Two-phase refrigerant flow distribution in round tube heat exchanger manifolds has been investigated. Experimental data have been acquired in a heat exchanger test rig specially made for measurement of mass flow and phase distribution in the manifolds of compact heat exchangers. Horizontal round tube manifolds with 8 and 16 mm inner diameter and ten upward oriented heat exchanger tubes were used in the experiments, and CO2 and HFC-134a were used as refrigerants. The phase distribution results show that the vapor phase is preferentially distributed to the first heat exchanger tubes, while most of the liquid phase leaves through the tubes at the end of the manifold. The experimental data are compared to existing semi-empir¬ical models for phase split in T-junctions.

Units: Dual