Correlation of Adiabatic Two-Phase Pressure Drop Data Using the Frictional Law of Corresponding States

1993 ◽  
Vol 115 (2) ◽  
pp. 317-323 ◽  
Author(s):  
N. T. Obot ◽  
M. W. Wambsganss ◽  
D. M. France ◽  
J. A. Jendrzejczyk
Keyword(s):  
Pressure Drop ◽  
Cross Section ◽  
Total Mass ◽  
Single Phase ◽  
Circular Cross Section ◽  
Single Phase Flow ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Law Of Corresponding States ◽  
Total Mass Flux

A method, based on that developed for single-phase flow, is proposed for the correlation of two-phase frictional pressure drop data. It is validated using air-water data obtained on small horizontal passages of rectangular and circular cross-section for values of total mass flux G in the 50-2000 kg/m2s range. The pressure drop for air-water mixtures can be predicted from the proposed correlations provided the critical quality (or superficial gas Reynolds number) and the critical pressure gradient for transition from bubble/plug-to-slug flow are known. A comparison of the proposed method with that of Lockhart and Martinelli is presented and discussed.

Two-Phase Flow Behavior in Channels With Sudden Area Change Using Experimental and Computational Approach

2017 ◽  
Author(s):  
Ashish Kotwal ◽  
Che-Hao Yang ◽  
Clement Tang
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Experimental Analysis ◽  
Single Phase ◽  
Computational Analysis ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Area Change

The current study shows computational and experimental analysis of multiphase flows (gas-liquid two-phase flow) in channels with sudden area change. Four test sections used for sudden contraction and expansion of area in experiments and computational analysis. These are 0.5–0.375, 0.5–0.315, 0.5–0.19, 0.5–0.14, inversely true for expansion channels. Liquid Flow rates ranging from 0.005 kg/s to 0.03 kg/s employed, while gas flow rates ranging from 0.00049 kg/s to 0.029 kg/s implemented. First, single-phase flow consists of only water, and second two-phase Nitrogen-Water mixture flow analyzed experimentally and computationally. For Single-phase flow, two mathematical models used for comparison: the two transport equations k-epsilon turbulence model (K-Epsilon), and the five transport equations Reynolds stress turbulence interaction model (RSM). A Eulerian-Eulerian multiphase approach and the RSM mathematical model developed for two-phase gas-liquid flows based on current experimental data. As area changes, the pressure drop observed, which is directly proportional to the Reynolds number. The computational analysis can show precise prediction and a good agreement with experimental data when area ratio and pressure differences are smaller for laminar and turbulent flows in circular geometries. During two-phase flows, the pressure drop generated shows reasonable dependence on void fraction parameter, regardless of numerical analysis and experimental analysis.

A numerical investigation on single-phase flow characteristics and frictional pressure drop in helical pipes

2020 ◽  
Vol 52 (4) ◽  
pp. 045505
Author(s):  
Pengxin Cheng ◽  
Nan Gui ◽  
Xingtuan Yang ◽  
Jiyuan Tu ◽  
Shengyao Jiang ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Numerical Investigation ◽  
Single Phase ◽  
Flow Characteristics ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Frictional Pressure Drop

Experimental Study and Numerical Analysis of Water Single-Phase Pressure Drop Across an Array of Circular Micro-Pin-Fins

2011 ◽  
Author(s):  
Jonathan R. Mita ◽  
Weilin Qu ◽  
Marcelo H. Kobayashi ◽  
Frank E. Pfefferkorn
Keyword(s):  
Numerical Analysis ◽  
Pressure Drop ◽  
Cross Section ◽  
Single Phase ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Experimental Results ◽  
Inlet Temperature ◽  
Pin Fins ◽  
Micro Pin Fins

This study investigates pressure drop associated with water liquid single-phase flow across an array of staggered micro-pin-fins having circular cross-section. The micro-pin-fins are micro-end milled out of oxygen free copper and have the following dimensions: 180 micron diameter and 683 micron height. The longitudinal pitch and transverse pitch are equal to 400 microns. Seven water inlet temperatures from 22 to 80 °C, and seventeen maximum mass velocities for each inlet temperature, ranging from 159 to 1475 kg/m2s, were tested. The test module was well insulated to maintain adiabatic conditions. The experimental results were compared to those from a micro-pin-fin array having similar size and geometrical arrangement but a square cross-section. The circular micro-pin-fins were seen to yield a significantly lower pressure drop than the square micro-pin-fins. The present experimental results were also compared with the predictions of several friction factor correlations as well as the results from a three-dimensional numerical analysis. Neither was able to accurately predict the experimental data.

Pressure Drop Correlations of Single-Phase and Two-Phase Flow in Rolling Tubes

2006 ◽  
Author(s):  
Xia-Xin Cao ◽  
Chang-Qi Yan ◽  
Pu-Zhen Gao ◽  
Zhong-Ning Sun
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Single Phase ◽  
Experimental Studies ◽  
Frictional Coefficient ◽  
Bubble Flow ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Rolling Condition ◽  
New Correlation

A series of experimental studies of frictional pressure drop for single phase and two-phase bubble flow in smooth rolling tubes were carried out. The tube inside diameters were 15mm, 25mm and 34.5mm respectively, the rolling angles of tubes could be set as 10° and 20°, and the rolling periods could be set as 5s, 10s and 15s. Combining with the analysis of single-phase water motion, it was found that the traditional correlations for calculating single-phase frictional coefficient were not suitable for the rolling condition. Based on the experimental data, a new correlation for calculating single-phase frictional coefficient under rolling condition was presented, and the calculations not only agreed well with the experimental data, but also could display the periodically dynamic characteristics of frictional coefficients. Applying the new correlation to homogeneous flow model, two-phase frictional pressure drop of bubble flow in rolling tubes could be calculated, the results showed that the relative error between calculation and experimental data was less than ± 25%.

Single- and two-phase pressure drop through vertical Venturis

2020 ◽  
Vol 234 (12) ◽  
pp. 2349-2359 ◽  
Author(s):  
Abdelkader Messilem ◽  
Abdelwahid Azzi ◽  
Ammar Zeghloul ◽  
Faiza Saidj ◽  
Hiba Bouyahiaoui ◽  
...  
Keyword(s):  
Pressure Drop ◽  
High Reynolds Number ◽  
Single Phase ◽  
Area Ratio ◽  
Superficial Velocity ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Two Phase ◽  
High Reynolds ◽  
Phase Pressure

An experimental investigation of the pressure drops measurements in a Venturi placed in a vertical pipe is achieved. Venturis with diameter ratios equal to 0.4, 0.55, and 0.75 were employed. Differential pressure transducers were used to measure the pressure drop between the Venturi inlet and the throat sections. The void fraction was measured upstream the Venturi using a conductance probe technique. Air and water superficial velocities ranges were chosen to cover single-phase flow and bubbly, slug, and churn flow regimes. The single-phase pressure drop increases with the liquid superficial velocity. The Venturi pressure drop coefficient increases with decreasing the Venturi area ratio. The discharge coefficient increases slightly with this ratio and approaches a value of unity at high Reynolds number. The two-phase flow pressure drop and the multiplier coefficient increase with the gas superficial velocity and with decreasing the area ratio. Dimensionless pressure drop decreases with increasing the liquid to gas superficial velocity ratio and approaches an asymptotic value at high ratio (greater than 10). This value matches the single-phase flow dimensionless pressure drop value at high Reynolds number. The Venturi with area ratio equal to 0.55 was shown to correlate well the two-phase multiplier and the liquid holdup.

Thermofluid Characteristics of Two-Phase Microgap Coolers

2007 ◽  
Author(s):  
Dae W. Kim ◽  
Emil Rahim ◽  
Avram Bar-Cohen ◽  
Bongtae Han
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Pressure Drop ◽  
Single Phase ◽  
Flow Boiling ◽  
Phase Flow ◽  
Dissolved Gas ◽  
Single Phase Flow ◽  
Two Phase ◽  
Phase Water

The thermofluid characteristics of a chip-scale microgap cooler, including single-phase flow of water and FC-72 and flow boiling of FC-72, are explored. Heat transfer and pressure drop results for single phase water are used to validate a detailed numerical model and, together with the convective FC-72 data, establish a baseline for microgap cooler performance. Experimental results for single phase water and FC-72 flowing in 120 μm, 260 μm and 600 μm microgap coolers, 31mm wide by 34mm long, at velocities of 0.1 – 2 m/s are reported. “Pseudo-boiling” driven by dissolved gas and flow boiling of FC-72 are found to provide significant enhancement in heat transfer relative to theoretical single phase values.

Frictional Pressure Drop Correlations for Single-Phase Flow, Condensation, and Evaporation in Microfin Tubes

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Zan Wu ◽  
Bengt Sundén
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Single Phase ◽  
Flow Boiling ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Frictional Pressure Drop ◽  
Friction Factors ◽  
Flow Condensation ◽  
Microfin Tubes

Experimental single-phase, condensation, and evaporation (flow boiling) pressure drop data from the literature and our previous studies were collected to evaluate previous frictional pressure drop correlations for horizontal microfin tubes of different geometries. The modified Ravigururajan and Bergles correlation, by adopting the Churchill model to calculate the smooth-tube friction factor and by using the hydraulic diameter in the Reynolds number, can predict single-phase turbulent frictional pressure drop data relatively well. Eleven pressure drop correlations were evaluated by the collected database for condensation and evaporation. Correlations originally developed for condensation and evaporation in smooth tubes can be suitable for microfin tubes if the friction factors in the correlations were calculated by the Churchill model to include microfin effects. The three most accurate correlations were recommended for condensation and evaporation in microfin tubes. The Cavallini et al. correlation and the modified Friedel correlation can give good predictions for both condensation and evaporation. However, some inconsistencies were found, even for the recommended correlations.

Pressure Drop for Single- and Two-Phase Flows Through a Return Bend in Horizontal Rectangular Microchannel and Minichannel

2015 ◽  
Author(s):  
Akimaro Kawahara ◽  
Michio Sadatomi ◽  
Shinichi Miyagawa ◽  
Mohamed H. Mansour
Keyword(s):  
Pressure Drop ◽  
Pressure Loss ◽  
Single Phase ◽  
Distribution Data ◽  
Micro Channel ◽  
Two Phase Flows ◽  
Two Phase ◽  
Rectangular Microchannel ◽  
Frictional Pressure Drop ◽  
Mini Channels

In this paper, single-phase liquid and two-phase gas-liquid pressure drop data through 180° return bends have been obtained for horizontal rectangular micro-channel and mini-channel. To investigate the size effects of the test channels, the hydraulic diameters were 0.25 mm and 3 mm respectively as the micro-channel and the mini-channel. The curvature radii of the bends were 0.500 mm and 0.875 mm for the micro-channel, while 6 mm for the mini-channel. To know liquid properties effects, distilled water, surfactant and glycerin aqueous solutions, ethanol and HFE (hydrofluoroether)-7200 were used as the test liquid, while nitrogen gas and air as the test gas. Pressure distributions upstream and downstream tangents of the bend were measured for the single-phase and the two-phase flows. From the pressure distribution data, the bend pressure loss was determined. By analyzing the present data, the bend loss coefficient for single-phase flow in both micro- and mini-channels could be correlated with Dean number. On the other side, the total bend pressure loss for two-phase flows were correlated by using an approach of Padilla et al., in which the total pressure loss is the sum of two pressure drop components, i.e., frictional pressure drop and singular pressure drop. The approach was found to be applicable to the present data for the micro- and the mini-channels if the frictional pressure drop was calculated by Lockhart-Martinelli method with Mishima & Hibiki’s correlation and Kawahara et al.’s correlation and the singular pressure drop was calculated by a newly developed empirical correlation.

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