Experimental and numerical study of flow distributor of intermediate heat exchanger in high temperature gas-cooled reactor

Abstract

The intermediate heat exchanger (IHX) is a key component in the heat-utilization system of a high temperature gas-cooled reactor. However, the elbow at the bottom of the IHX results in uneven flow and temperature fields among the heat exchange tube bundle, leading to fatigue damage to the IHX. This study experimentally and numerically investigates the mechanism by which a flow distributor improves the uniformity of the flow field, and selects the distributor with the best effect on improving the uniformity. The results show that the distributor divides the flow into two parts, and the length and the angle of the distributor influence the uniformity by influence the ratio of the two parts. As the length increases, the uniformity first increases and then decreases at any angle. When the length is short, the uniformity increases with the increasing angle. When the length is long, the uniformity decreases with the increasing angle. With an appropriate size of flow distributor, the squared coefficient of variation decreases from 0.35 to 0.034, and the non-uniformity decreases by 90.2%. This study also proposes a semi-empirical formula based on dimensionless numbers to predict the appropriate size for a flow distributor.