Experimental Study of Water Liquid-Vapor Two-Phase Pressure Drop Across an Array of Staggered Micropin-Fins

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Christopher A. Konishi ◽  
Weilin Qu ◽  
Frank E. Pfefferkorn
Keyword(s):  
Pressure Drop ◽  
Equivalent Diameter ◽  
Maximum Mass ◽  
Two Phase ◽  
Pin Fin ◽  
Friction Factor Correlation ◽  
Measured Pressure ◽  
Test Module ◽  
Phase Pressure ◽  
Liquid Vapor

This study concerns pressure drop of adiabatic water liquid-vapor two-phase flow across an array of 1950 staggered square micropin-fins having a 200×200 μm cross section by 670 μm height. The ratios of longitudinal pitch and transverse pitch to pin-fin equivalent diameter are equal to 2. An inline immersion heater upstream of the micropin-fin test module was employed to produce liquid-vapor two-phase mixture, which flowed across the micropin-fin array. The test module was well insulated to maintain adiabatic condition. Four maximum mass velocities of 184 kg/m2 s, 235 kg/m2 s, 337 kg/m2 s, and 391 kg/m2 s, and a range of vapor qualities for each maximum mass velocity were tested. Measured pressure drop increases drastically with increasing vapor quality. Nine existing two-phase pressure drop models and correlations were assessed. The Lockhart–Martinelli correlation for laminar liquid-laminar vapor combination in conjunction with a single-phase friction factor correlation proposed for the present micropin-fin array provided the best agreement with the data.

Experimental Study of Adiabatic Water Liquid-Vapor Two-Phase Pressure Drop Across an Array of Staggered Micro-Pin-Fins

2008 ◽  
Author(s):  
Christopher A. Konishi ◽  
Weilin Qu ◽  
Ben Jasperson ◽  
Frank E. Pfefferkorn ◽  
Kevin T. Turner
Keyword(s):  
Pressure Drop ◽  
Maximum Mass ◽  
Two Phase ◽  
Pin Fin ◽  
Pin Fins ◽  
Micro Pin Fins ◽  
Pin Fin Array ◽  
Test Module ◽  
Phase Pressure ◽  
Liquid Vapor

This study concerns pressure drop of adiabatic water liquid-vapor two-phase flow across an array of 1950 staggered square micro-pin-fins having a 200×200 micron cross-section by a 670 micron height. The ratios of longitudinal pitch and transverse pitch to pin-fin equivalent diameter are equal to 2. An inline immersion heater upstream of the micro-pin-fin test module was employed to produce liquid-vapor two-phase mixture, which flowed across the micro-pin-fin array. The test module was well insulated to maintain an adiabatic condition. Four maximum mass velocities of 184, 235, 337, and 391 kg/m2s, and a range of vapor qualities for each maximum mass velocity were tested. Measured pressure drop increases drastically with increasing vapor quality. Nine existing two-phase pressure drop models and correlations were assessed. The Lockhart-Martinelli correlation for laminar liquid-laminar vapor combination in conjunction with a single-phase friction factor correlation proposed for the present micro-pin-fin array provided the best agreement with the data.

Two-Phase Pressure Drop Prediction in Wet Gas Flow Through V-Cone Meter

2014 ◽  
Author(s):  
Denghui He ◽  
Bofeng Bai
Keyword(s):  
Pressure Drop ◽  
Relative Error ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Flow ◽  
Equivalent Diameter ◽  
Operating Pressure ◽  
Two Phase ◽  
Wet Gas ◽  
Phase Pressure

The pressure drop is considerably significant for the differential pressure meter to measure the flow rate of the two-phase flow. Little is known about the pressure drop characteristics of the V-Cone meter when it is used to measure the wet gas flow. The objective of this paper is to investigate the two-phase pressure drop of the V-Cone meter and develop a correlation for predicting its pressure drop. A V-Cone meter with the equivalent diameter ratio of 0.55 was investigated experimentally. The experimental fluid was air and water. The test pressure ranged from 0.1 MPa to 0.4 MPa, and the gas and liquid mass flow rate ranged from 100 Nm3/h to 500 Nm3/h and from 0.05 m3/h to 2.2 m3/h, respectively. The experimental results showed that the existing correlations, which are developed for the orifice plate meter and the Venturi meter, are not applicable for the V-Cone meter to predict the pressure drop. The two-phase mass flow coefficient, K, was used to develop the two-phase pressure drop correlation. The influences of the Lockhart-Martinelli parameter, the gas densiometric Froude number and the operating pressure on K were investigated. The new pressure drop correlation can accurately predict the pressure drop of the V-Cone meter for the wet gas. The relative error of the pressure drop is less than ± 9.0% at the 95.1% confidence level and the average relative error is 3.88%. The pressure drop prediction correlation provides a reference for developing the correlation of the wet gas measurement.

Two-Phase Pressure Drop in the Intermittent Flow Regime for Noncircular Microchannels

2002 ◽  
Author(s):  
Srinivas Garimella ◽  
Jesse D. Killion ◽  
John W. Coleman
Keyword(s):  
Pressure Drop ◽  
Flow Regime ◽  
Intermittent Flow ◽  
Average Error ◽  
Two Phase ◽  
Pressure Drops ◽  
Mass Fluxes ◽  
Tube Shape ◽  
Measured Pressure ◽  
Phase Pressure

This paper reports the development of an experimentally validated model for pressure drop during intermittent flow of condensing refrigerant R134a in horizontal, noncircular microchannels. Two-phase pressure drops were measured in six noncircular channels ranging in hydraulic diameter from 0.42 mm to 0.84 mm. The tube shapes included square, rectangular, triangular, barrel-shaped, and others. For each tube under consideration, pressure drop measurements were taken over the entire range of qualities from vapor to liquid at five different refrigerant mass fluxes between 150 kg/m2s and 750 kg/m2s. Results from previous work by the authors were used to select the data that correspond to the intermittent flow regime; generally, these points had qualities less than 25%. The pressure drop model previously developed by the authors for circular microchannels was used as the basis for the model presented in this paper. The model includes the contributions of the liquid slug, the vapor bubble, and the transitions between the bubbles and slugs. Slug frequency was estimated using a simple correlation for non-dimensional unit-cell length. The model predicts the experimentally measured pressure drops for the noncircular tube shapes under consideration with 90% of the predictions within ±28% of the measurements (average error 16.5%), which is shown to be much better than the predictions of other models in the literature. The effects of tube shape on condensation pressure drop are also illustrated in the paper.

An Expermentally Validated Model for Two-Phase Pressure Drop in the Intermittent Flow Regime for Noncircular Microchannels

2003 ◽  
Vol 125 (5) ◽  
pp. 887-894 ◽  
Author(s):  
Srinivas Garimella ◽  
Jesse D. Killion ◽  
John W. Coleman
Keyword(s):  
Pressure Drop ◽  
Flow Regime ◽  
Intermittent Flow ◽  
Average Error ◽  
Two Phase ◽  
Pressure Drops ◽  
Mass Fluxes ◽  
Tube Shape ◽  
Measured Pressure ◽  
Phase Pressure

This paper reports the development of an experimentally validated model for pressure drop during intermittent flow of condensing refrigerant R134a in horizontal, noncircular microchannels. Two-phase pressure drops were measured in six noncircular channels ranging in hydraulic diameter from 0.42 mm to 0.84 mm. The tube shapes included square, rectangular, triangular, barrel-shaped, and others. For each tube under consideration, pressure drop measurements were taken over the entire range of qualities from vapor to liquid at five different refrigerant mass fluxes between 150 kg/m2s and 750 kg/m2s. Results from previous work by the authors were used to select the data that correspond to the intermittent flow regime; generally, these points had qualities less than 25%. The pressure drop model previously developed by the authors for circular microchannels was used as the basis for the model presented in this paper. Using the observed slug/bubble flow pattern for these conditions, the model includes the contributions of the liquid slug, the vapor bubble, and the transitions between the bubble and slugs. A simple correlation for nondimensional unit-cell length was used to estimate the slug frequency. The model successfully predicts the experimentally measured pressure drops for the noncircular tube shapes under consideration with 90% of the predictions within ±28% of the measurements (average error 16.5%), which is shown to be much better than the predictions of other models in the literature. The effects of tube shape on condensation pressure drop are also illustrated in the paper.

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