Predictions of Flow-Level Angles in Two-Phase, One-Component Stratified Flow

1971 ◽  
Vol 93 (2) ◽  
pp. 254-255
Author(s):  
P. K. Sarma ◽  
A. S. P. Sarma ◽  
K. Venkata Apparao
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Excellent Agreement ◽  
Analytical Method ◽  
Horizontal Tube ◽  
Stratified Flow ◽  
Two Phase ◽  
Adiabatic Flow ◽  
Flow Phenomena

An analytical method is proposed to predict the flow-level angles under two-phase, one-component stratified flow in a horizontal tube with and without mass transfer. The analysis is restricted to adiabatic flow phenomena. A comparison of the present analysis with the available experimental data has revealed excellent agreement.

The effect of two-phase flow regime on hydrodynamics and mass transfer in a horizontal-tube gas-liquid reactor

1985 ◽  
Vol 50 (3) ◽  
pp. 745-757 ◽  
Author(s):  
Andreas Zahn ◽  
Lothar Ebner ◽  
Kurt Winkler ◽  
Jan Kratochvíl ◽  
Jindřich Zahradník
Keyword(s):  
Mass Transfer ◽  
Pressure Drop ◽  
Flow Regime ◽  
Liquid Flow ◽  
Horizontal Tube ◽  
Liquid Holdup ◽  
Two Phase ◽  
Flow Rates ◽  
Type Relation ◽  
Good Agreement

The effect of two-phase flow regime on decisive hydrodynamic and mass transfer characteristics of horizontal-tube gas-liquid reactors (pressure drop, liquid holdup, kLaL) was determined in a cocurrent-flow experimental unit of the length 4.15 m and diameter 0.05 m with air-water system. An adjustable-height weir was installed in the separation chamber at the reactor outlet to simulate the effect of internal baffles on reactor hydrodynamics. Flow regime maps were developed in the whole range of experimental gas and liquid flow rates both for the weirless arrangement and for the weir height 0.05 m, the former being in good agreement with flow-pattern boundaries presented by Mandhane. In the whole range of experi-mental conditions pressure drop data could be well correlated as a function of gas and liquid flow rates by an empirical exponential-type relation with specific sets of coefficients obtained for individual flow regimes from experimental data. Good agreement was observed between values of pressure drop obtained for weirless arrangement and data calculated from the Lockhart-Martinelli correlation while the contribution of weir to the overall pressure drop was well described by a relation proposed for the pressure loss in closed-end tubes. In the region of negligible weir influence values of liquid holdup were again succesfully correlated by the Lockhart-Martinelli relation while the dependence of liquid holdup data on gas and liquid flow rates obtained under conditions of significant weir effect (i.e. at low flow rates of both phases) could be well described by an empirical exponential-type relation. Results of preliminary kLaL measurements confirmed the decisive effect of the rate of energy dissipation on the intensity of interfacial mass transfer in gas-liquid dispersions.

A Visual and Photographic Study of the Inception of Vaporization in Adiabatic Flow

1964 ◽  
Vol 86 (2) ◽  
pp. 257-261 ◽  
Author(s):  
E. P. Mikol ◽  
J. C. Dudley
Keyword(s):  
Experimental Method ◽  
Two Phase Flow ◽  
Operating Conditions ◽  
Phase Flow ◽  
Two Phase ◽  
Adiabatic Flow ◽  
Index Data ◽  
Flow Phenomena ◽  
Glass Tubes

Data and observations obtained during the study of two-phase flow phenomena for refrigerants flowing in small bore copper and glass tubes have been examined for their significance to the cavitation. Visual and photographic observations have been made of the inception of vaporization and of the movement of the point of inception as operating conditions are varied. Liquid tension has been deduced as occurring in these tests. Liquid tension and cavitation index data are presented. The experimental method is recommended as a means for studying many aspects of the phenomenon of cavitation.

Quantification of the RELAP5 Model Uncertainty for Application to the Loss-of-RHR Event During the Mid-Loop Operation

2009 ◽  
Author(s):  
Ikuo Kinoshita ◽  
Hiroichi Nagumo ◽  
Minoru Yamada ◽  
Yasuhiro Sasaki ◽  
Yoshitaka Yoshida
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Model Uncertainty ◽  
Stratified Flow ◽  
Condensation Heat Transfer ◽  
Analysis Method ◽  
Gas Distribution ◽  
Two Phase ◽  
Model Parameter ◽  
Best Estimate

Best estimate analysis method for the loss of Residual Heat Removal (loss-of-RHR) event during the mid-loop operation is being conducted along the Code Scaling, Applicability and Uncertainty (CSAU) evaluation methodology. The analysis method uses RELAP5/MOD3.2 as a best estimate analysis code. One of the important processes in the CSAU methodology is the development of the Phenomena Identification and Ranking Table (PIRT) which identifies thermal-hydraulic phenomena during the event and ranks the identified phenomena from the view point of influence on the safety evaluation parameters. The safety parameters for evaluation are Reactor Coolant System (RCS) pressure and reactor vessel water level. The PIRT for the reflux cooling of the loss-of-RHR event during the mid-loop operation was developed based on existing integral test results, plant analysis results and related papers considering influence on coolant distribution, non-condensible gas distribution and heat transfer. Referenced integral tests are ROSA-IV/LSTF, BETHSY, PKL and IIST. Uncertainty of RELAP5/MOD3.2 physical models related to high ranked phenomena identified in the PIRT for the reflux cooling is quantified using the related experimental data for application to PWR plant statistical analysis based on the developed verification matrix. Uncertainty quantified models are void model, horizontal stratified flow criteria and SG condensation heat transfer. These models are related to the following phenomena respectively. Void model (interfacial friction factor in bubbly and slug flow regimes): - Two phase expansion in core and upper plenum due to core boiling. - Two phase flow to Steam Generator (SG) inlet plenum and U-tubes. Horizontal stratified flow criterion: - Stratification of flow in hot leg. - Water transportation from hot leg to SG by steam flow. SG condensation heat transfer model: - Heat transfer in SG U-tube under presence of non-condensable gas. Distribution of model parameter multiplier which represents model uncertainty was obtained by either experiment analysis by RELAP5 or comparison of separate RELAP5 model prediction to experimental data. Mean value and standard deviation are calculated for distribution of model parameter multiplier.

Prediction of Gaseous Cavitation Occurrence in Various Liquids Based on Two-Phase Flow Analogy

1981 ◽  
Vol 103 (4) ◽  
pp. 551-556 ◽  
Author(s):  
S. Kamiyama ◽  
T. Yamasaki
Keyword(s):  
Experimental Data ◽  
Analytical Method ◽  
Reasonable Agreement ◽  
Two Phase Flow ◽  
Inert Gas ◽  
Low Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Thermodynamic Effects ◽  
Predicted Values

An analytical method for predicting the cavitation occurrence is developed applying an analogy with the choking condition of two-phase flow. The effects of the presence of inert gas and thermodynamic depression on the inception of cavitation are estimated in various liquids such as water, freon, hydrogen, and sodium. It is clearly shown that the thermodynamic effects are remarkable in the case of low flow velocity in fluids with small Spraker’s B-factor (<1.0m−1). Also, the predicted values show reasonable agreement with some experimental data.

Two Phase Pressure Drops for Refrigerants: A Statistical Comparison Among Experimental Data and Correlations

2006 ◽  
Author(s):  
Adriana Greco ◽  
Rita Mastrullo ◽  
Alfonso W. Mauro ◽  
Giuseppe P. Vanoli
Keyword(s):  
Experimental Data ◽  
Horizontal Tube ◽  
Operating Conditions ◽  
Prediction Methods ◽  
Two Phase Flows ◽  
Two Phase ◽  
Pressure Drops ◽  
Statistical Comparison ◽  
Wide Range ◽  
Phase Pressure

A 962 points database for refrigerants two-phase flows by Greco A. and Vanoli G.P. was statistically compared to four widely used prediction methods by Lockhart and Martinelli, Chawla, Theissing and Mu¨ller-Steinhagen and Heck in order to determine the best one. The experimental points are in a wide range of operating conditions for six pure or mixed refrigerants (R134a, R22, R407C, R507A, R410A and R404A) during evaporation in a smooth horizontal tube of 6 m length and 6 mm ID.

Hydrodynamics and Mass Transfer Simulation in Airlift Bioreactor with Settler using Computational Fluid Dynamics

2017 ◽  
Vol 15 (4) ◽  
Author(s):  
Oscar M. Hernández-Calderón ◽  
Marcos D. González-Llanes ◽  
Erika Y. Rios-Iribe ◽  
Sergio A. Jiménez-Lam ◽  
Ma.del Carmen Chavez-Parga ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Mass Transfer ◽  
Computational Fluid Dynamics ◽  
Liquid Velocity ◽  
Fluid Dynamic ◽  
Gas Holdup ◽  
Airlift Bioreactor ◽  
Cfd Modeling ◽  
Two Phase

Abstract In this work, the effect of inlet-gas superficial velocity over the circulation liquid velocity, gas holdup and mass transfer, from an airlift bioreactor with settler were studied by Computational Fluid Dynamics (CFD) modeling and contrasted with experimental results. Multiphase mixture model and κ-ε turbulence model were used to describe the two phases gas-liquid flow pattern in airlift bioreactor. The hydrodynamic parameters such as liquid circulation velocity and gas holdup were computed by solving the governing equations of continuity, moment and turbulence transport using the finite volume method. Global mass transfer coefficient was evaluated through the Higbie’s penetration theory and the two-phase fluid dynamic theory. Comparison between our numerical data and experimental data previously reported in the literature was done. Numerical and experimental data were very close, and the differences found were discussed in terms of the limitations of this study.

CFD Simulation of Boiling Heat Transfer Using OpenFOAM

2014 ◽  
Author(s):  
Mehrdad Shademan ◽  
Ram Balachandar ◽  
Ron Barron
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Boiling Heat Transfer ◽  
Flow Model ◽  
Cfd Simulation ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Adiabatic Flow ◽  
Heat Transfer Phenomenon

An Eulerian-Eulerian two-phase flow model has been developed to simulate the boiling heat transfer phenomenon in a pipe flow. The model was implemented in the OpenFOAM source code. The code development process was divided into two sections. In the first step, an adiabatic two-phase flow model which takes into account the effect of interfacial forces was developed. In the second step, the energy equation was activated to account for non-adiabatic conditions. In order to include the boiling effect, several different subroutines which model evaporation and condensation phenomena were attached to the solver. Results of the two-phase adiabatic flow and from the boiling model are compared with available numerical and experimental data. The simulation predictions are in reasonable agreement with the experimental data and show significant improvement relative to previous numerical results, which suggests the validity of the developed model for boiling heat transfer problems.

scholarly journals Fluid Flow Phenomena in Dusty Air

1970 ◽  
Vol 92 (3) ◽  
pp. 495-502 ◽  
Author(s):  
M. P. Boyce ◽  
E. F. Blick
Keyword(s):  
Experimental Data ◽  
Skin Friction ◽  
Reynolds Numbers ◽  
Solid Particles ◽  
Pressure Gradients ◽  
Complex Flow ◽  
Two Phase ◽  
Circular Pipes ◽  
Flow Phenomena ◽  
Extensive Experimental Data

The purpose of this study was to obtain extensive experimental data on the effect of skin-friction drag by suspending solid particles in air. The investigation was divided into two parts: The first study consisted of obtaining extensive experimental data on the pressure gradients (which are proportional to skin friction) encountered in circular pipes when a mixture of air with solid particles suspended in it flows through the pipe. The second part deals with the skin friction as measured on a flat plate placed flush with the floor of a wind tunnel having a dusty sub-layer. These studies involved a large range of Reynolds numbers, particle sizes, and weight-flow ratios. A theory is also presented to try and explain some of the complex flow phenomena encountered in a two-phase flow system.

scholarly journals Validation of the heat and mass transfer models within a pressurized water reactor containment using the International Standard Problem No. 47 data

2012 ◽  
Vol 33 (2) ◽  
pp. 23-46 ◽  
Author(s):  
Tomasz Bury ◽  
Jan Składzień ◽  
Adam Fic
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Pressurized Water Reactor ◽  
Two Phase ◽  
Pressurized Water ◽  
Water Reactor ◽  
International Standard ◽  
Standard Problem ◽  
Transfer Models

Abstract A lumped parameter type code, called HEPCAL, has been worked out in the Institute of Thermal Technology of the Silesian University of Technology for simulations of a pressurized water reactor containment transient response to a loss-of-coolant accident. The HEPCAL code has been already verified and validated against available experimental data, which in fact have been taken from separate effect tests mainly. This work is devoted to validation of the latest version of the HEPCAL code against experimental data from more complex tests. These experiments have been performed on three different test rigs (called TOSQAN,MISTRA and ThAI) and a part of them became the basis of the International Standard Problem No. 47 (ISP-47) dedicated to containment thermal-hydraulics. Selected experiments realized within the framework of the ISP-47 project have been simulated using the HEPCAL-AD code. The obtained results allowed for drawing of some important conclusions concerning heat and mass transfer models (especially steam condensation), two-phase flow model and buoyancy effects.

scholarly journals Analytical Evaluation of the Hadron Number in Extensive Air Showers for Rising Inelasticity

1984 ◽  
Vol 39 (12) ◽  
pp. 1172-1174 ◽  
Author(s):  
Jiben Sidhanta ◽  
Rajkumar Roychoudhury
Keyword(s):  
Experimental Data ◽  
Energy Range ◽  
Cross Section ◽  
Excellent Agreement ◽  
Analytical Method ◽  
Numerical Solutions ◽  
High Energy ◽  
Analytical Evaluation ◽  
Air Showers ◽  
Air Shower

A purely analytical method is presented in this paper for evaluating the average number of hadrons (in an air shower) with a given energy as the inelasticity of the cross-section rises. Our result is found to be in excellent agreement with numerical solutions and also with experimental data, particularly in the high energy range.

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