Inlet Passageway Optimization of Immediate Heat Exchanger in an HTGR

The immediate heat exchanger is important for the heat utilization and hydrogen production in a very high-temperature gas-cooled reactor (VHTR). There is a 90-degree elbow passageway in the inlet passageway of immediate heat exchanger, contributing uneven flow distribution in circumference direction in the heat transfer area, which is harmful to the heat transfer tubes aging process. In this study, three inlet passageway optimization designs are put forward and their optimization effect is analyzed according to specific criterion by CFD. As the existence of spiral tube area would have coupling effect on inlet passageway flow, in the computation, the heat transfer area is assumed to be porous medium, in which the effect of heat transfer is taken into account as well. The result shows that installing flow distributer in the inlet passageway could make helium flow on circumference direction most homogenous.