Nonequilibrium Modeling of Two-Phase Critical Flows in Tubes

1987 ◽  
Vol 109 (3) ◽  
pp. 731-738 ◽  
Author(s):  
F. Dobran
Keyword(s):  
Two Phase Flow ◽  
Numerical Procedure ◽  
Phase Flow ◽  
Water Mixture ◽  
Governing Equations ◽  
Two Phase ◽  
One Dimensional ◽  
Variable Diameter ◽  
Variable Step ◽  
Tube Exit

A nonequilibrium two-phase flow model is described for the analysis of critical flows in variable diameter tubes. Modeling of the two-phase flow mixture in the tube is accomplished by utilizing a one-dimensional form of conservation and balance equations of two-phase flow which account for the relative velocity and temperature differences between the phases. Closure of the governing equations was performed with the constitutive equations which account for different flow regimes, and the solution of the nonlinear set of six differential equations was accomplished by a variable step numerical procedure. Computations were carried out for a steam-water mixture with varying degrees of liquid subcooling and stagnation pressures in the vessel upstream of the tube and for different tube lengths. The numerical results are compared with the experimental data involving critical flows with variable liquid subcoolings, stagnation pressures, and tube lengths, and it is shown that the nonequilibrium model predicts well the critical flow rate, pressure distribution along the tube, and the tube exit pressure.

Modelling of Two Phase Fluid Flow in Small Circular and Rectangular Channels

2004 ◽  
Author(s):  
S. U. Onbasioglu
Keyword(s):  
Two Phase Flow ◽  
Computational Procedure ◽  
Phase Flow ◽  
Water Mixture ◽  
Governing Equations ◽  
Dimensionless Numbers ◽  
Two Phase ◽  
Computational Tools ◽  
Rectangular Channels ◽  
Phase Fluid

The two phase flow of air-water mixture in circular and rectangular channels with hydraulic diameters of 100 μm to 1 mm has been modeled via computational tools. Two phase flow patterns obtained from the computed results have been compared to those of the ones reported in literature and a reasonable agreement has been obtained. After the validation of the computational procedure, keeping the dimensionless numbers relevant to the small hydraulic diameters constant, the size of the channel has been changed to understand the transition to the flow regime in which the “conventional” governing equations fail. Gas and liquid superficial velocities range from 0.083 m/s to 70 m/s and from 0.043 m/s to 5.67 m/s, respectively.

A ONE-DIMENSIONAL TWO-PHASE FLOW MODEL AND EXPERIMENTAL VALIDATION FOR A FLASHING VISCOUS LIQUID IN A SPLASH PLATE NOZZLE

2015 ◽  
Vol 25 (9) ◽  
pp. 795-817 ◽  
Author(s):  
Mika P. Jarvinen ◽  
A. E. P. Kankkunen ◽  
R. Virtanen ◽  
P. H. Miikkulainen ◽  
V. P. Heikkila
Keyword(s):  
Viscous Liquid ◽  
Experimental Validation ◽  
Flow Model ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
One Dimensional

scholarly journals Correction to: One-dimensional drift-flux correlations for two-phase flow in medium-size channels

2021 ◽  
Author(s):  
Takashi Hibiki
Keyword(s):  
Open Access ◽  
Two Phase Flow ◽  
Medium Size ◽  
Phase Flow ◽  
Two Phase ◽  
One Dimensional ◽  
Open Access Publication ◽  
Internet Portal ◽  
Creative Commons ◽  
Drift Flux

The article “One-dimensional drift-flux correlations for two-phase flow in medium-size channels” written by Takashi Hibiki, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 17 April 2019 without open access. After publication in Volume 1, Issue 2, page 85–100, the author(s) decided to opt for Open Choice and to make the article an open access publication. Therefore, the copyright of the article has been changed to © The Author(s) 2020 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Random Forces Resulting From Internal Two-Phase Flow on Bends and Tees

2006 ◽  
Author(s):  
E. de Langre ◽  
J. L. Riverin ◽  
M. J. Pettigrew
Keyword(s):  
Two Phase Flow ◽  
Experimental Results ◽  
Time Dependent ◽  
Phase Flow ◽  
Water Mixture ◽  
Dimensionless Form ◽  
Two Phase ◽  
Practical Applications ◽  
Random Forces

The time dependent forces resulting from a two-phase air-water mixture flowing in an elbow and a tee are measured. Their magnitudes as well as their spectral contents are analyzed. Comparison is made with previous experimental results on similar systems. For practical applications a dimensionless form is proposed to relate the characteristics of these forces to the parameters defining the flow and the geometry of the piping.

Pressure losses of two-phase flow in a variable-diameter tube

2012 ◽  
Vol 47 (11-12) ◽  
pp. 717-724
Author(s):  
V. N. Novozhilov ◽  
D. A. Baranov
Keyword(s):  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Pressure Losses ◽  
Variable Diameter

A Physically Based, One-Dimensional Two-Fluid Model for Direct Contact Condensation of Steam Jets Submerged in Subcooled Water

2015 ◽  
Vol 1 (2) ◽  
Author(s):  
David Heinze ◽  
Thomas Schulenberg ◽  
Lars Behnke
Keyword(s):  
Direct Contact ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Interfacial Area ◽  
Phase Flow ◽  
Two Phase ◽  
One Dimensional ◽  
Two Fluid Model ◽  
Contact Condensation ◽  
Two Fluid

A simulation model for the direct contact condensation of steam in subcooled water is presented that allows determination of major parameters of the process, such as the jet penetration length. Entrainment of water by the steam jet is modeled based on the Kelvin–Helmholtz and Rayleigh–Taylor instability theories. Primary atomization due to acceleration of interfacial waves and secondary atomization due to aerodynamic forces account for the initial size of entrained droplets. The resulting steam-water two-phase flow is simulated based on a one-dimensional two-fluid model. An interfacial area transport equation is used to track changes of the interfacial area density due to droplet entrainment and steam condensation. Interfacial heat and mass transfer rates during condensation are calculated using the two-resistance model. The resulting two-phase flow equations constitute a system of ordinary differential equations, which is solved by means of the explicit Runge–Kutta–Fehlberg algorithm. The simulation results are in good qualitative agreement with published experimental data over a wide range of pool temperatures and mass flow rates.

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