Development of the refrigerant distributor for heat exchanger of air-conditioner. Visualization of gas-liquid two-phase refrigerant in the distributor using the neutron radiography

The distributor that divides a gas-liquid two-phase flow of refrigerant is widely used in the heat exchangers for air-conditioner. Recently, the performance of a refrigerant distributor became more important for the improvement of heat exchanger performance. To improve the refrigerant distributors, it is necessary to understand the behavior of two-phase flow of a refrigerant inside a distributor. The experiment of visualization by neutron radiography method, and image processing was conducted. It was observed that the liquid refrigerant was partly pooled in the bottom of the distributor and that the gas phase flowed up thorough the center of the liquid pool. From the image processing results, it was found that the instantaneous distribution ratio fluctuated sharply and periodically. (author)