MASS FLOW RATE DISTRIBUTION AND PHASE SEPARATION OF R-22 IN MULTI-MICROCHANNEL TUBES UNDER ADIABATIC CONDITION

The present study investigated mass flow rate distribution and phase separation of R-22 in multi-microchannel tubes under adiabatic condition. The test section consisted of inlet and outlet headers with the inner diameter of 19.4 mm and 15 parallel multi-microchannel tubes. Each microchannel tube had 8 rectangular ports with hydraulic diameter of 1.32 mm. The key experimental parameters were the orientation of the header (horizontal and vertical), flow direction of refrigerant into the inlet header (in-line, parallel and cross flow), and inlet quality (0.1, 0.2, and 0.3). The effect of inlet quality on the mass flow rate distribution and phase separation in the microchannel tubes was negligible. The effect of the orientation of the header on the mass flow rate distribution and phase separation was the largest among the test parameters. Horizontal header showed better mass flow rate distribution and phase separation characteristics than vertical header. Both parallel and cross-flow conditions showed better mass flow rate distribution and phase separation than in-line flow condition.