Principles of Enhanced Heat Transfer

This book is essential for anyone involved in the design of high-performance heat exchangers or heat devices, also known as "second generation heat transfer technology." Enhanced surfaces are geometrics with special shapes that promote much higher rates of heat transfer than smooth or plain surfaces. This revision presents the subject matter just beyond the introductory level and traces the advancement of heat transfer research in areas such as integral-fin and micro-fin tubes, complex plate-fin geometries, and micro-channels for single-phase and two-phase applications.

NEW TO THIS EDITION:
BL Design and enhancement of micro-thermal devices responsible for cooling micro-reactors, electronic chips, and micro-combustors.
BL More practice problems, theoretically-based equations, and correlations to predict the heat transfer and friction characteristics of a multitude of enhancement concepts.
BL A comprehensive list of over 9,500 literature sources on the subject of enhancedheat transfer provided on a CD-ROM.
This expansion of the first book published on the subject of enhanced heat transfer is a valuable addition to the working libraries of HVAC professionals and mechanical, aerospace, and chemical engineers. As a textbook, it introduces senior undergraduates and graduate students to state-of-the-art technology and advanced modeling methodology.

CHAPTER 1: INTRODUCTION TO ENHANCED HEAT TRANSFER1.1 INTRODUCTION 1.2 THE ENHANCEMENT TECHNIQUES Passive Techniques Active Techniques 1.2.3 Technique vs. Mode 1.3 PUBLISHED LITERATURE General Remarks U.S. Patent Literature Manufacturer's Information 1.4 BENEFITS OF ENHANCEMENT 1.5 COMMERCIAL APPLICATIONS OF ENHANCED SURFACES Heat (and Mass) Exchanger Types of Interest Illustrations of Enhanced Tubular Surfaces Enhanced Fin Geometries for Gases Plate Type Heat Exchangers Cooling Tower Packings Distillation and Column Packings Factors Affecting Commercial Development 1.6 DEFINITION OF HEAT TRANSFER AREA 1.7 POTENTIAL FOR ENHANCEMENT PEC Example 1.1 PEC Example 1.2 1.8 REFERENCES CHAPTER 2: HEAT TRANSFER FUNDAMENTALS2.l INTRODUCTION 2.2 HEAT EXCHANGER DESIGN THEORY Thermal Analysis Heat Exchanger Design Methods Comparison of LMTD and NTU Design Methods 2.3 FIN EFFICIENCY 2.4 HEAT TRANSFER COEFFICIENTS AND FRICTION FACTORS Laminar Flow Over Flat Plate Laminar Flow in Ducts Turbulent Flow in Ducts Tube Banks (Single-Phase Flow) Film Condensation Nucleate Boiling 2.5 CORRECTION FOR VARIATION OF FLUID PROPERTIES Effect of Changing Fluid Temperature Effect Local Property Variation 2.6 REYNOLDS ANALOGY 2.7 FOULING OF HEAT TRANSFER SURFACES 2.8 CONCLUSIONS 2.9 REFERENCES 2.10 NOMENCLATURE CHAPTER 3: PERFORMANCE EVALUATION CRITERIA FOR SINGLE-PHASE FLOWS3.1 PERFORMANCE EVALUATION CRITERIA (PEC) 3.2 PEC FOR HEAT EXCHANGERS 3.3 PEC FOR SINGLE PHASE FLOW Objective Function and Constraints Algebraic Formulation of the PEC Simple Surface Performance Comparison Constant Flow Rate Fixed Flow Area 3.4 THERMAL RESISTANCE ON BOTH SIDES 3.5 RELATIONS FOR St AND f 3.6 HEAT EXCHANGER EFFECTIVENESS 3.7 EFFECT OF REDUCED EXCHANGER FLOW RATE 3.8 FLOW NORMAL TO FINNED TUBE BANKS 3.9 VARIANTS OF THE PEC 3.10 COMMENTS ON OTHER PERFORMANCE INDICATORS Shah Soland et al. 3.11 CONCLUSIONS 3.12 REFERENCES 3.13 NOMENCLATURE CHAPTER 4: PERFORMANCE EVALUATION CRITERIA FOR TWO-PHASE HEAT EXCHANGERS4.1 INTRODUCTION 4.2 OPERATING CHARACTERISTICS OF TWO-PHASE HEAT EXCHANGERS 4.3 ENHANCEMENT IN TWO-PHASE HEAT EXCHANGE SYSTEMS Work Consuming Systems Work Producing Systems Heat Actuated Systems 4.4 PEC FOR TWO-PHASE HEAT EXCHANGE SYSTEMS 4.5 PEC CALCULATION METHOD PEC Example 4.1 PEC Example 4.2 4.6 CONCLUSIONS 4.7 REFERENCES 4.8 NOMENCLATURE CHAPTER 5: PLATE-AND-FIN EXTENDED SURFACES5.1 INTRODUCTION 5.2 OFFSET-STRIP FIN 5.2.1 Enhancement Principle5.2.2 PEC Example 5.1 5.2.3 Analytically Based Models for j and f vs. Re 5.2.4 Transition from Laminar to Turbulent Region 5.2.5 Correlations for j and f vs. Re 5.2.6 Use of OSF with Liquids 5.2.7 Effect of Percent Fin Offset 5.2.7 Effect of Burred Edges5.3 LOUVER FIN 5.3.1 Heat Transfer and Friction Correlations 5.3.2 Flow Structure in the Louver Fin Array 5.3.3 Analytical Model for Heat Transfer and Friction 5.3.4 PEC Example 5.2 5.4 CONVEX LOUVER FIN 5. 5 WAVY FIN 5.6 3-DIMENSIONAL CORRUGATED FINS 5.7 PERFORATED FIN 5.8 PIN FINS AND WIRE MESH 5.9 VORTEX GENERATORS 5.9.1 Types of Vortex Generators 5.9.2 Vortex Generators on a Plate-Fin Surface 5.10 METAL FOAM FIN 5.11 PLAIN FIN PEC Example 5.3 5.12 ENTRANCE LENGTH EFFECTS 5.13 PACKINGS FOR GAS-GAS REGENERATORS 5. 14 NUMERICAL SIMULATION 5.14.1 Offset-strip fins 5.14.2 Louver Fins 5. 14.3 Wavy Channels 5.14.4 Chevron Plates 5.14.5 Summary 5.15 CONCLUSIONS 5.16 REFERENCES 5.13 NOMENCLATURE CHAPTER 6: EXTENDED SURFACES OUTSIDE TUBES6.1 INTRODUCTION 6.2 THE GEOMETRIC PARAMETERS AND THE REYNOLDS NUMBER Dimensionless Variables Definition of Reynolds Number Definition of the Friction Factor Sources of Data 6.3 PLAIN PLATE-FINS ON ROUND TUBES Effect of Fin SpacingCorrelations for Staggered Tube Geometries Correlations for Inline Tube Geometries 6.4 PLAIN INDIVIDUALLY FINNED TUBES Circular Fins with Staggered Tubes Low Integral-Fin Tubes 6.5 ENHANCED PLATE FIN GEOMETRIES WITH ROUND TUBES Wavy Fin Offset Strip Fins Convex Louver Fins Louvered Fin Perforated Fins Mesh Fins Vortex Generators 6.6 ENHANCED CIRCULAR FIN GEOMETRIES Illustrations of Enhanced Fin Geometries Spine or Segmented Fins Wire Loop Fins 6.7 OVAL AND FLAT TUBE GEOMETRIES Oval vs. Circular Individually Finned TubesFlat Extruded Aluminum Tubes with Internal Membranes Plate-and-Fin Automotive Radiators Vortex Generators on Flat or Oval Fin-Tube Geometry 6.8 ROW EFFECTS - STAGGERED AND INLINE LAYOUTS 6.9 HEAT TRANSFER COEFFICIENT DISTRIBUTION (PLAIN FINS)Experimental Methods Plate Fin and Tube Measurements Circular Fin and Tube Measurements6.10 PERFORMANCE COMPARISON OF DIFFERENT GEOMETRIES Geometries Compared Analysis Method Calculated Results 6. 11 PROGRESS ON NUMERICAL SIMULATION 6.12 RECENT PATENTS ON ADVANCED FIN GEOMETRIES 6.13 HYDROPHILIC COATINGS 6.14 CONCLUSIONS 6.15 REFERENCES 6.16 NOMENCLATURE CHAPTER 7: INSERT DEVICES FOR SINGLE PHASE FLOW7.1 INTRODUCTION 7.2 TWISTED TAPE INSERT Laminar Flow Predictive Methods for Laminar Flow Turbulent Flow PEC Example 7.1 Twisted Tapes in Annuli Twisted Tapes in Rough Tubes 7.3 SEGMENTED TWISTED TAPE INSERT 7.4 DISPLACED ENHANCEMENT DEVICES Turbulent Flow Laminar Flow PEC Example 7.2 7.5 WIRE COIL INSERTS Laminar Flow Turbulent Flow 7.6 EXTENDED SURFACE INSERT 7.7 TANGENTIAL INJECTION DEVICES 7.8 CONCLUSIONS 7.9 REFERENCES 7.10 NOMENCLATURE CHAPTER 8: INTERNALLY FINNED TUBES AND ANNULI8.1 INTRODUCTION 8.2 INTERNALLY FINNED TUBES Laminar Flow Turbulent Flow PEC Example 1 8.3 SPIRALLY FLUTED TUBES The General Atomics Spirally Fluted Tube Spirally Indented Tube 8.4 ADVANCED INTERNAL FIN GEOMETRIES 8.5 FINNED ANNULI 8.6 CONCLUSIONS 8.7 REFERENCES 8.8 NOMENCLATURE CHAPTER 9 INTEGRAL ROUGHNESS9.1 INTRODUCTION 9.2 ROUGHNESS WITH LAMINAR FLOW 9.3 HEAT-MOMENTUM TRANSFER ANALOGY CORRELATION Friction Similarity Law PEC Example 9.1 Heat Transfer Similarity Law Smooth Surfaces Rough Surfaces 9.4 TWO-DIMENSIONAL ROUGHNESS Transverse Rib Roughness Integral Helical-Rib Roughness Wire Coil Inserts Corrugated Tube Roughness PEC Example 9.2 9.5 THREE-DIMENSIONAL ROUGHNESS 9.6 PRACTICAL ROUGHNESS APPLICATIONSTubes with Inside Roughness Rod Bundles and Annuli Rectangular Channels Outside Roughness for Cross Flow 9.7 GENERAL PERFORMANCE CHARACTERISTICS St and f vs. Reynolds Number Other Correlating Methods Prandtl Number Dependence 9.8 HEAT TRANSFER DESIGN METHODS Design Method 1 Design Method 2 9.9 PREFERRED ROUGHNESS TYPE AND SIZE Roughness Type PEC Example 9.3 9.10 NUMERICAL SIMULATION Predictions for Transverse-Rib Roughness Effect of Rib Shape The Discrete-Element Predictive Model 9.11 CONCLUSIONS 9.12 REFERENCES 9.12 NOMENCLATURE CHAPTER 10: FOULING ON ENHANCED SURFACES10.1 INTRODUCTION 10.2 FOULING FUNDAMENTALS Particulate Fouling 10.3 FOULING OF GASES ON FINNED SURFACES 10.4 SHELL SIDE FOULING OF LIQUIDS Low Radial Fins Axial Fins and Ribs in Annulus Ribs in Rod Bundle 10.5 FOULING OF LIQUIDS IN INTERNALLY FINNED TUBES 10.6 LIQUID FOULING IN ROUGH TUBES Accelerated Fouling Long Term Fouling 10.7 LIQUID FOULING IN PLATE-FIN GEOMETRY 10.8 CORRELATIONS FOR FOULING IN ROUGH TUBES 10.9 MODELING OF FOULING IN ENHANCED TUBES 10.10 FOULING IN PLATE HEAT EXCHANGERS 10.11 CONCLUSIONS 10.12 REFERENCES 10.13 NOMENCLATURE CHAPTER 11 POOL BOILING11.1 INTRODUCTION 11.2 EARLY WORK ON ENHANCEMENT (1931-1962) 11.3 SUPPORTING FUNDAMENTAL STUDIES11.4 TECHNIQUES EMPLOYED FOR ENHANCEMENT Abrasive Treatment Open Grooves Three-Dimensional Cavities Etched Surfaces Electroplating Pierced Three-dimensional Cover Sheets Attached Wire and Screen Promoters Nonwetting Coatings Oxide and Ceramic Coatings Porous Surfaces Structured Surfaces (Integral Roughness) Combination Structured and Porous Surfaces Composite Surfaces 11.5 SINGLE-TUBE POOL BOILING TESTS OF ENHANCED SURFACES 11.6 THEORETICAL FUNDAMENTALS Liquid Superheat Effect of Cavity Shape and Contact Angle on Superheat Entrapment of Vapor in Cavities Effect of Dissolved Gases Nucleation at a Surface Cavity Bubble Departure Diameter Bubble Dynamics 11.7 BOILING HYSTERESIS AND ORIEN

Ralph L. Webb is a Professor Emeritus of Mechanical Engineering at the Pennsylvania State University. He received his Ph.D. from the University of Minnesota, and has published over 275 papers in the general area of heat transfer enhancement and has eight U.S. patents on enhanced heat transfer surfaces. He has performed research on enhanced heat transfer in boiling, condensation, fouling, air-cooled heat exchangers, electronic equipment cooling, forced convection for gases and liquids, wetting coatings to promote drainage of thin liquid films, and frost formation. Prof. Webb is the Founding Editor and Editor-in-Chief of the Journal of Enhanced Heat Transfer and is an editor of Heat Transfer Engineering journal. He is a recipient of the ASME Heat Transfer Memorial Award, the UK Refrigeration Institute Hall-Thermotank Gold Medal, and the AIChE Donald Q. Kern award. He is also a Fellow of ASME and ASHRAE and a Life Member of ASME. Nae-Hyun Kim is a Professor of Mechanical Engineering at the University of Incheon, Korea. He earned his Ph.D. at the Pennsylvania State University in 1989 under the supervision of Prof. Webb. Since then, he has been closely working with air-conditioning and refrigeration industries, where enhanced heat transfer technology has been successfully employed. Prof. Kim has published more than 30 international journal and conference papers related to boiling, condensation, fouling, and forced convection of liquids and gases. He is a member of ASME and ASHRAE.