Pressure drop characteristics for two-phase flow of FC-72 in microchannel

Abstract

In this paper, an experimental study on two-phase flow pressure drop of refrigerant FC-72 is carried out in a microchannel. The microchannel has a width and depth of 0.45 and 0.2 mm respectively, and comprises 15 parallel channels with a length of 60 mm. The experiment is conducted under the condition of mass flux of 100.3–458.0 kg/m2s and heat flux of 3.2–49.0 kW/m2. This study analyzed the pressure drop characteristics for two-phase flow by using a separated flow model. To predict the frictional pressure drop, two-phase frictional multiplier obtained from experiments is compared with the existing correlations. The experimental results show that two-phase frictional multipliers rely heavily on the vapor quality. Fractional pressure drop increases as the vapor quality increases. However, the rate of increase in the high vapor quality region decreases as the vapor quality increases. Based on pressure drop characteristics obtained from the experiments, a new correlation is proposed to predict the frictional pressure drop. Two-phase multiplier is modified with the dimensionless parameters such as Reynolds number, Weber number, and Martinelli parameter. The newly developed correlation predicts the experimental results well within a mean absolute error of 8.0%.