Design and analysis of thermal hydraulic performance of compact heat exchanger for FDS-II auxiliary system

Abstract

One key issue of a fusion power plant is the requirement of highly efficient heat extraction from the primary loop to ensure the safety and reliability. The Dual-coolant Lithium Lead (DLL) breeder blanket of the FDS-II with a compact heat exchanger (CHE) is one design option for the power extraction system, and the Lithium Lead eutectic (LiPb) and helium gas are used as the thermal fluids. In this work, the flat and corrugated plate structures with SiCf/SiC composites and ODS steel were designed for the comparison of thermal performance. The heat transfer rate of the SiCf/SiC was 11.4% higher as compared to the ODS steel and was chosen as a candidate structural material. According to the design parameters of the DLL, effectiveness and the overall heat transfer coefficient for the corrugated structure increased up to 19.8% and 25.06% at the LiPb velocity of 0.099 m/s and increased up to 26.2% and 33.03%, when the velocity of the LiPb decreased to 0.012 m/s. The Nusselt number for the LiPb and helium gas was calculated for the convective heat transfer. The numerical results agreed well with the correlations within a deviation of ̴ 2%. In addition, pressure drop of the corrugation structure increased but it can be neglected as compared to the increase in the thermal performance. The concept of CHE with the SiCf/SiC structure could be applied to the design of intermediate heat exchanger working in a fusion power plant.