153--Introduction and Fundamentals

doi:10.1615/hedhme.a.000153

Navigation by alphabet

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Taborek, J, xlv-lvi Taitel and Dukler flow regime map, for horizontal and inclined gas- liquid flows, Tamura et al correlation, for surface tension of mixtures, Taylor Forge method, for mechanical design of flanges, comparison with EN13445 method, Taylor series expansion, Teflon, use in heat transfer enhancement: TEMA (Tubular Exchanger Manufacturers Association): Temperature distribution: Tenders for heat exchangers, Terminal free fall velocity, in fluidization, Testing and inspection of heat exchangers: Tetrabromomethane: 1,1,2,2-Tetrachloroethane: Tetrachloroethylene: Tetradecane: Tetradecene: Tetrachlorodifluoroethane (Refrigerant 112): 1,1,1,2-Tetrafluoroethane (Refrigerant R134a): Tetrafluoromethane (Refrigerant 14): Tetrahydrofuran: 1,2,3,4-Tetramethylbenzene: 1,2,3,5-Tetramethylbenzene: 1,2,4,5-Tetramethylbenzene: Thermal conductivity: Thermal contact conductance (TCC), Thermal contact resistance (TCR), Thermal design, constructional features affecting, in shell-and-tube heat exchangers Thermal diffusivity: Thermal expansion coefficient: Thermal leakage in F-type shell-and-tube heat exchangers, Thermal mixing in plate heat exchangers, Thermal stress: Thermocal, heat transfer media, Thermodynamic cycles in refrigeration, Thermodynamic properties: Thermodynamic surface in radiative heat transfer, Thermoexel surface, for enhancement of boiling, Thermofluids, heat transfer medium, Thermosiphon Theta-NTU method: Thickness of boundary layers (displacement, momentum, energy, density, temperature), Thin-wall-type expansion bellows, Thiophene: Thome, J R Three-phase flows: Tie rods in shell-and-tube heat exchangers, Tinker method for shell-side heat transfer in shell-and-tube heat exchangers, Titanium and titanium alloys, T-junctions, loss coefficients in, Tolerances Toluene: m-Toluidine: Tong F-factor method, for critical heat flux with nonuniform heating, Tooth, A S, Total emissivity in gases, Transcendental equations in transient conduction, Transient behavior: Transition boiling: Transition flow, heat transfer in free convective flow over vertical surfaces in, Transitional flow, in combined free and forced convection, Transmission of thermal radiation in solids: Transmissivity of solids: Transport properties: Transverse flow, combined free and forced convection in, Treated surfaces, for augmentation of heat transfer, Triangular duct: Triangular fins, in plate fin exchangers, Triangular relationship, in annular gas-liquid flow, Tribromomethane: 1,1,1-Trichloroethane (Refrigerant 140a): Trichloroethylene: Trichlorofluoromethane (Refrigerant 11) Trichloromethane (Chloroform) (Refrigerant 20): 1,1,2-Trichlorotrifluoroethane (Refrigerant 113): Tridecane: Tridecene: Triethylamine: 1,1,1-Trifluoroethane (Refrigerant 143a): Trifluoromethane (Refrigerant 23): Trimethylamine: 1,2,3-Trimethylbenzene: 1,2,4-Trimethylbenzene: 1,3,5-Trimethylbenzene: 2,2,4-Trimethylpentane (Isooctane): Triphenylmethane: Triple interface (gas/solid/liquid),

Introduction and Fundamentals fouling at,

True temperature difference, in double pipe exchangers, Truelove, J S, Tsotsas, E Tube-baffle damage, in heat exchangers, Tube banks, finned: Tube banks, plain: Tube banks, roughened tubes, effect of roughness on Euler number in, Tube bundles: Tube counts, in shell-and-tube heat exchangers: Tube end attachment, in shell-and-tube heat exchangers, Tube inserts, heat exchangers with, Tube-in-plate extended surface configurations, fin efficiency of, Tube plates, in shell-and-tube heat exchangers: Tube rupture in shell-and-tube heat exchangers, Tube-to-tubesheet attachment, in shell-and-tube heat exchangers, Tubes: Tucker, R J, Tunnel dryer, Turbine exhaust condensers: Turbines, lost work in Turbulence: Turbulent boundary layers: Turbulent buffeting, as source of tube vibration, Turbulent energy, integral equation for, Turbulent flow: Turnarounds, in heat exchangers, Turner, C W, Twisted tapes: Twisted tube heat exchangers, Twisted tubes Two-equation models, for turbulent boundary layers, Two-phase loop with capillary pump, Two-phase flows:

Index

HEDH

A B C D E F G H I J K L M N O P Q R S T

Taborek, J, xlv-lvi Taitel and Dukler flow regime map, for horizontal and inclined gas- liquid flows, Tamura et al correlation, for surface tension of mixtures, Taylor Forge method, for mechanical design of flanges, comparison with EN13445 method, Taylor series expansion, Teflon, use in heat transfer enhancement: TEMA (Tubular Exchanger Manufacturers Association): Temperature distribution: Tenders for heat exchangers, Terminal free fall velocity, in fluidization, Testing and inspection of heat exchangers: Tetrabromomethane: 1,1,2,2-Tetrachloroethane: Tetrachloroethylene: Tetradecane: Tetradecene: Tetrachlorodifluoroethane (Refrigerant 112): 1,1,1,2-Tetrafluoroethane (Refrigerant R134a): Tetrafluoromethane (Refrigerant 14): Tetrahydrofuran: 1,2,3,4-Tetramethylbenzene: 1,2,3,5-Tetramethylbenzene: 1,2,4,5-Tetramethylbenzene: Thermal conductivity: Thermal contact conductance (TCC), Thermal contact resistance (TCR), Thermal design, constructional features affecting, in shell-and-tube heat exchangers Thermal diffusivity: Thermal expansion coefficient: Thermal leakage in F-type shell-and-tube heat exchangers, Thermal mixing in plate heat exchangers, Thermal stress: Thermocal, heat transfer media, Thermodynamic cycles in refrigeration, Thermodynamic properties: Thermodynamic surface in radiative heat transfer, Thermoexel surface, for enhancement of boiling, Thermofluids, heat transfer medium, Thermosiphon Theta-NTU method: Thickness of boundary layers (displacement, momentum, energy, density, temperature), Thin-wall-type expansion bellows, Thiophene: Thome, J R Three-phase flows: Tie rods in shell-and-tube heat exchangers, Tinker method for shell-side heat transfer in shell-and-tube heat exchangers, Titanium and titanium alloys, T-junctions, loss coefficients in, Tolerances Toluene: m-Toluidine: Tong F-factor method, for critical heat flux with nonuniform heating, Tooth, A S, Total emissivity in gases, Transcendental equations in transient conduction, Transient behavior: Transition boiling: Transition flow, heat transfer in free convective flow over vertical surfaces in, Transitional flow, in combined free and forced convection, Transmission of thermal radiation in solids: Transmissivity of solids: Transport properties: Transverse flow, combined free and forced convection in, Treated surfaces, for augmentation of heat transfer, Triangular duct: Triangular fins, in plate fin exchangers, Triangular relationship, in annular gas-liquid flow, Tribromomethane: 1,1,1-Trichloroethane (Refrigerant 140a): Trichloroethylene: Trichlorofluoromethane (Refrigerant 11) Trichloromethane (Chloroform) (Refrigerant 20): 1,1,2-Trichlorotrifluoroethane (Refrigerant 113): Tridecane: Tridecene: Triethylamine: 1,1,1-Trifluoroethane (Refrigerant 143a): Trifluoromethane (Refrigerant 23): Trimethylamine: 1,2,3-Trimethylbenzene: 1,2,4-Trimethylbenzene: 1,3,5-Trimethylbenzene: 2,2,4-Trimethylpentane (Isooctane): Triphenylmethane: Triple interface (gas/solid/liquid),

Introduction and Fundamentals fouling at,

True temperature difference, in double pipe exchangers, Truelove, J S, Tsotsas, E Tube-baffle damage, in heat exchangers, Tube banks, finned: Tube banks, plain: Tube banks, roughened tubes, effect of roughness on Euler number in, Tube bundles: Tube counts, in shell-and-tube heat exchangers: Tube end attachment, in shell-and-tube heat exchangers, Tube inserts, heat exchangers with, Tube-in-plate extended surface configurations, fin efficiency of, Tube plates, in shell-and-tube heat exchangers: Tube rupture in shell-and-tube heat exchangers, Tube-to-tubesheet attachment, in shell-and-tube heat exchangers, Tubes: Tucker, R J, Tunnel dryer, Turbine exhaust condensers: Turbines, lost work in Turbulence: Turbulent boundary layers: Turbulent buffeting, as source of tube vibration, Turbulent energy, integral equation for, Turbulent flow: Turnarounds, in heat exchangers, Turner, C W, Twisted tapes: Twisted tube heat exchangers, Twisted tubes Two-equation models, for turbulent boundary layers, Two-phase loop with capillary pump, Two-phase flows:

U V W X Y Z

Download the citation in the EndNote formatOpen in a new tab. Download the citation in the RefWorks formatOpen in a new tab. Download the citation in the BibTex formatOpen in a new tab.

Introduction and Fundamentals

DOI 10.1615/hedhme.a.000153

2.3.1 Introduction and fundamentals

G. F. Hewitt

A. Classification of multiphase flows

Surveys carried out on industrial heat exchanger systems have indicated that more than half of these involve multiphase flow in one form or another. Multiphase flow’s are ubiquitous in the power generation and process industries and have a very wide range of applications. Such flows are often extremely complex in nature and it should be stated at the outset that many of the relationships used for multiphase flows are of an essentially empirical nature, are of limited applicability, and reflect the poor physical understanding of many two-phase flow phenomena.

This part of the handbook deals with a variety of multiphase flows in which the phases passing through the system may be solid (denoted by the subscript s), liquid (denoted by ℓ ), or gas ¹ (denoted by g ). Some of the characteristic features associated with the behavior of each of these phases in multiphase flows are as follows:

Solids: Normally, the solid phase is in the form of lumps or particles. To all intents and purposes, the solid phase can be regarded as incompressible and to have a nondeformable interface with the fluid phase or phases with which it is flowing. The flow characteristics are strongly dependent on the size of the individual solid elements and on the motions of the associated fluids. Very small particles follow the fluid motions whereas larger particles are less responsive to turbulent eddies in the fluid. Normally, the size is nonuniform and a knowledge of the particle size distribution is of great significance in studying such flows. More often than not, the solid is denser than the associated fluid phases and, in horizontal flow systems, this can give rise to gravitational separation or stratification. Solid particles may adhere to channel walls as permanent fouling layers, and these layers can often be very significant resistances to heat transfer. Examples here would be the deposition of magnetite particles on the tubes of a boiler or deposition of crystalline solids in a cooler crystallizer.
Liquid: In multiphase flows containing a liquid phase, the liquid can be the continuous phase, containing dispersed elements of solids (particles), gases (bubbles), or other liquids (drops). The liquid phase can also be discontinuous, for example, in the form of drops suspended in a gas phase or in another liquid phase. With the exception of some special kinds of non-Newtonian liquids, liquids differ greatly from solids in their response to deforming forces. In solids, provided the force is not too high, a small reversible deformation (elastic) occurs, allowing an equal and opposite force to be transmitted through the solid to balance the imposed force, if the solid is to remain at rest. As a fluid, a liquid does not have this property and a balancing force can only exist if the liquid is in motion. A liquid also differs from a solid insofar as its interface with other fluids (gases or other liquids) is readily deformable. The existence of interfacial tension (which may be regarded as the energy required to form a unit area of interface) tends to limit the deformation. For example, there is a tendency to form spherical droplets when the liquid is the discontinuous phase, such droplets representing the minimum interfacial energy per unit volume of the liquid.
Another important property of liquid phases relates to wetting. When a liquid phase is in contact with a solid phase (such as the channel wall) and is adjacent to another phase which is also in contact with the wall, there exists at the wall a triple interface, and the angle subtended at this interface
Gas: As a fluid, a gas lias the same properties as a liquid in its response to forces. However, it has the important additional property of being (in comparison to liquids and solids) highly compressible. Notwithstanding this property, many multiphase flows containing gases can be treated as essentially incompressible, particularly if the pressure is reasonably high and the Mach number with respect to the gas phase is low (e.g., < 0.2).

Having made some general statements about the properties of the various phases that make up multiphase flows, the common forms of multiphase flow will now be considered and examples given of their applications.

... You need a subscriptionOpen in a new tab. to view the full text of the article. If you already have the subscription, please login here