2nd Edition
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.
1.1 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 FUNDAMENTALS
2.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 FLOWS
3.1 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 EXCHANGERS
4.1 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 SURFACES
5.1 INTRODUCTION
5.2 OFFSET-STRIP FIN
5.2.1 Enhancement Principle
5.2.2 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 Edges
5.3 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 TUBES
6.1 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 Spacing
Correlations 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 Tubes
Flat 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 Measurements
6.10 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 FLOW
7.1 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 ANNULI
8.1 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 ROUGHNESS
9.1 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 APPLICATIONS
Tubes 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 SURFACES
10.1 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 BOILING
11.1 INTRODUCTION
11.2 EARLY WORK ON ENHANCEMENT (1931-1962)
11.3 SUPPORTING FUNDAMENTAL STUDIES
11.4 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 ORIENTATION EFFECTS
Hysteresis Effects
Size and Orientation Effects
11.8 BOILING MECHANISM ON ENHANCED SURFACES
Basic Principles Employed
Visualization of Boiling in Subsurface Tunnels
Boiling Mechanism in Subsurface Tunnels
Chien and Webb Parametric Boiling Studies
11.9 PREDICTIVE METHODS FOR STRUCTURED SURFACES
Empirical Correlations
Nakayama et al. [1980b]
Chien and Webb Model
Ramaswamy et al. Model [2003]
Jiang et al. Model [2001]
Other Models
Evaluation of Models
11.10 BOILING MECHANISM ON POROUS SURFACES
O'Neill et al. Thin Film Concept
Kovalev et al. [1990] Concept
11.11 PREDICTIVE METHODS FOR POROUS SURFACES
O'Neill et al. [1972] Model
Kovalov et al. [1990] Model
Nishikawa et al. [1983] Correlation
Zhang and Zhang [1992] Correlation
11.12 CRITICAL HEAT FLUX
11.13 ENHANCEMENT OF THIN FILM EVAPORATION
11.14 CONCLUSIONS
11.15 REFERENCES
11.16 NOMENCLATURE
CHAPTER 12: VAPOR SPACE CONDENSATION
12.1 INTRODUCTION
Condensation Fundamentals
Basic Approaches to Enhanced Film Condensation
12.2 DROPWISE CONDENSATION
12.3 SURVEY OF ENHANCEMENT METHODS
Coated Surfaces
Roughness
Horizontal Integral-Fin Tubes
Corrugated Tubes
Surface Tension Drainage
Vertical Fluted Tubes
Electric Fields
12.4 SURFACE TENSION DRAINED CONDENSATION
Fundamentals
Adamek's Generalized Analysis
Practical Fin Profiles
Prediction for Trapezoidal Fin Shapes
12.5 HORIZONTAL INTEGRAL-FIN TUBE
The Beatty and Katz Model
Precise Surface Tension Drained Models
Approximate Surface Tension Drained Models
Comparison of Theory and Experiment
12.6 HORIZONTAL TUBE BANKS
Condensate Inundation without Vapor Shear
Condensate Drainage Pattern
Prediction of the Condensation Coefficient
12.7 CONCLUSIONS
12.8 REFERENCES
12.9 NOMENCLATURE
APPENDIX A: THE KEDZIERSKI AND WEBB [1990] FIN PROFILE SHAPES
APPENDIX B: FIN EFFICIENCY IN THE FLOODED REGION
CHAPTER 13 CONVECTIVE VAPORIZATION
13.1 INTRODUCTION
13.2 FUNDAMENTALS
Flow Patterns
Convective Vaporization in Tubes
Two-Phase Pressure Drop
Effect of Flow Orientation on Flow Pattern
Convective Vaporization in Tube Bundles
Critical Heat Flux
13.3 ENHANCEMENT TECHNIQUES IN TUBES
Internal Fins
Swirl Flow Devices
Roughness
Coated Surfaces
Perforated Foil Inserts
Porous Media
Coiled Tubes and Return Bends
13.4 THE MICROFIN TUBE
Early Work on the Microfin Tube
Recent Work on the Microfin Tube
Special Microfin Geometries
Microfin Vaporization Data
13.5 MINI-CHANNELS
13.6 CRITICAL HEAT FLUX (CHF)
Twisted Tape
Grooved Tubes
Mesh Inserts
13.7 PREDICTIVE METHODS FOR IN-TUBE FLOW
High Internal Fins
Microfins
Twisted Tape Inserts
Corrugated Tubes
Porous Coatings
13.8 TUBE BUNDLES
Convective Effects in Tube Bundles
Starting Hysteresis in Tube Bundles
13.9 PLATE-FIN HEAT EXCHANGERS
13.10 THIN FILM EVAPORATION
Horizontal Tubes
Vertical Tubes
13.11 CONCLUSIONS
13.12 REFERENCES
CHAPTER 14: CONVECTIVE CONDENSATION
14.1 INTRODUCTION
14.2 FORCED CONDENSATION INSIDE TUBES
Internally Finned Tubes
Twisted-tape Inserts.
Roughness
Coiled Tubes and Return Bends
14.3 MICROFIN TUBE
Microfin Geometry Details
Optimization of Internal Geometry
Condensation Mechanism in Microfin Tubes
Convective Condensation in Special Microfin Geometries
14.4 FLAT TUBE AUTOMOTIVE CONDENSERS
Condensation Data for Flat, Extruded Tubes
Other Predictive Methods of Condensation in Flat Tubes
14.5 PLATE-TYPE HEAT EXCHANGERS
14.6 NON-CONDENSIBLE GASES
14.7 PREDICTIVE METHODS FOR CIRCULAR TUBES
High Internal Fins
Wire Loop Internal Fins
Twisted-tapes
Roughness
Microfins
14.8 CONCLUSIONS
14.8 REFERENCES
14.9 NOMENCLATURE
CHAPTER 15 ENHANCEMENT USING ELECTRIC FIELDS
15.1 INTRODUCTION
15.2 ELECTRODE DESIGN AND PLACEMENT
15.3 SINGLE-PHASE FLUIDS
15.3.1 Enhancement on Gas Flow
15.3.2 Enhancement on Liquid Flow
15.3.3 Numerical Studies
15.4 CONDENSATION
15.4.1 Fundamental Understanding
15.4.2 Vapor Space Condensation
15.4.3 In-tube Condensation
15.4.4 Falling Film Evaporation
15.4.5 Correlations
15.5 BOILING
15.5.1 Fundamental Understanding
15.5.2 Pool Boiling
15.5.3 Convective Vaporization
15.5.4 Critical Heat Flux
15.5.5 Correlations
15.6 CONCLUSIONS
15.7 REFERENCES
15.8 NOMENCLATURE
CHAPTER 16: SIMULTANEOUS HEAT AND MASS TRANSFER
16.1 INTRODUCTION
16.2 MASS TRANSFER RESISTANCE IN THE GAS PHASE
Condensation with Noncondensible Gases
Evaporation into Air
Dehumidifying Finned-Tube Heat Exchangers
Water Film Enhancement of Finned Tube Exchanger
16.3 CONTROLLING RESISTANCE IN LIQUID PHASE
16.4 SIGNIFICANT RESISTANCE IN BOTH PHASES
16.5 CONCLUSIONS
16.6 REFERENCES
16.7 NOMENCLATURE
CHAPTER 17 ADDITIVES FOR GASES AND LIQUIDS
17.1 INTRODUCTION
17.2 ADDITIVES FOR SINGLE-PHASE LIQUIDS
Solid Particles
PEC Example
Gas Bubbles
Suspensions in Dilute Polymer and Surfactant Solutions
17.3 ADDITIVES FOR SINGLE-PHASE GASES
Solid Additives
Liquid Additives
17.4 ADDITIVES FOR BOILING
17.5 ADDITIVES FOR CONDENSATION
17.6 CONCLUSIONS
17.7 REFERENCES
17.8 NOMENCLATURE
CHAPTER 18 MICRO-CHANNELS
18.1 INTRODUCTION
18.2 FRICTION IN SINGLE MICRO-CHANNELS
18.3 FRICTION IN A SINGLE CHANNEL VS. MULTI-CHANNELS
18.4 SINGLE-PHASE HEAT TRANSFER IN MICRO-CHANNELS
18.4.1 Single Channel Flow
18.4.2 Heat Transfer in Multiple Micro-channels
18.5 MANIFOLD SELECTION AND DESIGN
18.5.1 Single-Phase Flow
18.5.2 Two-Phase Flow
18.6 NUMERICAL SIMULATION OF FLOW IN MANIFOLDS
18.7 TWO-PHASE HEAT TRANSFER IN MICRO-CHANNELS
18.8 CONCLUSIONS
18.9 REFERENCES
18.10 NOMENCLATURE
CHAPTER 19 ELECTRONIC COOLING HEAT TRANSFER
19.1 INTRODUCTION
19.2 COMPONENT THERMAL RESISTANCES
19.3 LIMITS ON DIRECT HEAT REMOVAL WITH AIR-COOLING (DirHR)
19.3.1 PEC Example 19.1 Enhanced Fin Geometry Heat Sink
Table 19.1 Performance Of Plain Fin And Offset Strip Fin Heat Sinks.
19.4 2nd GENERATION IndHR DEVICES FOR HEAT REMOVAL AT HOT SOURCE
19.4.1 Single-Phase Fluids
19.4.2 Two-Phase Fluids
19.4.3 Heat Pipe
19.4.4 Nucleate Boiling
19.4.5 Forced Convection
19.4.6 Spray Cooling
19.5 DISCUSSION OF ADVANCED HEAT REMOVAL CONCEPTS
19.5.1 Jet Impingement/Spray Cooling Devices
19.5.2 Single-Phase Micro-Channel Cooling
19.5.3 Two-Phase Micro-Channel Cooling
19.5.4 Enhanced Two-Phase Forced Convection Cooling
19.6 REMOTE HEAT-EXCHANGERS FOR IndHR
19.6.1 Air-Cooled Ambient Heat-Exchangers
19.6.2 Condensing Surfaces
19.6.3 Design for Multiple Heat Sources
19.7 SYSTEM PERFORMANCE FOR THE IndHR SYSTEM
19.8 CONCLUSIONS
19.9 REFERENCES
19.10 NOMENCLATURE
PROBLEM SUPPLEMENT
INDEX
Biography
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.