Macroscopic Streamline Integral Relations for Two-Phase Flows

1975 ◽  
Vol 42 (4) ◽  
pp. 766-770 ◽  
Author(s):  
D. A. Drew

A spout-fluidized bed is an example of a situation where a nonuniform fluid flow through a bed of particles causes particle circulation. Several integral relations are derived from a steady, two-dimensional two-phase flow model. The vorticity of the particle motion enclosed by a particle streamline is shown to be equal to the fluid vorticity enclosed by that streamline. The net flux of fluid vorticity through a particle streamline is shown to be equal to zero. The pressure drop along a fluid streamline is related to the net drag force along that streamline. The net flux of particle vorticity through a fluid streamline is given in terms of the pressure drop. Implications of these relations to the mechanics of particle-fluid flows are discussed. Relations giving the particle vorticity in terms of an integral of the fluid vorticity, and vice versa, are presented. A possible numerical scheme for calculation of the flow fields is discussed.

2007 ◽  
Author(s):  
Wenhong Liu ◽  
Liejin Guo ◽  
Ximin Zhang ◽  
Kai Lin ◽  
Long Yang ◽  
...  

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 510
Author(s):  
Yan Huang ◽  
Bifen Shu ◽  
Shengnan Zhou ◽  
Qi Shi

In this paper, two-phase pressure drop data were obtained for boiling in horizontal rectangular microchannels with a hydraulic diameter of 0.55 mm for R-134a over mass velocities from 790 to 1122, heat fluxes from 0 to 31.08 kW/m2 and vapor qualities from 0 to 0.25. The experimental results show that the Chisholm parameter in the separated flow model relies heavily on the vapor quality, especially in the low vapor quality region (from 0 to 0.1), where the two-phase flow pattern is mainly bubbly and slug flow. Then, the measured pressure drop data are compared with those from six separated flow models. Based on the comparison result, the superficial gas flux is introduced in this paper to consider the comprehensive influence of mass velocity and vapor quality on two-phase flow pressure drop, and a new equation for the Chisholm parameter in the separated flow model is proposed as a function of the superficial gas flux . The mean absolute error (MAE ) of the new flow correlation is 16.82%, which is significantly lower than the other correlations. Moreover, the applicability of the new expression has been verified by the experimental data in other literatures.


2016 ◽  
Vol 94 ◽  
pp. 422-432 ◽  
Author(s):  
N. Chikhi ◽  
R. Clavier ◽  
J.-P. Laurent ◽  
F. Fichot ◽  
M. Quintard

Author(s):  
L. Wenhong ◽  
G. Liejin ◽  
Z. Ximin ◽  
L. Kai ◽  
Y. Long ◽  
...  

2019 ◽  
Vol 112 ◽  
pp. 13-26
Author(s):  
Sonja Weise ◽  
Sebastian Meinicke ◽  
Thomas Wetzel ◽  
Benjamin Dietrich

Author(s):  
I˙smail Teke ◽  
O¨zden Ag˘ra ◽  
Hakan Demir ◽  
S¸. O¨zgu¨r Atayılmaz

In this study, the several well known two-phase viscosity models were used for predicting two-phase flow pressure drop in a smooth tube using Computational Fluid Dynamics (CFD) software at homogenous flow conditions. Pressure drop for two different mass flux values (300 and 650 kg/m2s) for R134a with a saturation temperature of 45 °C in a smooth tube has been modeled according to the homogenous flow model and the results have been compared with the analytical formulas and experimental data from the literature. Three different average viscosity correlations were used. It is seen that the numerical results are in a good agreement with the homogenous flow model and fall in ± 30% band. Also, the results derived from the average viscosity expression are in a good agreement with the results calculated using separated two-phase flow correlations. In addition to this, Artificial Neural Networks (ANNs) were employed for predicting the pressure drop in a horizontal smooth pipe. The trained network gives the best values over the correlations with less than 1% mean relative error.


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