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NTU method

About: NTU method is a research topic. Over the lifetime, 3296 publications have been published within this topic receiving 63832 citations. The topic is also known as: Number of transfer units & The NTU.


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MonographDOI
25 Jul 2003
TL;DR: In this paper, the authors present a classification of Heat Exchanger design according to the number of fluids and their properties, such as surface heat transfer, flow arrangement, and number of transfer units.
Abstract: Preface. Nomenclature. 1 Classification of Heat Exchangers. 1.1 Introduction. 1.2 Classification According to Transfer Processes. 1.3 Classification According to Number of Fluids. 1.4 Classification According to Surface Compactness. 1.5 Classification According to Construction Features. 1.6 Classification According to Flow Arrangements. 1.7 Classification According to Heat Transfer Mechanisms. Summary. References. Review Questions. 2 Overview of Heat Exchanger Design Methodology. 2.1 Heat Exchanger Design Methodology. 2.2 Interactions Among Design Considerations. Summary. References. Review Questions. Problems. 3 Basic Thermal Design Theory for Recuperators. 3.1 Formal Analogy between Thermal and Electrical Entities. 3.2 Heat Exchanger Variables and Thermal Circuit. 3.3 The ?(Epsilon)-NTU Method. 3.4 Effectiveness - Number of Transfer Unit Relationships. 3.5 The P-NTU Method. 3.6 P-N TU R elat ionships. 3.7 The Mean Temperature Difference Method. 3.8 F Factors for Various Flow Arrangements. 3.9 Comparison of the ?(Epsilon)-NTU, P-NTU, and MTD Methods. 3.10 The ?(Psi)-P and P1-P2 Methods. 3.11 Solution Methods for Determining Exchanger Effectiveness. 3.12 Heat Exchanger Design Problems. Summary. References. Review Questions. Problems. 4 Additional Considerations for Thermal Design of Recuperators. 4.1 Longitudinal Wall Heat Conduction Effects. 4.2 Nonuniform Overall Heat Transfer Coefficients. 4.3 Additional Considerations for Extended Surface Exchangers. 4.4 Additional Considerations for Shell-and-Tube Exchangers. Summary. References. Review Questions. Problems. 5 Thermal Design Theory for Regenerators. 5.1 Heat Transfer Analysis. 5.2 The ?(Epsilon)-NTUo Method. 5.3 The ?(Lambda)-?(Pi) Method. 5.4 Influence of Longitudinal Wall Heat Conduction. 5.5 Influence of Transverse Wall Heat Conduction. 5.6 Influence of Pressure and Carryover Leakages. 5.7 Influence of Matrix Material, Size, and Arrangement. Summary. References. Review Questions. Problems. 6 Heat Exchanger Pressure Drop Analysis. 6.1 Introduction. 6.2 Extended Surface Heat Exchanger Pressure Drop. 6.3 Regenerator Pressure Drop. 6.4 Tubular Heat Exchanger Pressure Drop. 6.5 Plate Heat Exchanger Pressure Drop. 6.6 Pressure Drop Associated with Fluid Distribution Elements. 6.7 Pressure Drop Presentation. 6.8 Pressure Drop Dependence on Geometry and Fluid Properties. Summary. References. Review Questions. Problems. 7 Surface Basic Heat Transfer and Flow Friction Characteristics. 7.1 Basic Concepts. 7.2 Dimensionless Groups. 7.3 Experimental Techniques for Determining Surface Characteristics. 7.4 Analytical and Semiempirical Heat Transfer and Friction Factor Correlations for Simple Geometries. 7.5 Experimental Heat Transfer and Friction Factor Correlations for Complex Geometries. 7.6 Influence of Temperature-Dependent Fluid Properties. 7.7 Influence of Superimposed Free Convection. 7.8 Influence of Superimposed Radiation. Summary. References. Review Questions. Problems. 8 Heat Exchanger Surface Geometrical Characteristics. 8.1 Tubular Heat Exchangers. 8.2 Tube-Fin Heat Exchangers. 8.3 Plate-Fin Heat Exchangers. 8.4 Regenerators with Continuous Cylindrical Passages. 8.5 Shell-and-Tube Exchangers with Segmental Baffles. 8.6 Gasketed Plate Heat Exchangers. Summary. References. Review Questions. 9 Heat Exchanger Design Procedures. 9.1 Fluid Mean Temperatures. 9.2 Plate-Fin Heat Exchangers. 9.3 Tube-Fin Heat Exchangers. 9.3.4 Core Mass Velocity Equation. 9.4 Plate Heat Exchangers. 9.5 Shell-and-Tube Heat Exchangers. 9.6 Heat Exchanger Optimization. Summary. References. Review Questions. Problems. 10 Selection of Heat Exchangers and Their Components. 10.1 Selection Criteria Based on Operating Parameters. 10.2 General Selection Guidelines for Major Exchanger Types. 10.3 Some Quantitative Considerations. Summary. References. Review Questions. Problems. 11 Thermodynamic Modeling and Analysis. 11.1 Introduction. 11.2 Modeling a Heat Exchanger Based on the First Law of Thermodynamics. 11.3 Irreversibilities in Heat Exchangers. 11.4 Thermodynamic Irreversibility and Temperature Cross Phenomena. 11.5 A Heuristic Approach to an Assessment of Heat Exchanger Effectiveness. 11.6 Energy, Exergy, and Cost Balances in the Analysis and Optimization of Heat Exchangers. 11.7 Performance Evaluation Criteria Based on the Second Law of Thermodynamics. Summary. References. Review Questions. Problems. 12 Flow Maldistribution and Header Design. 12.1 Geometry-Induced Flow Maldistribution. 12.2 Operating Condition-Induced Flow Maldistribution. 12.3 Mitigation of Flow Maldistribution. 12.4 Header and Manifold Design. Summary. References. Review Questions. Problems. 13 Fouling and Corrosion. 13.1 Fouling and its Effect on Exchanger Heat Transfer and Pressure Drop. 13.2 Phenomenological Considerations of Fouling. 13.3 Fouling Resistance Design Approach. 13.4 Prevention and Mitigation of Fouling. 13.5 Corrosion in Heat Exchangers. Summary. References. Review Questions. Problems. Appendix A: Thermophysical Properties. Appendix B: ?(Epsilon)-NTU Relationships for Liquid-Coupled Exchangers. Appendix C: Two-Phase Heat Transfer and Pressure Drop Correlations. C.1 Two-Phase Pressure Drop Correlations. C.2 Heat Transfer Correlations for Condensation. C.3 Heat Transfer Correlations for Boiling. Appendix D: U and CUA Values for Various Heat Exchangers. General References on or Related to Heat Exchangers. Index.

2,006 citations

Book
29 Dec 1997
TL;DR: In this paper, the effect of variable physical properties in Turbulent Forced Convection in Smooth Straight Noncircular Ducts and Turbulents Flow in smooth Straight Non-circular ducts is discussed.
Abstract: CLASSIFICATIONS OF HEAT EXCHANGERS Introduction Recuperation and Regeneration Transfer Processes Geometry of Construction Heat Transfer Mechanisms Flow Arrangements Applications Selection of Heat Exchangers BASIC DESIGN METHODS OF HEAT EXCHANGERS Introduction Arrangement of Flow Path in Heat Exchangers Basic Equations in Design Overall Heat Transfer Coefficient The LMTD Method for Heat Exchangers Analysis The e-NTU Method for Heat Exchangers Analysis Heat Exchanger Design Calculation Variable Overall Heat Transfer Coefficient Heat Exchanger Design Methodology FORCED CONVECTION CORRELATIONS FOR SINGLE-PHASE SIDE OF HEAT EXCHANGERS Introduction Laminar Forced Convection The Effect of Variable Physical Properties Turbulent Forced Convection Turbulent Flow in Smooth Straight Noncircular Ducts The Effect of Variable Physical Properties in Turbulent Forced Convection Summary of Forced Convection in Straight Ducts Heat Transfer from Smooth-Tube Bundles Heat Transfer in Helical Coils and Spirals Heat Transfer in Bends HEAT EXCHANGER PRESSURE DROP AND PUMPING POWER Introduction Tube-Side Pressure Drop Pressure Drop in Tube Bundles in Cross-Flow Pressure Drop in Helical and Spiral Coils Pressure Drop in Bends and Fittings Pressure Drop for Abrupt Contraction, Expansion, and Momentum Change Heat Transfer and Pumping Power Relationship FOULING OF HEAT EXCHANGERS Introduction Basic Considerations Effects of Fouling Aspects of Fouling Design of Heat Exchangers Subject to Fouling Operation of Heat Exchangers Subject to Fouling Techniques to Control Fouling DOUBLE-PIPE HEAT EXCHANGERS Introduction Thermal and Hydraulic Design of Inner Tube Thermal and Hydraulic Analysis of Annulus Parallel-Series Arrangements of Hairpins Total Pressure Drop Design and Operational Features DESIGN CORRELATIONS FOR CONDENSERS AND EVAPORATORS Introduction Condensation Film Condensation on a Single Horizontal Tube Film Condensation on Tube Bundles Condensation Inside Tubes Flow Boiling SHELL-AND-TUBE HEAT EXCHANGERS Introduction Basic Components Basic Design Procedure of a Heat Exchanger Shell-Side Heat Transfer and Pressure Drop COMPACT HEAT EXCHANGERS Introduction Heat Transfer and Pressure Drop THE GASKETED-PLATE HEAT EXCHANGERS Introduction Mechanical Features Operational Characteristics Passes and Flow Arrangements Applications Heat Transfer and Pressure Drop Calculations Thermal Performance CONDENSERS AND EVAPORATORS Introduction Shell and Tube Condensers Steam Turbine Exhaust Condensers Plate Condensers Air Cooled Condensers Direct Contact Condensers Thermal Design of Shell-and-Tube Condensers Design and Operational Considerations Condensers for Refrigeration and Air Conditioning Evaporators for Refrigeration and Air Conditioning Thermal Analysis Standards for Evaporators and Condensers APPENDICES Physical Properties of Metals and Nonmetals Physical Properties of Air, Water, Liquid Metals, and Refrigerants Each chapter also contains sections of Nomenclature, References, and Problems

1,120 citations

Book
20 Oct 1995
TL;DR: In this paper, the three-part structure of Heat Exchanger Irreversibility has been studied in the context of solar-thermal power generation, showing that the three parts of the structure of a two-phase-flow heat exchanger can be used to estimate the entropy generation rate.
Abstract: List of Symbols Thermodynamics Concepts and Laws Definitions Closed Systems Open Systems The Momentum Theorem Useful Steps in Problem Solving The Temperature-Energy Interaction Diagram, and the Entropy Interaction-Energy Interaction Diagram Problems Entropy Generation and Exergy Destruction The Gouy-Stodola Theorem Systems Communicating with More than One Heat Reservoir Adiabatic Systems Exergy Analysis of Steady Flow Processes Exergy Analysis of Non-Flow Processes Characteristic Features of Irreversible Systems and Processes Problems Entropy Generation in Fluid Flow Relationship between Entropy Generation and Viscous Dissipation Laminar Flow Turbulent Flow The Transition Buckling Theory of Turbulent Flow Entropy Generation in "Isothermal" Turbulent Flow The Bernoulli Equation Entropy Generation in Heat Transfer The Local Rate of Entropy Generation in Convective Heat Transfer Fluid Friction vs. Heat Transfer Irreversibility Internal Flows External Flows Conduction Heat Transfer Convective Mass Transfer General Heat Exchanger Passage Heat Transfer Augmentation Techniques Problems Heat Exchangers Counterflow Heat Exchangers Heat Exchangers with Negligible Pressure Drop Irreversibility The Three-Part Structure of Heat Exchanger Irreversibility Two-Phase-Flow Heat Exchangers Other Heat Exchanger Entropy Generation Studies Distribution of Heat Exchanger Area on the Absolute Temperature Scale Distribution of Heat Transfer Area in Counterflow Heat Exchangers Problems Insulation Systems Power Plants and Refrigeration Plants as Insulation Systems The Generation of Entropy in an Insulation with Fixed Geometry Optimum Continuous Cooling Regime Counterflow Heat Exchangers as One-Dimensional Insulations Parallel Insulations Intermediate Cooling or Heating of Insulation Systems for Power and Refrigeration Plants Problems Storage Systems Sensible Heat Storage Optimum Heating and Cooling Processes Subject to Time Constraint Hot Storage vs. Cold Storage Latent Heat Storage Power Generation Model with Bypass Heat Leak and Two Finite-Size Heat Exchangers Power Plant Viewed as an Insulation Between Heat Source and Ambient Combined-Cycle Power Plant Optimal Combustion Chamber Temperature Other Power Plant Optimization Studies Why Maximum Power Means Minimum Entropy Generation Rate Maximum Power from Fluid Flow Problems Solar-Thermal Power Generation Models with Collector Heat Loss to the Ambient Collector-Ambient Heat Loss and Collector-Engine Heat Exchanger Collector-Ambient Heat Loss and Engine-Ambient Heat Exchanger Storage by Melting Extraterrestrial Solar Power Plant Nonisothermal Collectors Time-Varying Conditions Other Areas of Solar Power Conversion Study Problems Refrigeration Refrigeration Plant Model with Heat Transfer Irreversibilities Model with Heat Leak in Parallel with Reversible Compartment Model with Cold End Heat Exchanger and Room Temperature Heat Exchanger Minimization of the Heat-Leak Entropy Generation Problems Time-Dependent Operation Defrosting Refrigerators Cleaning the Heat Exchanger of a Power Plant Power Plants Driven by Heating from a Bed of Hot Dry Rock Maximum Rate of Ice Production Problems Appendices Local Entropy Generation Rate Variational Calculus Author Index Subject Index

665 citations

Journal ArticleDOI
TL;DR: In this paper, an analytical model is developed for model foams with simple cubic unit cells consisting of heated slender cylinders, based on existing heat transfer data on convective crossflow through cylinder banks.

558 citations

Journal ArticleDOI
TL;DR: In this article, a small circular channel (d = 2.46) and a small rectangular channel with Refrigerant 12.5 was used to study the effects of channel geometry and fluid properties on heat transfer.

545 citations


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No. of papers in the topic in previous years
YearPapers
202330
202269
202122
202028
201925
201843