Some aspects of testing of two-phase models in the RELAP-5/2 code

1991 ◽  
Vol 71 (3) ◽  
pp. 769-772
Author(s):  
M. I. Marinov ◽  
B. D. Dimitrov ◽  
E. L. Popov
Keyword(s):  
Two Phase ◽  
Phase Models

Two-phase and single phase models of flow of nanofluid in a square cavity: Comparison with experimental results

2016 ◽  
Vol 100 ◽  
pp. 372-380 ◽  
Author(s):  
M. Ziad Saghir ◽  
Amirhossein Ahadi ◽  
Tooraj Yousefi ◽  
Bahram Farahbakhsh
Keyword(s):  
Single Phase ◽  
Experimental Results ◽  
Square Cavity ◽  
Two Phase ◽  
Phase Models

Investigation of transfer line cool-down transients using equilibrium two-phase models

2021 ◽  
Vol 46 (1) ◽  
pp. 96-101
Author(s):  
Keerthi Raj Kunniyoor ◽  
Rahul Govind ◽  
K. S. Venkateswaran ◽  
Parthasarathi Ghosh
Keyword(s):  
Two Phase ◽  
Transfer Line ◽  
Phase Models

Two-phase driver education models applied in Finland and in Austria – Do we have evidence to support the two phase models?

2010 ◽  
Vol 13 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Sami Mynttinen ◽  
Michael Gatscha ◽  
Marita Koivukoski ◽  
Kari Hakuli ◽  
Esko Keskinen
Keyword(s):  
Driver Education ◽  
Two Phase ◽  
Phase Models

Parametric Analysis of Single-Phase and Two-Phase Models of a Microfluidic Direct Methanol Fuel Cell

2013 ◽  
Author(s):  
Usama Tohid ◽  
Arturo Pacheco-Vega
Keyword(s):  
Fuel Cell ◽  
Parametric Analysis ◽  
Single Phase ◽  
Operating Conditions ◽  
Cell Performance ◽  
Geometrical Parameters ◽  
Two Phase ◽  
Flow Rates ◽  
Direct Methanol ◽  
Phase Models

We perform numerical simulations of single-phase and two-phase models of a direct methanol microfluidic fuel cell (μ-DMFC). The focus of this study is on the parametric analysis of a single channel of the system, for specific sets of operating conditions, in order to map the dependence of the cell performance with respect to the geometrical parameters. Different geometries, ranging from 500 μm to 4 mm in width, and 500 μm to 4 cm in length, along with membrane thicknesses from 50 μm to 500 μm, were considered. The mathematical models are given in terms of the Navier-Stokes, the Butler-Volmer and the Maxwell-Stefan equations, along with Darcy’s equation for the flow across the membrane. The difference between the single- and two-phase flow models lies upon the specific constitutive equations used. For each geometry and operating condition, the two-dimensional equations were solved by a finite element method. The conditions of operation include: flow rates and inlet weight fractions of methanol at the anode and oxygen the cathode. The results from this analysis, presented as polarization curves and power densities, indicate that fuel-cell systems with higher flow rates and inlet weight fraction of methanol achieve the best performance. However, when the concentration of methanol exceeds 2M the cell performance is negatively impacted due to crossover. Comparison of the results indicates that the two-phase model has a more restrictive domain for both the geometrical parameters and operating conditions.

Assessment of Single and Two-Phase Models for Nanofluid Flow at the Entrance Region of a Uniformly Heated Tube

2012 ◽  
Author(s):  
Sinan Goktepe ◽  
Kunt Atalik ◽  
Hakan Erturk
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Friction Factor ◽  
Convective Heat ◽  
Control Volume ◽  
Convective Heat Transfer Coefficient ◽  
Computational Cost ◽  
Nanofluid Flow ◽  
Two Phase ◽  
Phase Models

Hydrodynamic and thermal characteristics of Al2O3 – water nanofluid flow at entry region of a uniformly heated pipe are studied applying finite control volume method (FCV). Single phase and Eulerian-Eulerian two-phase models were used in modelling of nanofluid flow and heat transfer. The two methods are evaluated by comparing predicted convective heat transfer coefficients and friction factor with experimental results from literature. Solutions with two different velocity pressure coupling algorithms, Full Multiphase Coupled, and Phase Coupled Semi-Implicit Method for Pressure Linked Equations are also compared in terms of accuracy and computational cost. Two-phase model predicts convective heat transfer coefficient and friction factor more accurately at the entry region. Moreover, computational cost can be reduced by implementing Full Multiphase Coupled scheme.

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