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Beskrivning
Whether in a solar thermal power plant or at the heart of a nuclear reactor, convection is an important mode of energy transfer. This mode is unique; it obeys specific rules and correlations that constitute one of the bases of equipment-sizing equations. In addition to standard aspects of convention, this book examines transfers at very high temperatures where, in order to ensure the efficient transfer of energy for industrial applications, it is becoming necessary to use particular heat carriers, such as molten salts, liquid metals or nanofluids. With modern technologies, these situations are becoming more frequent, requiring appropriate consideration in design calculations. Energy Transfers by Convection also studies the sizing of electronic heat sinks used to ensure the dissipation of heat and thus the optimal operation of circuit boards used in telecommunications, audio equipment, avionics and computers.
Produktinformation
- Utgivningsdatum:2019-01-11
- Mått:163 x 234 x 31 mm
- Vikt:771 g
- Format:Inbunden
- Språk:Engelska
- Antal sidor:432
- Förlag:ISTE Ltd and John Wiley & Sons Inc
- ISBN:9781786302762
Utforska kategorier
Mer om författaren
Abdelhanine Benallou, Professor of higher education for more than 30 years, has led companies in the fields of renewable energy, the rational use of energy, decentralized rural electrification and environmental protection.
Innehållsförteckning
- Preface xiIntroduction xiiiChapter 1 Methods for Determining Convection Heat Transfer Coefficients 11.1 Introduction 11.2 Characterizing the motion of a fluid 11.3 Transfer coefficients and flow regimes 31.4 Using dimensional analysis 41.4.1 Dimensionless numbers used in convection 41.4.2 Dimensional analysis applications in convection 71.5 Using correlations to calculate h 121.5.1 Correlations for flows in forced convection 141.5.2 Correlations for flows in natural convection 14Chapter 2 Forced Convection Inside Cylindrical Pipes 152.1 Introduction 152.2 Correlations in laminar flow 152.2.1 Reminders regarding laminar-flow characteristics inside a pipe 162.2.2 Differential energy balance 172.2.3 Illustration: transportation of phosphate slurry in a cylindrical pipe 222.2.4 Correlations for laminar flow at pipe entrance 252.3 Correlations in transition zone 302.4 Correlations in turbulent flow 302.4.1 Dittus–Boelter–McAdams relation. 312.4.2 Colburn–Seider–Tate relation 322.4.3 Illustration: improving transfer by switching to turbulent flow 332.4.4 Specific correlations in turbulent flow 342.4.5 Illustration: industrial-grade cylindrical pipe 382.5 Dimensional correlations for air and water 39Chapter 3 Forced Convection Inside Non-Cylindrical Pipes 433.1 Introduction 433.2 Concept of hydraulic diameter. 433.3 Hydraulic Nusselt and Reynolds numbers 453.4 Correlations in established laminar flow 453.4.1 Pipes with rectangular or square cross-sections in laminar flow 453.4.2 Pipes presenting an elliptical cross-section in laminar flow 463.4.3 Pipes presenting a triangular cross-section in laminar flow 473.4.4 Illustration: air-conditioning duct design 483.4.5 Annular pipes with laminar flow 513.5 Correlations in turbulent flow for non-cylindrical pipes 573.5.1 Pipes with rectangular or square cross-sections in turbulent flow 573.5.2 Pipes with elliptical or triangular cross-sections in turbulent flow 583.5.3 Illustration: design imposes the flow regime 603.5.4 Annular pipes in turbulent flow 62Chapter 4 Forced Convection Outside Pipes or Around Objects 694.1 Introduction 694.2 Flow outside a cylindrical pipe 704.3 Correlations for the stagnation region 714.4 Correlations beyond the stagnation zone 724.5 Forced convection outside non-cylindrical pipes 724.5.1 Pipes with a square cross-section area 724.5.2 Pipes presenting an elliptical cross-section area 744.5.3 Pipes presenting a hexagonal cross-section area 744.6 Forced convection above a horizontal plate 764.6.1 Plate at constant temperature 764.6.2 Plate with constant flow density 774.7 Forced convection around non-cylindrical objects 794.7.1 Forced convection around a plane parallel to the flow 794.7.2 Forced convection around a sphere 804.8 Convective transfers between falling films and pipes 804.8.1 Vertical tubes 814.8.2 Horizontal tubes 824.9 Forced convection in coiled pipes 834.9.1 Convection heat transfer coefficient inside the coil 844.9.2 Convection heat transfer coefficient with the outer wall of the coil 854.9.3 Convection heat transfer coefficient between the fluid and the tank 87Chapter 5 Natural Convection Heat Transfer 895.1 Introduction 895.2 Characterizing the motion of natural convection 895.3 Correlations in natural convection 915.4 Vertical plates subject to natural convection 925.5 Inclined plates subject to natural convection 945.6 Horizontal plates subject to natural convection 955.6.1 Case of underfloor heating 955.6.2 Ceiling cooling systems 965.7 Vertical cylinders subject to natural convection 975.8 Horizontal cylinders subject to natural convection 985.9 Spheres subject to natural convection 995.10 Vertical conical surfaces subject to natural convection 1005.11 Any surface subject to natural convection 1015.12 Chambers limited by parallel surfaces 1015.12.1 Correlation of Hollands et al. for horizontal chambers 1035.12.2 Correlation of El-Sherbiny et al. for vertical chambers 1045.13 Inclined-plane chambers 1055.13.1 For large aspect ratios and low-to-moderate inclinations 1055.13.2 For lower aspect ratios and inclinations below the critical inclination 1065.13.3 For lower aspect ratios and inclinations greater than the critical inclination 1065.14 Chambers limited by two concentric cylinders 1075.15 Chambers limited by two concentric spheres 1095.16 Simplified correlations for natural convection in air 1115.16.1 Vertical cylinder or plane under natural convection in air 1115.16.2 Horizontal cylinder or plane under natural convection in air. 1115.16.3 Horizontal plane under natural convection in air 1125.16.4 Sphere under natural convection in air 1125.16.5 Circuit boards under natural convection in air 1125.16.6 Electronic components or cables under natural convection in air 1135.17 Finned surfaces: heat sinks in electronic systems 1135.17.1 Dissipation systems 1145.17.2 Thermal resistance of a heat sink 1155.18 Optimizing the thermal resistance of a heat sink 1175.18.1 Determining the heat-sink/air heat transfer coefficient 1195.18.2 Calculating the optimum spacing between fins 1205.18.3 Practical expression 1205.18.4 Calculating the evacuated heat flux 1205.18.5 Implementation algorithm 1205.18.6 Illustration: optimum design of a heat sink 1225.19 Optimum circuit-board assembly 1255.19.1 Calculating the optimum spacing between electronic boards 1265.19.2 Heat transfer coefficient between electronic boards and air 1265.19.3 Calculating the evacuated heat flux 1275.19.4 Implementation algorithm 1275.19.5 Illustration: optimum evacuation of heat generated by electronic boards 1295.20 Superimposed forced and natural convections 1305.20.1 Vertical-tube scenario: Martinelli-Boelter correlation 1315.20.2 Horizontal-tube scenario: Proctor-Eubank correlation 1325.20.3 Cylinders, disks or spheres in rotation 133Chapter 6 Convection in Nanofluids, Liquid Metals and Molten Salts 1376.1 Introduction 1376.2 Transfers in nanofluids 1386.2.1 Physical data 1396.2.2 Nanofluids circulating in tubes 1426.2.3 Nanofluids circulating within annular pipes 1446.2.4 Superposition of natural and forced convections in nanofluids 1456.3 Transfers in liquid metals 1466.3.1 Physical data 1466.3.2 Liquid metals in forced convection within cylindrical pipes 1476.3.3 Liquid metals in forced convection within an annular space 1476.3.4 Liquid metals flowing along a horizontal plane 1496.3.5 Liquid metals in forced convection between two parallel planes 1496.3.6 Liquid metals subject to natural convection 1496.4 Transfers in molten salts 1506.4.1 Physical data 1506.4.2 Molten salts under forced convection in laminar flow within cylindrical pipes 1516.4.3 Molten salts under forced convection in the transition zone within cylindrical pipes 1526.4.4 Molten salts under forced convection in turbulent flow within cylindrical pipes 1536.5 Reading: Eugène Péclet and Lord Rayleigh 1546.5.1 Eugène Péclet 1546.5.2 Lord Rayleigh 155Chapter 7 Exercises and Solutions 157Appendices 321Appendix 1 Database 323Appendix 2 Regressions 385Bibliography 389Index 403