Visualization of Non-Equilibrium Two-Phase Flow

Recently, a few researchers have reported the presence of two-phase flow under subcooled conditions at the inlet of the capillary tube. In the present study, the effects of ambient temperature and R600a charge amount on the non-equilibrium two-phase state were investigated. The visualization results for most of the experiments demonstrated the presence of a non-equilibrium state at the inlet of capillary tubes of a refrigerator-freezer. The measured mass flow rates were compared with values predicted by Rasti et al. and Wolf and Pate empirical correlations to investigate accuracy of empirical correlations under the non-equilibrium state. Both correlations could predict the mass flow rate with large deviations under a non-equilibrium state. Finally, a new empirical correlation was introduced to calculate the equivalent thermodynamic quality under the non-equilibrium state. The modified version of Rasti et al.'s correlation showed that 78.3% of data under the non-equilibrium state fell within relative deviations of +/- 25%.