Review—Theoretical Models of Gas-Liquid Flows

1982 ◽  
Vol 104 (3) ◽  
pp. 279-283 ◽  
Author(s):  
G. B. Wallis
Keyword(s):  
Theoretical Model ◽  
Ad Hoc ◽  
Two Phase Flow ◽  
Theoretical Models ◽  
Phase Flow ◽  
Two Phase ◽  
Methods Of Analysis ◽  
Liquid Flows ◽  
Two Fluid

Two-phase flow is an “insecure” science. Many factors influence the phenomena, limiting the value of theory unless supported and guided by observation. Several methods of analysis are available; they should be used carefully and often need to be adapted in an “ad hoc” way to solve particular problems. Current efforts are concentrated on the separated (two-fluid) theoretical model and the development of improved instrumentation.

Modeling of Sodium Two-Phase Flow With the TRACE Code

2009 ◽  
Author(s):  
Aurelia Chenu ◽  
Konstantin Mikityuk ◽  
Rakesh Chawla
Keyword(s):  
Single Phase ◽  
Two Phase Flow ◽  
Flow Simulation ◽  
Phase Flow ◽  
Fluid Models ◽  
Code System ◽  
Two Phase ◽  
Liquid Flows ◽  
Transfer Mechanisms ◽  
Two Fluid

In the framework of PSI’s FAST code system, the TRACE thermal-hydraulics code is being extended for representation of sodium two-phase flow. As the currently available version (v.5) is limited to the simulation of only single-phase sodium flow, its applicability range is not enough to study the behavior of a Sodium-cooled Fast Reactor (SFR) during a transient in which boiling is anticipated. The work reported here concerns the extension of the two-fluid models, which are available in TRACE for steam-water, to sodium two-phase flow simulation. The conventional correlations for ordinary gas-liquid flows are used as basis, with optional correlations specific to liquid metal when necessary. A number of new models for representation of the constitutive equations specific to sodium, with a particular emphasis on the interfacial transfer mechanisms, have been implemented and compared with the original closure models. As a first application, the extended TRACE code has been used to model experiments that simulate a loss-of-flow (LOF) accident in a SFR. The comparison of the computed results, with both the experimental data and SIMMER-III code predictions, has enabled validation of the capability of the modified TRACE code to predict sodium boiling onset, flow regimes, dryout, flow reversal, etc. The performed study is a first-of-a-kind application of the TRACE code to two-phase sodium flow. Other integral experiments are planned to be simulated to further develop and validate the two-phase sodium flow methodology.

scholarly journals Natural modes of the two-fluid model of two-phase flow

2021 ◽  
Vol 33 (3) ◽  
pp. 033324
Author(s):  
Alejandro Clausse ◽  
Martín López de Bertodano
Keyword(s):  
Two Phase Flow ◽  
Fluid Model ◽  
Phase Flow ◽  
Two Phase ◽  
Natural Modes ◽  
Two Fluid Model ◽  
Two Fluid

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.

Gas-Liquid Two-Phase Flow Detection Techniques Based on Internal and External Tube Differential Pressure Flowmeter

2014 ◽  
Vol 568-570 ◽  
pp. 363-369
Author(s):  
Li Li Pang ◽  
Han Chuan Dong ◽  
Yun Shi ◽  
Li De Fang
Keyword(s):  
Cfd Simulation ◽  
Two Phase Flow ◽  
Theoretical Models ◽  
Differential Pressure ◽  
Phase Flow ◽  
Two Phase ◽  
Modified Model ◽  
Detection Techniques ◽  
External Tube ◽  
Flow Detection

The gas-liquid two-phase flow exists widely in nature and in our daily life, to realize the phase flow does not separate online measurement has become an important subject in the study. Through CFD simulation experiment, the optimal structure of inner and outer tube differential pressure flowmeter prototype. Through the analysis of the experimental data, comparison of the classical theoretical models found high Chishlom prediction model error is minimum. Moisture the modified model, the relative error of measurement is better than in the range of experiment 5%.

An Evaluation of Existing Two-Phase Flow Correlations for Use With ASME Sharp Edge Metering Orifices

1977 ◽  
Vol 99 (3) ◽  
pp. 343-347 ◽  
Author(s):  
L. T. Smith ◽  
J. W. Murdock ◽  
R. S. Applebaum
Keyword(s):  
Natural Gas ◽  
Data Base ◽  
Root Mean Square ◽  
Two Phase Flow ◽  
Salt Water ◽  
Sharp Edge ◽  
Phase Flow ◽  
Mean Square ◽  
Two Phase ◽  
Liquid Flows

The two-phase flow correlations developed by Murdock, James, Marriott, and Smith and Leang are evaluated for the case of flow through sharp edge measuring orifices which physically meet ASME standards for flow measurement. The evaluation is based on two sets of consistent orifice flow data. The first data base consists of 34 test points for the flow of steam-water mixtures. The second data base consists of 81 data points for the flow of air-water, natural gas-water, natural gas-salt water, and natural gas-distillate mixtures. The root mean square fractional deviation of each correlation is used to determine its predictive reliability. Computed root mean square fraction deviations for steam-water flows are: James, ±0.081; Marriott, ±0.114; Murdock, ±0.141; Smith and Leang, ±0.218. For the case of gas-liquid flows, the values are: Murdock, ±0.074; James, ±0.178; Smith and Leang, ±0.183; Marriott, ±0.458.

Two-Phase Flow in Liquid Filled Vessels During the Depressurization by Periodic Venting

2003 ◽  
Author(s):  
Dieter Mewes ◽  
Dirk Schmitz
Keyword(s):  
Single Phase ◽  
Two Phase Flow ◽  
Bubbly Flow ◽  
Exothermic Reaction ◽  
Liquid Mixtures ◽  
Phase Flow ◽  
Two Phase ◽  
Pressure Losses ◽  
Short Period ◽  
Liquid Flows

Pressurized chemical reactors or storage vessels are often partly filled with liquid mixtures of reacting components. In case of an unexpected and uncontrolled exothermic reaction the temperature might increase. By this the pressure follows and would exceed a critical maximum value if there would be no mechanism to decrease the pressure and the temperature in a very short period of time. A sudden venting by the opening of a safety valve or a rupture disc causes a rapid vaporization of the reacting liquid mixture. A two-phase flow will pass the ventline. Since two-phase gas-liquid flows cause high pressure losses and give rise to limited mass flows leaving the reactor, single-phase gas flows are preferred. This is emphasized by a periodic venting mechanism of the pressurized vessel. Each time the two-phase flow from the bubbling-up liquid inside the vessel reaches a certain cross-section close the entrance of the ventline. The outlet-valve is closed. Inside the vessel the increasing pressure stops the two-phase flow and only single phase flow is leaving the vessel. The two-phase bubbly flow inside the vessel is detected by a tomographic measurement device during the venting process. Experimental results for local and time dependant phase void fractions as well as pressures are compared with those obtained by numerical calculations of the instationary bubble swarm behavior inside the vessel.

Two-fluid equation for two-phase flow considering change in volume porosity

2019 ◽  
Vol 347 ◽  
pp. 1-9
Author(s):  
Jong Hyuk Lee ◽  
Byoung Jae Kim ◽  
Seung Wook Lee ◽  
Kyung Doo Kim
Keyword(s):  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Fluid Equation ◽  
Volume Porosity ◽  
Two Fluid
Sign in / Sign up

Export Citation Format

Share Document