scholarly journals Identification of boiling flow pattern in narrow rectangular channel based on TFA-CNN combined method

2021 ◽  
pp. 102086
Author(s):  
A. Wenjun Chu ◽  
B. Yang Liu ◽  
C. Liqiang Pan ◽  
D. Hongye Zhu ◽  
E. Xingtuan Yang
Keyword(s):  
Flow Pattern ◽  
Rectangular Channel ◽  
Combined Method ◽  
Boiling Flow

scholarly journals Flow Pattern Map of Flow Boiling in a Rectangular Channel Filled with Porous Media

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2440
Author(s):  
Youngwoo Kim ◽  
Dae Yeon Kim ◽  
Kyung Chun Kim
Keyword(s):  
Porous Media ◽  
Flow Pattern ◽  
Flow Regime ◽  
Annular Flow ◽  
Flow Boiling ◽  
Rectangular Channel ◽  
Flow Patterns ◽  
Flow Pattern Map ◽  
Mist Flow ◽  
Churn Flow

A flow visualization study was carried out for flow boiling in a rectangular channel filled with and without metallic random porous media. Four main flow patterns are observed as intermittent slug-churn flow, churn-annular flow, annular-mist flow, and mist flow regimes. These flow patterns are clearly classified based on the high-speed images of the channel flow. The results of the flow pattern map according to the mass flow rate were presented using saturation temperatures and the materials of porous media as variables. As the saturation temperatures increased, the annular-mist flow regime occupied a larger area than the lower saturation temperatures condition. Therefore, the churn flow regime is narrower, and the slug flow more quickly turns to annular flow with the increasing vapor quality. The pattern map is not significantly affected by the materials of porous media.

PTV Experiments of Subcooled Boiling Flow Through a Rectangular Channel

2008 ◽  
Author(s):  
Carlos E. Estrada-Perez ◽  
Elvis E. Dominguez-Ontiveros ◽  
Hee Seok Ahn ◽  
Noushin Amini ◽  
Yassin A. Hassan
Keyword(s):  
Turbulence Modeling ◽  
Rectangular Channel ◽  
Reynolds Numbers ◽  
Heat Fluxes ◽  
Heated Wall ◽  
Reynolds Stresses ◽  
Subcooled Boiling ◽  
Square Channel ◽  
Boiling Flow ◽  
Visualization Techniques

Experiments were carried out to investigate turbulent sub-cooled boiling flow of Novec-2000 [1] refrigerant through a vertical square channel with one heated wall. Channel dimensions were selected to be similar to those encountered on a Boiling Water Reactor (BWR) channel flow, with an hydraulic diameter of Dh = 8.2mm. Flow visualization techniques such as Particle Tracking Velocimetry (PTV) and Shadowgraphy were used to measure time-average axial and normal velocities, axial and normal turbulence intensities, and Reynolds Stresses. Results are reported for hydraulic Reynolds numbers at channel inlet of 4638, 14513 and 24188 for up to thirteen wall heat fluxes (q″) ranging from 0.0 to 64.0 kW/m2. This work is an attempt to enrich the database already collected on turbulent subcooled boiling flow, with the hope that it will be useful in turbulence modeling efforts.

Numerical Simulation of the Interfacial Growth of the Stratified Wavy Two-Phase Flow in the Horizontal Rectangular Channel

2004 ◽  
Author(s):  
Ken-ichi Ebihara ◽  
Tadashi Watanabe
Keyword(s):  
Numerical Simulation ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Rectangular Channel ◽  
Channel Width ◽  
Phase Flow ◽  
Dimensionless Numbers ◽  
Two Phase ◽  
Flow Pattern Map ◽  
Interfacial Growth

Two-phase flow is one of the important phenomena that are found in nuclear reactors. It is required for the design and the safe operation of nuclear reactors to understand and predict the two-phase flow phenomenon by numerical analyses. This paper describes the numerical simulation of the interfacial growth of the stratified wavy two-phase flow in the horizontal rectangular channel. This flow is the cocurrent flow separated by gravity and a fundamental flow pattern of two-phase flow. The influence of the channel width upon the growth of the interfacial wave was evaluated by carrying out several simulations for the different channel width. The numerical simulation model adopted in this paper is a one-component two-phase fluid model of the lattice Boltzmann method. This model has been developed and utilized for numerical analyses of two-phase flow in recent years because it has the capability of simulating spontaneous phenomena of the interface between phases. The wave growth was observed and the dimensionless numbers that characterize the two-phase flow state were measured during the computations. The relation between the wave growth and the dimensionless numbers, which were obtained as the computational results was compared with that in the flow pattern map proposed on the basis of theoretical consideration by Taitel and Dukler. It was verified in the case of the wide channel width that the simulated relation was in agreement with that in the theoretical flow pattern map. It was shown that the narrower the channel width became, the more mass flow rate of the rare phase the interfacial growth needed and the obtained relation deviated from that in the flow pattern map.

Two-Phase Flow in a Gas Flow Channel of Polymer Electrolyte Fuel Cells

2011 ◽  
Author(s):  
Sung Chan Cho ◽  
Yun Wang
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Water Droplet ◽  
Two Phase Flow ◽  
Rectangular Channel ◽  
Aluminum Surface ◽  
Carbon Paper ◽  
Phase Flow ◽  
Two Phase ◽  
Phase Pressure

Two-phase flow behavior in a mini channel is studied by both experimental and numerical methods. Various surface conditions are considered to capture the fundamental characteristics of water droplet behavior in a PEMFC gas channel. In the considered rectangular channel with 1 mm height, critical velocity for annular flow type is measured as 1∼2 m/s of superficial air velocity. Two-phase flow pattern shows some uncertainty near transition zone with aluminum surface. With carbon paper GDL, two-phase flow pattern is stabilized. Measured two-phase pressure drop data explains the relation between two-phase flow pattern and two-phase pressure drop. Numerical simulation using VOF technique successfully mimicked the development of water droplet and corner flow as well as formation of a slug. It also explains the possibility of random slug formation with aluminum surface and stabilized two-phase flow pattern with carbon paper GDLs.

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