidized beds, 175–179 spherical particles and Ergun’s
流化床,175–179 球形颗粒和 Ergun 的
equation, 170–175, 175f tube bundle theory, 167–170,
方程,170–175,175f 管束理论,167–170,
167f
turbulence, definition of, 136
湍流,定义,136
of helium, 82, 83f
氦的,82,83f
Index 663
索引 663
viscous
U
Uniform heat flux, 315–317 Unit of power, 4
均匀热流,315–317 功率单位,4
V
Velocity
速度
average, 44
平均,44
gradient, 33, 34, 347f
渐变,33,34,347f
head, 205
头, 205
local mass average, 524 local molar average, 524
局部质量平均,524 局部摩尔平均,524
Vena contracta, 225
View factor, 439, 446f, 450t View resistance, 455
视角因子,439,446f,450t 视角电阻,455
Viscosity, 33, 135
粘度,33,135
calculation from kinetic theory of gases, 78–85, 79f, 80f, 83f, 84f, 85f
气体动理论的计算,78–85,79f,80f,83f,84f,85f
example of, 85–90, 86f, 86t, 87t, 89f
示例,85–90,86f,86t,87t,89f
of liquid metals, 90–94, 91f, 92f, 93t, 94f
液态金属,90–94,91f,92f,93t,94f
example of, 94–96, 94f, 96t of Ne, 82, 83f
Ne 的例子,94–96,94f,96t,82,83f
Viscous force, 135–136
粘性力,135–136
Viscous momentum transport, 37, 37f, 38, 48, 69
粘性动量传输,37,37f,38,48,69
Void fraction, 167–168
空隙率,167–168
Volume flow rate, 44, 45
体积流量,44,45
Von Kármán integral, 119, 155
冯·卡门积分,119,155
W
Water, flow of, 141 Watt, James, 4
水,流动,141 瓦特,詹姆斯,4
Wet bulb psychrometer, 588–589 Wien’s displacement law, 427 Wilke’s formula, 87, 273
湿球心理测量仪,588–589 Wien 位移定律,427 Wilke 公式,87,273
Winchester standard, 2 Wind chill factor, 295
温彻斯特标准,2 风寒指数,295
X
X-ray scattering curves, 91, 92f
X 射线散射曲线,91,92f
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AN INTRODUCTION
Transport Phenomena in Materials Engineering
材料工程中的传输现象
SECOND EDITION, By David R. Gaskell
第二版,作者:大卫·R·加斯克尔
This classic text on fluid flow, heat transfer, and mass transport has been brought up to date in this second edition. The author has added a chapter on “Boiling and Conden-sation” that expands and rounds out the book’s comprehensive coverage on transport phenomena. These new topics are particularly important to current research in renewable energy resources involving technologies such as windmills and solar panels.
这本关于流体流动、热传递和质量传输的经典文本在第二版中进行了更新。作者增加了一个关于“沸腾和冷凝”的章节,扩展并完善了本书对传输现象的全面覆盖。这些新主题对于当前涉及风力发电机和太阳能电池板等技术的可再生能源资源研究尤为重要。
The book provides you and other materials science and engineering students and professionals with a clear yet thorough introduction to these important concepts. It balances the explanation of the fundamentals governing fluid flow and the transport of heat and mass with common applications of these fundamentals to specific systems existing in materials engineering. You will benefit from:
本书为您和其他材料科学与工程的学生和专业人士提供了对这些重要概念的清晰而全面的介绍。它在解释流体流动和热量及质量传输的基本原理与这些基本原理在材料工程中特定系统的常见应用之间取得了平衡。您将受益于:
The use of familiar examples such as air and water to introduce the influences of
使用熟悉的例子,如空气和水,来介绍影响因素
properties and geometry on fluid flow.
流体流动的性质和几何。
An organization with sections dealing separately with fluid flow, heat transfer, and mass transport. This sequential structure allows the development of heat transport concepts to employ analogies of heat flow with fluid flow and the development of mass transport concepts to employ analogies with heat transport.
一个组织有不同的部门分别处理流体流动、热传递和质量传输。这种顺序结构允许热传输概念的发展利用流体流动的类比,以及质量传输概念的发展利用热传输的类比。
Ample high-quality graphs and figures throughout.
整篇文章中有大量高质量的图表和图形。
Key points presented in chapter summaries.
章节摘要中呈现的要点。
End of chapter exercises and solutions to selected problems.
章节末尾的练习和选定问题的解决方案。
An all new and improved comprehensive index.
全新改进的综合索引。
ABOUT THE AUTHOR
关于作者
David