Skip to main content
main-content

Über dieses Buch

The book provides design engineers an elemental understanding of the variables that influence pressure drop and heat transfer in plain and micro-fin tubes to thermal systems using liquid single-phase flow in different industrial applications. It also provides design engineers using gas-liquid, two-phase flow in different industrial applications the necessary fundamentals of the two-phase flow variables. The author and his colleagues were the first to determine experimentally the very important relationship between inlet geometry and transition. On the basis of their results, they developed practical and easy to use correlations for the isothermal and non-isothermal friction factor (pressure drop) and heat transfer coefficient (Nusselt number) in the transition region as well as the laminar and turbulent flow regions for different inlet configurations and fin geometry. This work presented herein provides the thermal systems design engineer the necessary design tools. The author further presents a succinct review of the flow patterns, void fraction, pressure drop and non-boiling heat transfer phenomenon and recommends some of the well scrutinized modeling techniques.

Inhaltsverzeichnis

Frontmatter

Single-Phase Flow Pressure Drop and Heat Transfer in Tubes

Frontmatter

Chapter 1. Introduction

Abstract
This chapter provides a brief background on the need for single-phase flow study in the transition region and a detailed overview of the pioneering research done by Professor Ghajar and his students over a period of three decades.
Afshin J. Ghajar

Chapter 2. Single-Phase Flow Experimental Setup for Plain and Micro-fin Tubes

Abstract
This chapter provides the details of a unique experimental setup that provides detailed information on the effect of entrance flow, buoyancy (secondary flow), inlet configurations (square-edged, re-entrant, and bell-mouth), and fin geometries (spiral angle, fin height-to-diameter ratio, and number of starts) on friction factor (isothermal and non-isothermal) and heat transfer in the entrance and fully developed regions of horizontal plain and micro-fin tubes in all flow regions (laminar, transitional, and turbulent).
Afshin J. Ghajar

Chapter 3. Effect of Inlet Configuration and Heating on Plain Tube Friction Factor

Abstract
Using the experimental setup detailed in Chap. 2, this chapter presents isothermal and non-isothermal (heating) friction factor results in the entrance and fully developed regions of the plain tube, the effect of inlet configuration (square-edged and re-entrant) on heat transfer modes (forced and mixed convection) and on the start and end of transition of the fully developed friction factor, the effect of inlet configuration and heating on the entrance and fully developed friction factors in all flow regimes, a discussion of the role of inlet configuration and heating, and the effect of entrance flow on pressure drop.
Afshin J. Ghajar

Chapter 4. Proposed Correlations for Laminar and Transition Friction Factors in Plain Tubes with Different Inlet Configurations

Abstract
Using the experimental data presented in Chap. 3, this chapter presents the developed accurate friction factor correlations for the laminar and transitional friction factors in the entrance and fully developed regions of plain tubes under isothermal and non-isothermal (heating) conditions and different inlet configurations (square-edged and re-entrant). At the conclusion of this chapter, an illustrative example is presented to demonstrate the use of the proposed correlations.
Afshin J. Ghajar

Chapter 5. Heat Transfer Results in Plain Tubes with Different Inlet Configurations

Abstract
Using the experimental setup detailed in Chap. 2, this chapter presents heat transfer results in the entrance and fully developed regions of the plain tube across all flow regimes (laminar, transitional, and turbulent). The effect of inlet configuration (square-edged, re-entrant, and bell-mouth) and buoyancy on heat transfer in different flow regimes is presented in this chapter. In addition, the variation of local Nusselt number along the tube in the laminar, transitional, and turbulent regions is discussed. In particular the unusual variation of local heat transfer coefficient in a circular tube with a bell-mouth inlet is highlighted.
Afshin J. Ghajar

Chapter 6. Proposed Correlations and Flow Regime Map for Laminar, Transition, and Turbulent Heat Transfer in Plain Tubes with Different Inlet Configurations

Abstract
Using the experimental data presented in Chap. 3, this chapter presents the developed accurate heat transfer correlations for the laminar, transitional, and turbulent dimensionless heat transfer coefficients (Nusselt number) in the entrance and fully developed regions of plain tubes under uniform wall heat flux boundary condition and different inlet configurations (square-edged and re-entrant). The proposed correlations were used to develop a flow regime map. The flow regime map provided in this study can be used to assist the heat exchanger designer in determining the influence of buoyancy in a horizontal circular tube with uniform wall heat flux boundary condition for a specified inlet configuration for all flow regimes. For the identified pure or mixed convection heat transfer regimes, heat transfer calculations can be made based on the recommended correlations. In addition, an illustrative example is presented to demonstrate the use of the proposed correlations.
Afshin J. Ghajar

Chapter 7. Friction Factor Results for Micro-fin Tubes

Abstract
Using the experimental setup detailed in Chap. 2, this chapter presents isothermal and non-isothermal (heating) friction factor results in the entrance and fully developed regions of the micro-fin tubes, the effect of inlet configuration and heating on the entrance and fully developed friction factors in all flow regimes (laminar, transitional, and turbulent), the effect of inlet configuration (square-edged and re-entrant) on the start and end of transition of the fully developed friction factor, and the effect of fin geometries (spiral angle, fin height-to-diameter ratio, and number of starts) on friction factors.
Afshin J. Ghajar

Chapter 8. Proposed Correlations for Laminar, Transition, and Turbulent Friction Factors in Micro-fin Tubes with Different Inlet Configurations

Abstract
Using the experimental data presented in Chap. 7, this chapter presents the developed accurate friction factor correlations for the laminar and transitional friction factors in the entrance and fully developed regions of micro-fin tubes under isothermal and non-isothermal (heating) conditions, different inlet configurations (square-edged and re-entrant), and different fin geometries (spiral angle, fin height-to-diameter ratio, and number of starts). For the fully developed turbulent region, the correlation of Jensen and Vlakancic (Int J Heat Mass Transfer 42:1343–1351, 1999) was recommended.
Afshin J. Ghajar

Chapter 9. Heat Transfer Results in Micro-fin Tubes

Abstract
Using the experimental setup detailed in Chap. 2, this chapter presents heat transfer results in the entrance and fully developed regions of the micro-fin tubes, the effect of inlet configuration (square-edged and re-entrant) and buoyancy on the entrance and fully developed heat transfer in all flow regimes (laminar, transitional, and turbulent), the effect of inlet configuration on the start and end of transition of the fully developed heat transfer, and the effect of fin geometries (spiral angle, fin height-to-diameter ratio, and number of starts) on heat transfer.
Afshin J. Ghajar

Chapter 10. Proposed Correlations for Laminar, Turbulent, and Transition Heat Transfer in Micro-fin Tubes with Different Inlet Configurations

Abstract
Using the experimental data presented in Chap. 9, this chapter presents the developed accurate heat transfer correlations for the laminar, transitional, and turbulent dimensionless heat transfer coefficients (Nusselt number) in the entrance and fully developed regions of micro-fin tubes under uniform wall heat flux boundary condition, different inlet configurations (square-edged and re-entrant), and different fin geometries (spiral angle, fin height-to-diameter ratio, and number of starts).
Afshin J. Ghajar

Chapter 11. Friction Factor in the Transition Region of Mini- and Micro-tubes

Abstract
This chapter presents the details of the experimental setup used for the study of the pressure drop measurements in 12 stainless steel mini- and micro-tubes ranging in diameter from 2083 to 337 μm over a wide range of Reynolds numbers from laminar to the turbulent region, and the start and end of the transition region in these small sized tubes. At the conclusion of this chapter, a brief summary of several studies that extends the work of Ghajar et al. (Heat Transfer Eng 31(8):646–657, 2010) is presented. These studies deal with topics such as: simultaneous heat transfer and pressure drop measurements in micro-tubes, effect of inner surface roughness and heating on friction factor of mini- to micro-tubes, heat transfer enhancement in mini-tubes, effect of straight and bending inlets with different angles (90° and 180° bend) installed before the test tube on heat transfer in mini- and micro-tubes, and the critical diameter for the onset of mixed convection in macro- and mini-tubes in the laminar region.
Afshin J. Ghajar

Two-Phase Flow Pressure Drop and Heat Transfer in Tubes

Frontmatter

Chapter 12. Introduction

Abstract
This chapter provides a brief background on two-phase flow, the need for two-phase flow study in inclined systems, and basic definitions of interest in two-phase flow.
Afshin J. Ghajar

Chapter 13. Two-Phase Flow Experimental Setup for Inclined Systems

Abstract
This chapter provides the details of a versatile experimental setup used for flow visualization and collection of pertinent two-phase flow data (void fraction, pressure drop, and non-boiling heat transfer coefficient) in inclined systems.
Afshin J. Ghajar

Chapter 14. Flow Patterns, Flow Pattern Maps, and Flow Pattern Transition Models

Abstract
This chapter provides some of the flow visualization results of the experimental setup discussed in Chap. 13, a succinct review of the flow patterns, flow pattern maps, and flow pattern transition models.
Afshin J. Ghajar

Chapter 15. Void Fraction

Abstract
This chapter first presents parametric analysis of the void fraction and then provides a brief review of some of the modeling techniques for determination of the void fraction and recommendation of well-scrutinized void fraction correlations, followed by an illustrative example.
Afshin J. Ghajar

Chapter 16. Pressure Drop

Abstract
This chapter first presents parametric analysis of the pressure drop and then provides a brief review of the modeling techniques for determination of the pressure drop and recommendation of top-performing pressure drop correlations, followed by an illustrative example.
Afshin J. Ghajar

Chapter 17. Modeling of Stratified Flow

Abstract
This chapter describes step-by-step procedure involved in solving the stratified flow model using three different methods. The three models presented in this chapter are the flat surface model, apparent rough surface model, and the double circle model. An illustrative example demonstrating the use of these three models in determining the void fraction and two-phase frictional pressure drop in stratified flow is also provided.
Afshin J. Ghajar

Chapter 18. Entrainment

Abstract
This chapter briefly presents the entrainment mechanisms and the different correlations used to predict liquid entrainment fraction in gas−liquid annular flow. An illustrative example for calculation of liquid entrainment fraction is also provided.
Afshin J. Ghajar

Chapter 19. Modeling of Annular Flow

Abstract
This chapter presents some salient features of annular flow such as liquid film thickness, liquid film flow rate, interfacial friction, and their interrelationships through the concept of traingular relationship. An illustrative example for calculation of filim thickness, film flow rate, and pressure drop in annular flow using the triangular relationship is also provided.
Afshin J. Ghajar

Chapter 20. Non-boiling Two-Phase Heat Transfer

Abstract
This chapter first presents parametric analysis of the two-phase non-boiling heat transfer coefficient and then provides some recent correlations for prediction of heat transfer coefficient and the application of those correlations to a practical problem.
Afshin J. Ghajar

Backmatter

Weitere Informationen

Premium Partner

    Marktübersichten

    Die im Laufe eines Jahres in der „adhäsion“ veröffentlichten Marktübersichten helfen Anwendern verschiedenster Branchen, sich einen gezielten Überblick über Lieferantenangebote zu verschaffen. 

    Bildnachweise