distributor, orientation, two-phase, flow regime, visualization
Maldistribution of refrigerant two-phase flow in a DX evaporator is almost inevitable in real application because of the different properties of liquid and vapor. One of the main reasons for this is phase separation due to the effect of gravity. For vertical orientation, the influence of gravity on the operation of distributors is small. However, horizontal installation is more likely to be affected by gravity when the flow is not homogeneous. This paper presents an evaluation of the performance of a refrigerant distributor at three different orientations: horizontal, vertical upwards, and downwards. For each direction, the expansion device, distributor, and evaporator are connected in the same way to reduce the effect of test facility on the flow distribution. A transparent distributor with identical geometry of an original version is built for the purpose of visualization. Both distributors are tested under the same working conditions to investigate the individual difference. Results show that two-phase distribution at the horizontal orientation is similar to the vertical results, indicating no effect of gravity for the tested working conditions. However, the difference in individual distributor circuit due to manufacture will result in maldistribution in some degree.