Pressure drop during condensation of R134a flowing inside a multiport minichannel

An experimental study of frictional pressure drop characteristics of R410A-oil mixture flow condensation inside aa 5 mm internally spiral grooved enhanced tube was performed to investigate the influence of oil concentration,vapor quality and mass flux on the frictional pressure drop.The experimental conditions include the condensation temperature of 40~C,the mass flux from 200 to 400 kg·m~(-2)·s~(-1),the heat flux from 4.21 to 8.42 kW·m~(-2),the inlet vapor quality from 0.3 to 0.9,nominal oil concentration from 0 to 5%.The test results show that the frictional pressure drop of R410A and R410Aoil mixture increases with mass flux and vapor quality;for R410A-ester oil RB68EP mixture,the influences of oil on frictional pressure drop are relevant with vapor quality.At the range of low and intermediate vapor qualities,the presence of oil will reduce the frictional pressure drop,which descends 29%maximally as the oil concentration increases from 0 to 5%;while at high vapor quality,on the contrary,the presence of oil will increase the frictional pressure drop,which enhances 8%maximally as the oil concentration increases from 0 to 5%.

Vapor quality

Mass flux

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Citations (0)

An experimental investigation on pressure drop of steam condensing in silicon microchannels

International Journal of Heat and Mass Transfer (2008)

Xiaojun Quan Ping Cheng Huiying Wu

Vapor quality

Hydraulic diameter

Mass flux

10.1016/j.ijheatmasstransfer.2008.03.028

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Citations (26)

Comparison and development of new correlation for adiabatic two-phase pressure drop of refrigerant flowing inside a multiport minichannel with and without fins

International Journal of Refrigeration (2017)

M. Mostaqur Rahman Keishi Kariya Akio Miyara

Mass flux

Vapor quality

Hydraulic diameter

Saturation (graph theory)

10.1016/j.ijrefrig.2017.06.001

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Citations (23)

Two-phase flow condensation heat transfer characteristics of R-134a inside three-dimensional cylindrical micropillar enhanced tube

International Journal of Refrigeration (2023)

Anil Kumar Ravi Kumar Arup Kumar Das

Mass flux

Vapor quality

Hydraulic diameter

Mass flow

10.1016/j.ijrefrig.2023.12.029

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Citations (6)

Experimental Investigation and Prediction on Pressure Drop during Flow Boiling in Horizontal Microchannels

Micromachines (2021)

Yan Huang Bifen Shu Shengnan Zhou Qi Shi

In this paper, two-phase pressure drop data were obtained for boiling in horizontal rectangular microchannels with a hydraulic diameter of 0.55 mm for R-134a over mass velocities from 790 to 1122 kg/(m2·s), heat fluxes from 0 to 31.08 kW/m2 and vapor qualities from 0 to 0.25. The experimental results show that the Chisholm parameter in the separated flow model relies heavily on the vapor quality, especially in the low vapor quality region (from 0 to 0.1), where the two-phase flow pattern is mainly bubbly and slug flow. Then, the measured pressure drop data are compared with those from six separated flow models. Based on the comparison result, the superficial gas flux jg is introduced in this paper to consider the comprehensive influence of mass velocity and vapor quality on two-phase flow pressure drop, and a new equation for the Chisholm parameter in the separated flow model is proposed as a function of the superficial gas flux jg. The mean absolute error (MAE) of the new flow correlation is 16.82%, which is significantly lower than the other correlations. Moreover, the applicability of the new expression has been verified by the experimental data in other literatures.

Vapor quality

Mass flux

Hydraulic diameter

Slug flow

Boiling point

Flow coefficient

Flow boiling

10.3390/mi12050510

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Citations (6)

Two-Phase Pressure Drop and Boiling Heat Transfer in a Single Horizontal Microchannel

ASME 4th International Conference on Nanochannels, Microchannels, and Minichannels, Parts A and B (2006)

Cheol Huh Moo Hwan Kim

With a single microchannel and a series of microheaters made with MEMS technique, two-phase pressure drop and local flow boiling heat transfer were investigated using deionized water in a single horizontal rectangular microchannel. The test microchannel has a hydraulic diameter of 100 μm and length of 40 mm. A real time observation of the flow patterns with simultaneous measurement are made possible. Tests are performed for mass fluxes of 90, 169, and 267 kg/m2s and heat fluxes of from 100 to 600 kW/m2. The experimental local flow boiling heat transfer coefficients and two-phase frictional pressure gradient are evaluated and the effects of heat flux, mass flux, and vapor qualities on flow boiling are studied. Both the evaluated experimental data are compared with existing correlations. The experimental heat transfer coefficients are nearly independent on mass flux and the vapor quality. Most of all correlations do not provide reliable heat transfer coefficients predictions with vapor quality and prediction accuracy. As for two-phase pressure drop, the measured pressure drop increases with the mass flux and heat flux. Most of all existing correlations of two-phase frictional pressure gradient do not predict the experimental data except some limited conditions.

Microchannel

Mass flux

Vapor quality

Hydraulic diameter

10.1115/icnmm2006-96101

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Citations (4)

Heat transfer and pressure drop during condensation of R152a in circular and square microchannels

Experimental Thermal and Fluid Science (2013)

Na Liu Jun Ming Li Jie Sun Hua Sheng Wang

Hydraulic diameter

Mass flux