Introduction to Thermal Systems Engineering PDF

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Introduction to Thermal Systems Engineering: Thermodynamics, Fluid Mechanics, and Heat Transfer Michael J. Moran The Ohio State University Howard N. Shapiro Iowa State University of Science and Technology Bruce R. Munson Iowa State University of Science and Technology David P. DeWitt Purdue Universi...

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Introduction to Thermal Systems Engineering: Thermodynamics, Fluid Mechanics, and Heat Transfer

Michael J. Moran The Ohio State University

Howard N. Shapiro Iowa State University of Science and Technology

Bruce R. Munson Iowa State University of Science and Technology

David P. DeWitt Purdue University

John Wiley & Sons, Inc.

Acquisitions Editor Production Manager Production Editor Senior Marketing Manager Senior Designer Production Management Services Cover Design Cover Photograph

Joseph Hayton Jeanine Furino Sandra Russell Katherine Hepburn Harold Nolan Suzanne Ingrao Howard Grossman © Larry Fleming. All rights reserved.

This book was typeset in 10/12 Times Roman by TechBooks, Inc. and printed and bound by R. R. Donnelley and Sons (Willard). The cover was printed by The Lehigh Press. The paper in this book was manufactured by a mill whose forest management programs include sustained yield harvesting of its timberlands. Sustained yield harvesting principles ensure that the number of trees cut each year does not exceed the amount of new growth. This book is printed on acid-free paper. 

Copyright © 2003 by John Wiley & Sons, Inc. 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, photocopying recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (508) 750-8400 fax (508) 750-4470. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc. 605 Third Avenue, New York, NY 10158-0012, (212) 850-6008, E-mail: [email protected]. To order books or for customer service call 1-800-CALL-WILEY(225-5945). ISBN 0-471-20490-0 Printed in the United States of America. 10

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Preface ur objective is to provide an integrated introductory presentation of thermodynamics, fluid mechanics, and heat transfer. The unifying theme is the application of these principles in thermal systems engineering. Thermal systems involve the storage, transfer, and conversion of energy. Thermal systems engineering is concerned with how energy is utilized to accomplish beneficial functions in industry, transportation, the home, and so on. Introduction to Thermal Systems Engineering: Thermodynamics, Fluid Mechanics, and Heat Transfer is intended for a three- or four-credit hour course in thermodynamics, fluid mechanics, and heat transfer that could be taught in the second or third year of an engineering curriculum to students with appropriate background in elementary physics and calculus. Sufficient material also is included for a two-course sequence in the thermal sciences. The book is suitable for self-study, including reference use in engineering practice and preparation for professional engineering examinations. SI units are featured but other commonly employed engineering units also are used. The book has been developed in recognition of the teamoriented, interdisciplinary nature of engineering practice, and in recognition of trends in the engineering curriculum, including the move to reduce credit hours and the ABETinspired objective of introducing students to the common themes of the thermal sciences. In conceiving this new presentation, we identified those critical subject areas needed to form the basis for the engineering analysis of thermal systems and have provided those subjects within a book of manageable size. Thermodynamics, fluid mechanics, and heat transfer are presented following a traditional approach that is familiar to faculty, and crafted to allow students to master fundamentals before moving on to more challenging topics. This has been achieved with a more integrated presentation than available in any other text. Examples of integration include: unified notation (symbols and definitions); engaging caseoriented introduction to thermodynamics, fluid mechanics, and heat transfer engineering; mechanical energy and thermal energy equations developed from thermodynamic principles; thermal boundary layer concept as an extension of hydrodynamic boundary layer principles; and more.

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Features especially useful for students are:

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Readable, highly accessible, and largely selfinstructive presentation with a strong emphasis on engineering applications. Fundamentals and applications provided at a digestible level for an introductory course.

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An engaging, case-oriented introduction to thermal systems engineering provided in Chapter 1. The chapter describes thermal systems engineering generally and shows the interrelated roles of thermodynamics, fluid mechanics, and heat transfer for analyzing thermal systems.

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Generous collection of detailed examples featuring a structured problem-solving approach that encourages systematic thinking.

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Numerous realistic applications and homework problems. End-of-chapter problems classified by topic.

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Student study tools (summarized in Sec. 1.4) include chapter introductions giving a clear statement of the objective, chapter summary and study guides, and key terms provided in the margins and coordinated with the text presentation.

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A CD-ROM with hyperlinks providing the full print text plus additional content, answers to selected end-of-chapter problems, short fluid flow video clips, and software for solving problems in thermodynamics and in heat transfer.

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Access to a website with additional learning resources: http://www.wiley.com/college/moran

Features especially useful for faculty are:

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Proven content and student-centered pedagogy adapted from leading textbooks in the respective disciplines: M.J. Moran and H.N. Shapiro, Fundamentals of Engineering Thermodynamics, 4th edition, 2000. B.R. Munson, D.F. Young, and T.H. Okiishi, Fundamentals of Fluid Mechanics, 4th edition, 2002. F.P. Incropera and D.P. DeWitt, Fundamentals of Heat and Mass Transfer, 5th edition, 2002.

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Concise presentation and flexible approach readily tailored to individual instructional needs. Topics are carefully structured to allow faculty wide latitude in choosing the coverage they provide to students—with no loss in continuity. The accompanying CD-ROM provides additional content that allows faculty further opportunities to customize their courses and/or develop two-semester courses. iii

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Preface

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Highly integrated presentation. The authors have worked closely as a team to ensure the material is presented seamlessly and works well as a whole. Special attention has been given to smooth transitions between the three core areas. Links between the core areas have been inserted throughout. Instructor’s Manual containing complete, detailed solutions to all the end-of-chapter problems to assist with course planning.

A Note on the Creative Process How did four experienced authors come together to develop this book? It began with a face-to-face meeting in Chicago sponsored by our Publisher. It was there that we developed the broad outline of the book and the unifying thermal systems engineering theme. At first we believed it would be a straightforward task to achieve our objectives by identifying the core topics in the respective subject areas and adapting material from our previous books to provide them concisely. We quickly found that it was easier to agree on overall objectives than to achieve them. Since we come from the somewhat different technical cultures of thermodynamics, fluid mechanics, and heat transfer, it might be expected that challenges would be encountered as the author team reached for a common vision of an integrated book, and this was the case. Considerable effort was required to harmonize different viewpoints and writing styles, as well as to agree on the breadth and depth of topic coverage. Building on the good will generated at our Chicago meeting, collaboration among the authors has been extraordinary as we have taken a problem-solving approach to this project. Authors have been open and mutually supportive, and have shared common goals. Concepts were honed and issues resolved in weekly telephone conferences, countless e-mail exchanges, and frequent one-to-one telephone conversations. A common vision evolved as written material was

exchanged between authors and critically evaluated. By such teamwork, overlapping concepts were clarified, links between the three disciplines strengthened, and a single voice achieved. This process has paralleled the engineering design process we describe in Chapter 1. We are pleased with the outcome. We believe that we have developed a unique, userfriendly text that clearly focuses on the essential aspects of the subject matter. We hope that this new, concise introduction to thermodynamics, fluid mechanics, and heat transfer will appeal to both students and faculty. Your suggestions for improvement are most welcome.

Acknowledgments Many individuals have contributed to making this book better than it might have been without their participation. Thanks are due to the following for their thoughtful comments on specific sections and/or chapters of the book: Fan-Bill Cheung (Pennsylvania State University), Kirk Christensen (University of Missouri-Rolla), Prateen V. DeSai (Georgia Institute of Technology), Mark J. Holowach (Pennsylvania State University), Ron Mathews (University of Texas-Austin), S. A. Sherif (University of Florida). Organization and topical coverage also benefited from survey results of faculty currently teaching thermal sciences courses. Thanks are also due to many individuals in the John Wiley & Sons, Inc., organization who have contributed their talents and efforts to this book. We pay special recognition to Joseph Hayton, our editor, who brought the author team together, encouraged its work, and provided resources in support of the project. April 2002 Michael J. Moran Howard N. Shapiro Bruce R. Munson David P. DeWitt

Contents THERMO Is Thermal Systems 1 What Engineering? 1 1.1 1.2 1.3 1.4

Getting Started 1 Thermal System Case Studies 3 Analysis of Thermal Systems 7 How to Use This Book Effectively Problems 11

4 Evaluating Properties 4.1

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4.2 p-v-T Relation 60 4.3 Retrieving Thermodynamics Properties 4.4 p-v-T Relations for Gases 79

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Evaluating Properties Using the Ideal Gas Model 81

Thermodynamics: Introductory Concepts and Definitions 14

2.1 2.2 2.3 2.4

Defining Systems 14 Describing Systems and Their Behavior 16 Units and Dimensions 19 Two Measurable Properties: Specific Volume and Pressure 21 2.5 Measuring Temperature 23 2.6 Methodology for Solving Problems 26 2.7 Chapter Summary and Study Guide 27 Problems 28

3 Using Energy and the First Law 3.1 3.2 3.3 3.4 3.5 3.6

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Evaluating Properties: General Considerations 60

2 Getting Started in

of Thermodynamics

Fixing the State

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Reviewing Mechanical Concepts of Energy 31 Broadening Our Understanding of Work 33 Modeling Expansion or Compression Work 36 Broadening Our Understanding of Energy 40 Energy Transfer by Heat 41 Energy Accounting: Energy Balance for Closed Systems 43 3.7 Energy Analysis of Cycles 51 3.8 Chapter Summary and Study Guide 54 Problems 55

4.5 Ideal Gas Model 81 4.6 Internal Energy, Enthalpy, and Specific Heats of Ideal Gases 83 4.7 Evaluating u and h of Ideal Gases 85 4.8 Polytropic Process of an Ideal Gas 89 4.9 Chapter Summary and Study Guide 91 Problems 91

5 Control Volume Analysis Using Energy

96

5.1 Conservation of Mass for a Control Volume 5.2 Conservation of Energy for a Control Volume 99 5.3 Analyzing Control Volumes at Steady State 5.4 Chapter Summary and Study Guide 117 Problems 118

6 The Second Law of Thermodynamics

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6.1 Introducing the Second Law 123 6.2 Identifying Irreversibilities 126 6.3 Applying the Second Law to Thermodynamic Cycles 128 6.4 Maximum Performance Measures for Cycles Operating between Two Reservoirs 131 v

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6.5 6.6

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Contents

Carnot Cycle 136 Chapter Summary and Study Guide Problems 137

Using Entropy

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7.10 Introducing Entropy 141 7.20 Retrieving Entropy Data 143 7.30 Entropy Change in Internally Reversible Processes 149 7.40 Entropy Balance for Closed Systems 151 7.50 Entropy Rate Balance for Control Volumes 157 7.60 Isentropic Processes 162 7.70 Isentropic Efficiencies of Turbines, Nozzles, Compressors, and Pumps 166 7.80 Heat Transfer and Work in Internally Reversible, Steady-State Flow Processes 171 7.90 Accounting for Mechanical Energy 174 7.10 Accounting for Internal Energy 176 7.11 Chapter Summary and Study Guide 177 Problems 178

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Vapor Power and Refrigeration Systems 185

Vapor Power Systems

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8.10 Modeling Vapor Power Systems 185 8.20 Analyzing Vapor Power Systems—Rankine Cycle 187 8.30 Improving Performance—Superheat and Reheat 198 8.40 Improving Performance—Regenerative Vapor Power Cycle 202

Vapor Refrigeration and Heat Pump Systems 206 8.50 Vapor Refrigeration Systems 207 8.60 Analyzing Vapor-Compression Refrigeration Systems 209 8.70 Vapor-Compression Heat Pump Systems 217 8.80 Working Fluids for Vapor Power and Refrigeration Systems 218 8.90 Chapter Summary and Study Guide 218 Problems 219

9 Gas Power Systems Internal Combustion Engines

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9.1 Engine Terminology 223 9.2 Air-Standard Otto Cycle 225 9.3 Air-Standard Diesel Cycle 230

Gas Turbine Power Plants

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9.4 9.5 9.6 9.7

Modeling Gas Turbine Power Plants Air-Standard Brayton Cycle 235 Regenerative Gas Turbines 243 Gas Turbines for Aircraft Propulsion (CD-ROM) 247 9.8 Chapter Summary and Study Guide Problems 247

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Applications 10 Psychrometric (CD-ROM) 250 All material in Chapter 10 is available on the CD-ROM only. 10.1 Introducing Psychrometric Principles 10.2 Evaluating the Dew Point Temperature 10.3 Psychrometers: Measuring the Wet-Bulb and Dry-Bulb Temperatures 10.4 Psychrometric Charts 10.5 Analyzing Air-Conditioning Processes 10.6 Cooling Towers 10.7 Chapter Summary and Study Guide Problems

FLUIDS Started in Fluid 11 Getting Mechanics: Fluid Statics 11.1 11.2 11.3 11.4

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Pressure Variation in a Fluid at Rest 251 Measurement of Pressure 255 Manometry 256 Mechanical and Electronic Pressure and Measuring Devices 259 11.5 Hydrostatic Force on a Plane Surface 260 11.6 Buoyancy 264 11.7 Chapter Summary and Study Guide 265 Problems 265

Contents

Momentum and Mechanical 12 The Energy Equations 269 12.1 12.2 12.3 12.40 12.50 12.60 12.70 12.80 12.90 12.10

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Fluid Flow Preliminaries 269 Momentum Equation 272 Applying the Momentum Equation 273 The Bernoulli Equation 278 Further Examples of Use of the Bernoulli Equation 280 The Mechanical Energy Equation 282 Applying the Mechanical Energy Equation 283 Compressible Flow (CD-ROM) 286 One-dimensional Steady Flow in Nozzles and Diffusers (CD-ROM) 286 Flow in Nozzles and Diffusers of Ideal Gases with Constant Specific Heats (CD-ROM) 286 Chapter Summary and Study Guide 287 Problems 287

13 Similitude, Dimensional

Analysis, and Modeling

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13.10 Dimensional Analysis 293 13.20 Dimensions, Dimensional Homogeneity, and Dimensional Analysis 294 13.30 Buckingham Pi Theorem and Pi Terms 297 13.40 Method of Repeating Variables 298 13.50 Common Dimensionless Groups in Fluid Mechanics 301 13.60 Correlation of Experimental Data 302 13.70 Modeling and Similitude 304 13.80 Chapter Summary and Study Guide 308 Problems 309

and External Flow 14 Internal 313 Internal Flow

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14.10 General Characteristics of Pipe Flow 314 14.20 Fully Developed Laminar Flow 315 14.30 Laminar Pipe Flow Characteristics (CD-ROM) 316 14.40 Fully Developed Turbulent Flow 316

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14.50 Pipe Flow Head Loss 317 14.60 Pipe Flow Examples 322 14.70 Pipe Volumetric Flow Rate Measurement (CD-ROM) 325

External Flow 14.80 14.90 14.10 14.11 14.12

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Boundary Layer on a Flat Plate 326 General External Flow Characteristics 330 Drag Coefficient Data 332 Lift 335 Chapter Summary and Study Guide 337 Problems 338

HEAT TRANSFER Started in Heat 15 Getting Transfer: Modes, Rate Equations and Energy Balances

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15.10 Heat Transfer Modes: Physical Origins and Rate Equations 342 15.20 Applying the First Law in Heat Transfer 348 15.30 The Surface Energy Balance 351 15.40 Chapter Summary and Study Guide 355 Problems 356

Transfer by 16 Heat Conduction 359 16.10 16.20 16.30 16.40

Introduction to Conduction Analysis 359 Steady-State Conduction 362 Conduction with Energy Generation 373 Heat Transfer from Extended Surfaces: Fins 377 16.50 Transient Conduction 385 16.60 Chapter Summary and Study Guide 395 Problems 397

Transfer by 17 Heat Convection 405 17.10 The Problem of Convection

Forced Convection 17.20 External Flow 17.30 Internal Flow

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Free Convection 17.40 Free Convection

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Radiative Exchange Between Surfaces in Enclosures 489

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Convection Application: Heat Exchangers 446 17.50 Heat Exchangers 446 17.60 Chapter Summary and Study Guide Problems 458

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Transfer by 18 Heat Radiation 468

A Appendices

18.1 Fundamental Concepts 468 18.2 Radiation Quantities and Processes 18.3 Blackbody Radiation 473

Spectrally Selective Surfaces

18.5 The View Factor 489 18.6 Blackbody Radiation Exchange 492 18.7 Radiation Exchange between Diffuse-Gray Surfaces in an Enclosure 495 18.8 Chapter Summary and Study Guide 502 Problems 503

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Index to Property Tables and Figures 511

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18.4 Radiation Properties of Real Surfaces

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Index

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Things You Should Know About Interactive Thermodynamics (IT) and

Interactive Heat Transfer (IHT)

What is the software all about? IT and IHT provided on your CD-ROM are Windows-based, general-purpose, nonlinear equation solvers with built-in functions for solving thermodynamics and heat transfer problems. The packages were designed for use with the texts Fundamentals of Engineering Thermodynamics (Moran & Shapiro, 4th Ed., 2000, Wiley) and Introduction to Heat Transfer (Incropera & DeWitt, 4th Ed., 2002, Wiley), respectively. The equation numbering, text section/topic identification, and content, are specific to those texts. However, the software is also well suited for use with Introduction to Thermal Systems Engineering (ITSE). It is our purpose here to identify features of IT and IHT that will help you make good use of the software in solving thermodynamics and heat transfer problems.

Why use IT and IHT? You should consider IT and IHT as productivity tools to reduce the tediousness of calculations...