Modelling of local two-phase flow parameters in upward subcooled flow boiling at low pressure

2004 ◽  
Vol 47 (6-7) ◽  
pp. 1499-1513 ◽  
Author(s):  
Boštjan Končar ◽  
Ivo Kljenak ◽  
Borut Mavko
Keyword(s):  
Two Phase Flow ◽  
Flow Boiling ◽  
Low Pressure ◽  
Phase Flow ◽  
Two Phase ◽  
Subcooled Flow Boiling ◽  
Flow Parameters ◽  
Subcooled Flow

Flow Boiling in Horizontal Tubes: Part 1—Development of a Diabatic Two-Phase Flow Pattern Map

1998 ◽  
Vol 120 (1) ◽  
pp. 140-147 ◽  
Author(s):  
N. Kattan ◽  
J. R. Thome ◽  
D. Favrat
Keyword(s):  
Flow Pattern ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Parameters ◽  
Horizontal Tubes ◽  
Flow Pattern Map ◽  
Wide Range ◽  
Data Points

An improved two-phase flow pattern map is proposed for evaporation in horizontal tubes. The new map was developed based on flow pattern data for five different refrigerants covering a wide range of mass velocities and vapor qualities. The new map is valid for both adiabatic and diabatic (evaporating) flows and accurately identifies about 96 percent of the 702 data points. In addition, the new flow pattern map includes the prediction of the onset of dryout at the top of the tube during evaporation inside horizontal tubes as a function of heat flux and flow parameters.

Pressure Drop Characteristics of Flow Boiling in Narrow Rectangular Channel

2013 ◽  
Author(s):  
Shu-ping Lv ◽  
Liang-ming Pan ◽  
De-qi Chen
Keyword(s):  
Pressure Drop ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Rectangular Channel ◽  
Working Fluid ◽  
Phase Flow ◽  
Two Phase ◽  
Experimental Conditions ◽  
Subcooled Flow Boiling ◽  
Flow Pressure

Pressure drop is the earliest and the most extensive issue in the research of two phase flow. Due to the influence of various factors on two phase flow pressure drop, there is no accurate and general correlation on this issue yet. In this paper, pressure drop characteristics of flow boiling were studied in a single vertical narrow rectangular channel with cross-section of 47 mm by 1.8 mm using water as working fluid. Subcooled flow boiling was experimentally investigated. The experimental conditions included inlet subcooling (2°C∼18°C), mass flow rate (222.3∼457.4 kg.m2s−1) and heat flux (113.6∼270.5 kW/m2). The influence of these parameters on the characteristics of flow boiling pressure drop has been investigated. The experimental results show that the conventional correlations failed to predict the two-phase flow pressure drop in this narrow rectangular channel. According to experiment results, a modified Chisholm correlation was proposed, and the new correlation gave more accurate predictions of the pressure drop.

Enhancing Numerical Stability of a Two-Fluid Model by the Use of Interfacial Pressure Terms

2015 ◽  
Vol 1 (2) ◽  
Author(s):  
Tomio Okawa
Keyword(s):  
Numerical Stability ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Fluid Model ◽  
Phase Flow ◽  
Two Phase ◽  
Subcooled Flow Boiling ◽  
Interfacial Pressure ◽  
Two Fluid Model ◽  
Two Fluid

Analytical and numerical investigations were carried out to show that the characteristics and the numerical stability of the two-fluid model are improved by the use of the interfacial pressure terms that express the pressure difference between bubbles and continuous liquid phase in bubbly two-phase flow. In particular, it was demonstrated that the numerical stability is enhanced not only in the simulation of adiabatic two-phase flow but also in the simulation of subcooled flow boiling.

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