Single-phase fluid flow

A certain amount of information on particle-to-liquid and bed-to-wall heat transfer is available for single-phase fluid flow through a packed bed. It is not clear, however, to what extent this information can be applied to... 

A momentum balance for the flow of a two-phase fluid through a horizontal pipe and an energy balance may be written in an expanded form of that applicable to single-phase fluid flow. These equations for two-phase flow cannot be used in practice since the individual phase velocities and local densities are not known. Some simplification is possible if it... 

A micro-channel heat sink can be classified as single-phase or two-phase according to the state of the coolant inside it. For single-phase fluid flow in smooth... 

Table 3.3 Experimental results of single-phase fluid flow in smooth micro-channels... 

For single-phase fluid flow in smooth micro-channels of hydraulic diameter from 15 to 4,010 pm, in the range of the Reynolds numbers Re < Recr, the Poiseuille number, Po, is independent of the Reynolds number. Re. 

For gas-liquid flows in Regime I, the Lockhart and Martinelli analysis described in Section I,B can be used to calculate the pressure drop, phase holdups, hydraulic diameters, and phase Reynolds numbers. Once these quantities are known, the liquid phase may be treated as a single-phase fluid flowing in an open channel, and the liquid-phase wall heat-transfer coefficient and Peclet number may be calculated in the same manner as in Section lI,B,l,a. The gas-phase Reynolds number is always larger than the liquid-phase Reynolds number, and it is probable that the gas phase is well mixed at any axial position therefore, Pei is assumed to be infinite. The dimensionless group M is easily evaluated from the operating conditions and physical properties. 

Inasmuch as the nature of pipeline elements sets these networks apart from electrical networks (more commonly referred to as electrical circuits) we shall review briefly the modeling of these elements. We shall, however, limit ourselves to the correlations developed for single-phase fluid flow the modeling of two-phase flow is a subject of sufficient diversity and complexity to merit a separate review. 

If the volume change of the gas is neglected, and hence accelerative effects are also neglected, then for single-phase fluid flow. Equation (3) becomes... 

Figure 6.7 Single-phase fluid flow, points E to B.

The pseudo-fluid approach inherits the methodology for analyzing single-phase fluid flow and considers a fluid-particle system to consist of k distinct fictitious fluids with interaction between each other. 

Presented in this section is a very brief overview of the calculation of single-phase fluid flow in pipelines. The reader is referred to one of the many textbooks available on the subject, for example, De Nevers (1970) or Denn (1980). 

Single phase fluid flows (single phase reactors, i.e., laminar and turbulent flows). 

The cross-correlation technique measures the time of flight of an inherent flow tag passing through two sensors separated by a known distance. The technique has been used successfully to monitor single-phase fluid flows in which turbulent eddies modulate the interrogating ultrasonic beams. This type of correlation flowmeter has also been developed for solid/liquid and gas/liquid flows, in which the density fluctuation, caused by clusters of solids and by gas bubbles, is the prime inherent flow tag. 

Single-phase fluid flow in porous media is a well-studied case in the literature. It is important not only for its application, but the characterization of the porous medium itself is also dependent on the study of a single-phase flow. The parameters normally needed are porosity, areal porosity, tortuosity, and permeability. For flow of a constant viscosity Newtonian fluid in a rigid isotropic porous medium, the volume averaged equations can be reduced to the following the continuity equation,... 

Darcy s law was established by Darcy in 1856 (Darcy 1856), which is a standard approach in investigation of single phase fluid flow in microscopically both disordered and homogeneous porous media. The Darcy s law is often written as... 

This condition can be applied for microcondensers and for micro-evaporators where an external two-phase flow sets as constant the wall temperature of the microchannels inside which a single-phase fluid flows. 

The behavior of isothermal pressure-driven single-phase fluid flows in microchannels can be smdied by determining the velocity distribution in the fluid region with the aid of the mass conservation principle continuity equation) and the equations of conservation of fluid momentum [3] ... 

Bucci A, Celata GP, Cumo M, Serra E, Zununo G (2004) Water single-phase fluid flow and heat transfer in capillary tubes. Paper no ICMM2004-2406, second international conference on microchannels and minichannels, Rochester, pp 221-228... 

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