Conference Year



Flow boiling, Pure refrigerant, Refrigerant-oil mixture, Pressure drop


This paper introduced a test facility to conduct both flow boiling and condensation test in a multi-channel tube, including structure designs in test section to maintain good and stable flow regime in multi-channels. It supports flow boiling and condensing testing at the same time. The refrigerant cycle was driven by a gear pump, liquid refrigerant flows from the gear pump, passes through an electrical pre-heater, evaporator and post-heater, then flow through water/glycol bath pre-condenser, condenser and post-condenser. Experimental data for pure R410A, R410A and lubricant RL32H mixture pressure drop in flow boiling is presented and analyzed in this paper. Inlet vapor quality was changing at 0.2, 0.4, 0.6 to 0.8 with 0.2 quality increase along the tube, mass fraction of lubricant was changing from 0%, 1%, 3% to 5%, and mass velocity of the pure and mixture varied from 100 to 700 kg s-1 m-2. The experiments have been conducted for average saturation temperature at 5ºC. Literatures on two phase flow boiling pressure drop for both pure refrigerant and refrigerant mixtures are carefully reviewed, popular published correlations are used in this study to evaluate test data. New two phase flow boiling pressure drop correlations for pure refrigerant and mixtures inside multi-channel tube are proposed. Some published data are used to validate new correlations.