Liquid and Gas-Phase Distributions in a Jet With Phase Change

1988 ◽  
Vol 110 (4a) ◽  
pp. 955-960 ◽  
Author(s):  
Flavio Dobran
Keyword(s):  
Phase Change ◽  
Pressure Distribution ◽  
Total Pressure ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Gas Velocity ◽  
Flow Properties ◽  
Two Phase ◽  
Pipe Length ◽  
Pressure Peak

A two-phase flow high-velocity jet with phase change was studied numerically. The jet is assumed to be created by the two-phase critical flow discharge through a pipe of variable length and attached to a vessel containing the saturated liquid at different stagnation pressures. The jet flow is assumed to be axisymmetric and the modeling of the two-phase flow was accomplished by a nonequilibrium model that accounts for the relative velocity and temperature difference between the phases. The numerical solution of the governing set of balance and conservation equations revealed steep gradients of flow properties in both radial and axial directions. The liquid phase in the jet is shown to remain close to the jet axis, and its velocity increases until it reaches a maximum corresponding to the gas velocity, and thereafter decreases at the same rate as the gas velocity. The effect of decreasing the pipe length is shown to produce a larger disequilibrium in the jet and a double pressure peak in the total pressure distribution. A comparison of the predicted total pressure distribution in the jet with the experimental data of steam–water at different axial locations is demonstrated to be very reasonable.

Binary two-phase flow with phase change in porous media

2001 ◽  
Vol 27 (3) ◽  
pp. 477-526 ◽  
Author(s):  
S. Békri ◽  
O. Vizika ◽  
J.-F. Thovert ◽  
P.M. Adler
Keyword(s):  
Porous Media ◽  
Phase Change ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase

Two-Phase Flow Correlations as Applied to Pumping Well Testing

1994 ◽  
Vol 116 (2) ◽  
pp. 121-128 ◽  
Author(s):  
C. S. Kabir ◽  
A. R. Hasan
Keyword(s):  
Two Phase Flow ◽  
Laboratory Data ◽  
Objective Evaluation ◽  
Well Testing ◽  
Phase Flow ◽  
Two Phase ◽  
Pipe Length ◽  
Annular Geometry ◽  
Test Computation ◽  
Gas Void Fraction

In a pumping-well buildup test, computation of bottom-hole pressure (BHP) and flow rate (BHF) requires the use of a two-phase flow correlation for estimating the gas void-fraction or holdup along the pipe length and shut-in time. Various correlations are available to perform this task. The purpose of this work is to review these two-phase correlations and to provide an objective evaluation. This analysis is necessitated by the fact that considerable differences in BHP and BHF may occur—depending upon the correlation used—in wells with long pumping liquid columns or those that have high gas/liquid ratio production. Consequently, a potential exists for obtaining different reservoir parameters from transient interpretation. Using laboratory data for two-phase flow in annular geometry, relative strengths of these correlations are explored. Our own data and those of others (a total of 114 points) are used in this comparative study. For static liquid columns, the correlations of Hasan-Kabir, Gilbert, and Podio et al. provide acceptable agreement with experimental data, exceptions being the Godbey-Dimon and Schmidt et al. correlations. In contrast, for the moving liquid column scenario, as in a buildup test, the Hasan-Kabir model provides the best agreement with the dataset used in this work. A basis for smoothing the bubbly/slug transition boundary is given for the Hasan-Kabir method, together with a field example.

scholarly journals A Connectivity-Based Modeling Approach for Representing Hysteresis in Macroscopic Two-Phase Flow Properties

2014 ◽  
Vol 63 ◽  
pp. 3456-3463 ◽  
Author(s):  
Abdullah Cihan ◽  
Jens Birkholzer ◽  
Luca Trevisan ◽  
Marco Bianchi ◽  
Quanlin Zhou ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Properties ◽  
Two Phase ◽  
Modeling Approach

Phase Change and Choked Flow Effects on Rotordynamic Coefficients of Cryogenic Annular Seals

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Mohamed Amine Hassini ◽  
Mihai Arghir
Keyword(s):  
Phase Change ◽  
Two Phase Flow ◽  
Excitation Frequency ◽  
Phase Flow ◽  
Two Phase ◽  
Gaseous Oxygen ◽  
Total Enthalpy ◽  
Choked Flow ◽  
Rotordynamic Coefficients ◽  
Annular Seals

The present work deals with the numerical analysis of phase change effects and choked flow on the rotordynamic coefficients of cryogenic annular seals. The analysis is based on the “bulk flow” equations, with the energy equation written for the total enthalpy, and uses an estimation of the speed of sound that is valid for single- or two-phase flow as well. The numerical treatment of choked flow conditions is validated by comparisons with the experimental data of Hendricks (1987, “Straight Cylindrical Seal for High-Performance Turbomachines,” NASA Technical Paper No. 1850) obtained for gaseous nitrogen. The static characteristics and the dynamic coefficients of an annular seal working with liquid or gaseous oxygen are then investigated numerically. The same seal was used in previous analyses performed by Hughes et al. (1978, “Phase Change in Liquid Face Seals,” ASME J. Lubr. Technol., 100, pp. 74–80), Beatty and Hughes (1987, “Turbulent Two-Phase Flow in Annular Seals,” ASLE Trans., 30(1), pp. 11–18), and Arauz and San Andrés (1998, “Analysis of Two Phase Flow in Cryogenic Damper Seals. Part I: Theoretical Model,” ASME J. Tribol., 120, pp. 221–227 and 1998, “Analysis of Two Phase Flow in Cryogenic Damper Seals. Part 2: Model Validation and Predictions,” ASME J. Tribol., 120, pp. 228–233). The flow in the seal is unchoked, and rotordynamic coefficients show variations, with the excitation frequency depending if the flow is all liquid, all gas, or a liquid-gas mixture. Finally, the pressure ratio and length of the previous seal are changed in order to promote flow choking in the exit section. The rotordynamic coefficients calculated in this case show a dependence on the excitation frequency that differ from the unchoked seal.

Modification of Two Phase Flow Properties by Adsorbed Polymers and Gels

1999 ◽  
Author(s):  
Pacelli L.J. Zitha ◽  
Fred J. Vermolen ◽  
Hans Bruining
Keyword(s):  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Properties ◽  
Two Phase ◽  
Adsorbed Polymers

Performance and pressure distribution changes in a centrifugal pump under two-phase flow

1998 ◽  
Vol 212 (3) ◽  
pp. 165-171 ◽  
Author(s):  
E T Pak ◽  
J C Lee
Keyword(s):  
Pressure Gradient ◽  
Pressure Distribution ◽  
Centrifugal Pump ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Positive Pressure ◽  
Phase Flow ◽  
Flow Conditions ◽  
Two Phase ◽  
Pump Performance

Pump performance characteristics change drastically under two-phase flow conditions from those of single-phase flow. This is due to a change in flow characteristics in the impeller. Owing to a positive pressure gradient the air bubble moves more slowly than the water in the impeller channel, but in the suction surface region of the impeller inlet, where a negative pressure gradient prevails, the bubbles move more quickly than the water. Thus, in the space just after this region the distributions of the void fraction obtained are considerably higher and uneven. The change in the pressure distribution owing to air admission is also particularly evident in the inlet region of the impeller. These changes bring about an alteration of the whole flow pattern in the impeller and also cause a drop in pump performance. The Reynolds-averaged Navier-Stokes equations for two-phase flow in a centrifugal pump impeller are solved using a finite volume method to obtain the pressure, velocities and void fraction respectively. Good agreement is achieved when the predicted results are compared with those measured experimentally within the range of bubbly flow conditions.

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