scholarly journals Two-Phase Pressure Drop Calculations in Small Diameter Inclined Tubes

2012 ◽  
Vol 1 (3) ◽  
pp. 168 ◽  
Author(s):  
Arun Autee ◽  
S.Srinivasa Rao ◽  
Ravikumar Puli ◽  
Ramakant Shrivastava
Keyword(s):  
Pressure Drop ◽  
Void Fraction ◽  
Water Pressure ◽  
Small Diameter ◽  
Bond Number ◽  
Two Phase ◽  
Circular Tubes ◽  
Frictional Pressure Drop ◽  
Micro Channels ◽  
Phase Pressure

Effect of inclination on two-phase frictional pressure drop was investigated in small diameter circular tubes with inner diameters of 4.0, 6.0, 8.0 and 10.0 mm using air and water. Pressure drop was measured and compared with various existing models commonly used for macro and micro channels such as homogeneous, Lockhart-Martinelli, Chisholm, Friedel, Mishma Hibiki, and Zang Mishma. It was found that existing correlations are inadequate in predicting pressure drop for small diameter inclined tubes. The void fraction is calculated using a general void fraction correlation in two-phase flow for various pipe orientations. Based on analysis of present experimental frictional pressure drop data, a correlation is proposed for predicting Chisholm parameter C in small diameter inclined tubes. There was a significant ordering of pressure drop data with respect to Reynolds number, Webber number and Bond number for each diameter.

Experimental Investigation and Performance Evaluation of Isothermal Frictional Two Phase Pressure Drop Correlations in Vertical Downward Gas-Liquid Two Phase Flow

2012 ◽  
Author(s):  
Swanand M. Bhagwat ◽  
Mehmet Mollamahmutoglu ◽  
Afshin J. Ghajar
Keyword(s):  
Performance Evaluation ◽  
Pressure Drop ◽  
Void Fraction ◽  
Accurate Estimation ◽  
Correct Prediction ◽  
Experimental Measurements ◽  
Fluid Viscosity ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Phase Pressure

The correct prediction of gas-liquid two phase pressure drop is of immense significance for proper sizing of industrial equipment and safety operations involved in chemical, energy and petrochemical applications. The hydrostatic component of the two phase pressure drop is predicted based on the accurate estimation of void fraction. However, there exists a complexity in correct estimation of the frictional component of two phase pressure drop owing to interfacial friction at dynamic gas-liquid interface. The present study is focused on the experimental measurements of gas-liquid two phase frictional pressure drop and the performance evaluation of eleven correlations for its prediction in vertical downward orientation. The experimental determination of two phase frictional pressure drop is carried out for a 0.01252 m I.D. pipe with surface roughness of 0.0000152 m using air-water as the fluid combination. Unlike most of the other studies centered towards annular flow, this experimental study is spanned over different flow patterns and the entire range of the void fraction. In addition to the experimental measurements, the scope of this study also includes the performance analysis of eleven frictional pressure drop correlations available in the literature. These correlations are those based on the separated flow model initially proposed by Lockhart and Martinelli [1].The available frictional pressure drop correlations are compared against the data measured in the present study. Based on the experimental data available in the literature, the influence of the pipe diameter and fluid viscosity on the frictional pressure drop is also analyzed.

Two-Phase Flow Through Square and Circular Microchannels—Effects of Channel Geometry

2004 ◽  
Vol 126 (4) ◽  
pp. 546-552 ◽  
Author(s):  
Peter M.-Y. Chung ◽  
Masahiro Kawaji ◽  
Akimaro Kawahara ◽  
Yuichi Shibata
Keyword(s):  
Pressure Drop ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Flow Characteristics ◽  
Separated Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Channel Geometry ◽  
Frictional Pressure Drop ◽  
Channel Shape

An adiabatic experiment was conducted to investigate the effect of channel geometry on gas-liquid two-phase flow characteristics in horizontal microchannels. A water-nitrogen gas mixture was pumped through a 96 μm square microchannel and the resulting flow pattern, void fraction and frictional pressure drop data were compared with those previously reported by the authors for a 100 μm circular microchannel. The pressure drop data were best estimated using a separated-flow model and the void fraction increased non-linearly with volumetric quality, regardless of the channel shape. However, the flow maps exhibited transition boundaries that were shifted depending on the channel shape.

Frictional Pressure Drop of Gas-Newtonian and Gas-Non Newtonian Slug Flow in Vertical Pipe

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Subrata Kumar Majumder ◽  
Sandip Ghosh ◽  
Gautam Kundu ◽  
Arun Kumar Mitra
Keyword(s):  
Pressure Drop ◽  
Slug Flow ◽  
Amyl Alcohol ◽  
Newtonian Liquid ◽  
Vertical Pipe ◽  
Two Phase ◽  
Vertical Column ◽  
Frictional Pressure Drop ◽  
Liquid Systems ◽  
Phase Pressure

Experimental study on two-phase pressure drop in a vertical pipe with air-Newtonian and non-Newtonian liquid in slug flow regime has been carried out within a range of gas and liquid flowrate of 0.5×10-4 to 1.92×10-4 m-3/s and 1.6×10-4 to 6.7×10-4 m3/s respectively. In the present study air and four types of liquids such as water, amyl alcohol, glycerin (two different concentrations), and CMC (Sodium Carboxymethyl Cellulose) are used. The present data were analyzed by two-phase friction method. To predict the two-phase pressure drop, correlations have been developed with Newtonian and non-Newtonian liquid. A general correlation was also developed to predict the two-phase pressure drop in a vertical column of diameter 0.01905 m and 3.4 m height combining both the Newtonian and non-Newtonian liquid systems.

Experimental Investigation of the Effect of Surface Tension and the Correlation on Void Fraction and Frictional Pressure Drop of an Air-Liquid Two-Phase Flow in a Horizontal Flat Capillary Rectangular Channel

2003 ◽  
Author(s):  
Hideo Ide ◽  
Tohru Fukano
Keyword(s):  
Surface Tension ◽  
Pressure Drop ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Rectangular Channel ◽  
Surfactant Solution ◽  
Phase Flow ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Effect Of Surface

Air-liquid two-phase flow in a horizontal flat capillary rectangular channel has been studied to clarify the effects of concentration of surfactant solution on the flow phenomena, such as flow patterns, pressure drop, void fraction and so on. The concentrations of surfactant solution were 0, 10, 50 and 100 ppm and the surface tension of each solution was reduced to about 34mN/m from that of pure water of about 72mN/m. The dimension of the channel used was 10.0 mm × 1.0 mm. The drag reduction by mixing the surfactant was examined in both the single phase flow and the two-phase flow. The experimental data of two-phase frictional pressure drop and holdup were compared with the respective correlations which were previously proposed by the other researchers and the present authors. Finally, we proposed new correlations of two-phase frictional pressure drop and holdup in which the effect of surface tension and the aspect ratio of cross section of channel were taken into account.

Two-Phase Pressure Drop of CO2 in Mini Tubes and Microchannels

2003 ◽  
Author(s):  
R. Yun ◽  
Y. Kim
Keyword(s):  
Heat Flux ◽  
Pressure Drop ◽  
Mass Flux ◽  
Large Diameter ◽  
Two Phase ◽  
Heating Method ◽  
Pressure Drops ◽  
Direct Heating ◽  
Frictional Pressure Drop ◽  
Phase Pressure

Two-phase pressure drops of CO2 are investigated in mini tubes with inner diameters of 2.0 and 0.98 mm and in microchannels with hydraulic diameters from 1.08 to 1.54 mm. For the mini tubes, the tests were conducted with a variation of mass flux from 500 to 3570 kg/m2s, heat flux from 7 to 48 kW/m2, while maintaining saturation temperatures at 0°C, 5°C and 10°C. For the microchannels, mass flux was varied from 100 to 400 kg/m2s, and heat flux was altered from 5 to 20 kW/m2. A direct heating method was used to provide heat into the refrigerants. The pressure drop of CO2 in mini tubes shows very similar trends with that in large diameter tubes. Although the microchannel has a small hydraulic diameter, two-phase effects on frictional pressure drop are significant. The Chisholm parameter of the Lockhart and Martinelli correlation is modified by considering diameter effects on the two-phase frictional multiplier.

Generalized Two-Phase Pressure Drop and Heat Transfer Correlations in Evaporative Micro/Mini-Channels

2007 ◽  
Author(s):  
Hee Joon Lee ◽  
Dongyao Liu ◽  
Shi-Chune Yao ◽  
Y. Alyousef
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Bond Number ◽  
Micro Channel ◽  
Two Phase ◽  
Working Fluids ◽  
Operational Conditions ◽  
Micro Channels ◽  
Wide Range ◽  
Existing Data

Existing data base and correlations in literature on the micro-channel pressure drop and heat transfer are reviewed. None of the existing correlations can cover the wide range of working fluids, operational conditions and different microchannel dimensions. The importance of the Bond number, which relates the nominal bubble dimension or capillary parameter with the channel size, is revealed. Using the Bond number, improved correlations of pressure drop and heat transfer are established. The new correlations predict the existing data well over wide ranges of working fluids, operational conditions and dimensions of micro-channels. Furthermore, Bond number could be used as a criterion to classify a flow path as a micro-channel or conventional macro-channel.

Pressure Drop and Void Fraction in Steam-Water Two-Phase Flow at High Pressure

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Wei Liu ◽  
Hidesada Tamai ◽  
Kazuyuki Takase
Keyword(s):  
High Pressure ◽  
Pressure Drop ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Water Pressure ◽  
Homogeneous Model ◽  
Test Fluid ◽  
Phase Flow ◽  
Two Phase ◽  
Drift Flux Model

For a steam generator (SG) in a commercialized sodium-cooled fast breeder reactor (FBR), flow instability in the water side is one of the most important items needing research. As the first step of this research, thermal-hydraulic experiments using water as the test fluid were performed under high pressure conditions at the Japan Atomic Energy Agency (JAEA) by using a circular tube. Void fraction, pressure drop, and heat transfer coefficient data were obtained under 15, 17, and 18 MPa. This paper discusses the steam-water pressure drop and void fraction. Using the obtained data, we evaluated existing correlations for void fraction and two-phase flow multipliers under high pressure. As a result, the drift flux model implemented in the TRAC-BF1 code was confirmed to suitably predict the void fraction well under the present high pressure conditions. For the two-phase flow multiplier, the Chisholm correlation and the homogeneous model were confirmed to be the best under the present high-pressure conditions.

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