EXPERIMENTAL AND NUMERICAL INVESTIGATION ON INLET FLOW DISTRIBUTOR OF INTERMEDIATE HEAT EXCHANGER OF AN HTGR

抄録

High temperature gas cooled reactor (HTGR), which has the characteristics of inherent safety, modular design and high outlet temperature, is considered as the most promising fourth generation reactor type. The intermediate heat exchanger (IHX) is the key equipment to produce hydrogen from HTGR, and the uniformity of the flow field among tube bundles has significant effects on the heat transfer performance and safety of the IHX. In this study, an experimental system was built to explore the effect of inlet flow distributors on flow uniformity, and the internal mechanism was explored through numerical simulation. The experimental results show that the velocity is various at different positions in the intermediate heat exchanger, and the uniformity of flow field without flow distributor is poor. Selecting the appropriate flow distributor can significantly improve the flow uniformity. The numerical simulation results show that the existence of the flow distributor makes the inlet flow split into two streams of fluid. One directly enters the tube bundle area, while the other enters the tube bundle area after flowing along the distributor for half a circle. The proportion of two streams of fluid affects the flow uniformity, while the flow distributors with different lengths adjust the proportion of two streams of fluid. Finally, an optimal shape of the inlet flow distributor is determined by combining the results of experiment and numerical simulation.