An investigation of two-phase flow pressure drop in helical rectangular channel

2014 ◽  
Vol 54 ◽  
pp. 33-41 ◽  
Author(s):  
Guo-dong Xia ◽  
Xian-fei Liu
Keyword(s):  
Pressure Drop ◽  
Two Phase Flow ◽  
Rectangular Channel ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Pressure

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.

Evaluation Analysis of Prediction Methods for Two-Phase Flow Pressure Drop in Mini-Channels

2008 ◽  
Author(s):  
Licheng Sun ◽  
Kaichiro Mishima
Keyword(s):  
Pressure Drop ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Turbulent Region ◽  
Frictional Pressure Drop ◽  
New Correlation ◽  
Mini Channels ◽  
Flow Pressure ◽  
Better Than

2092 data of two-phase flow pressure drop were collected from 18 published papers of which the working fluids include R123, R134a, R22, R236ea, R245fa, R404a, R407C, R410a, R507, CO2, water and air. The hydraulic diameter ranges from 0.506 to 12mm; Relo from 10 to 37000, and Rego from 3 to 4×105. 11 correlations and models for calculating the two-phase frictional pressure drop were evaluated based upon these data. The results show that the accuracy of the Lockhart-Martinelli method, Mishima and Hibiki correlation, Zhang and Mishima correlation and Lee and Mudawar correalion in the laminar region is very close to each other, while the Muller-Steinhagen and Heck correlation is the best among the evaluated correlations in the turbulent region. A modified Chisholm correlation was proposed, which is better than all of the evaluated correlations in the turbulent region and its mean relative error is about 29%. For refrigerants only, the new correlation and Muller-Steinhagen and Heck correlation are very close to each other and give better agreement than the other evaluated correlations.

New Correlation for Two-Phase Flow in 90 Degree Horizontal Elbows

2010 ◽  
Author(s):  
Florencio Sanchez-Silva ◽  
Ignacio Carvajal-Mariscal ◽  
Rene Tolentino-Eslava
Keyword(s):  
Pressure Drop ◽  
Two Phase Flow ◽  
Experimental Results ◽  
Galvanized Steel ◽  
Average Error ◽  
Phase Flow ◽  
Volumetric Fraction ◽  
Dean Number ◽  
Two Phase ◽  
Flow Pressure

The comparison of experimental data and results obtained from four global models — homogeneous, Dukler, Martinelli and Chisholm, used to evaluate the two-phase flow pressure drop in circular 90° horizontal elbows — is presented in this paper. An experimental investigation was carried out using three galvanized steel 90° horizontal elbows (E1, E2, E3) with internal diameters of 26.5, 41.2 and 52.5 mm, and curvature radii of 194.0, 264.0 and 326.6 mm, respectively. According to the experimental results, the model proposed by Chisholm best fitted them, presenting for each elbow an average error of E1 = 18.27%, E2 = 28.40% and E3 = 42.10%. Based on experimental results two correlations were developed. The first one is the classical Chisholm model modified to obtain better results in a wider range of conditions; it was adjusted by a dimensionless relationship which is a function of the homogeneous volumetric fraction and the Dean number. As a result, the predictions using modified Chisholm model were improved presenting an average error of 8.66%. The second developed correlation is based on the entire two-phase mass flow taken as liquid and adjusted by the homogeneous volumetric fraction ratio. The results show that this last correlation is easier and accurate than the adjusted Chisholm model, presenting an average error of 7.75%. Therefore, this correlation is recommended for two-phase pressure drop evaluation in horizontal elbows.

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