Improving two-phase refrigerant distribution in the manifold of the refrigeration system

This study presents an experimental investigation to improve the two-phase refrigerant distribution in the manifold of the refrigeration (R-134a) system. The tests were conducted at the nominal inlet pressure of 173.5 kPa and mass flux of 130–145 kg/m2 s. Three different distributor configurations (Venturi tube connected with a smooth tube, Venturi tube connected with an internally–spirally micro-finned tube, and distributor within a roller) were selected. In the experiment, the effects of the outer-wall temperatures and pressures of the exits in the manifold, the cooling capacity (C) and coefficient of performance (COP) on two-phase flow distribution for the present study were displayed and discussed. In order to understand that flow distribution of two-phase refrigerant in the manifold, the flow visualization at the exit manifold of the distributor was made. It was found that the Venturi tube connected with the internally–spirally micro-finned tube got the best distribution efficiency, and resulted in the best coefficient of performance.