Study on iterative algorithm of full plate cross-flow and counter-flow printed circuit heat exchanger for fluoride-salt-cooled high-temperature advanced reactor

In the concept of Fluoride-Salt-cooled high-Temperature Advanced Reactor (FuSTAR), the Printed Circuit Heat Exchanger (PCHE) is mainly considered in its supercritical carbon dioxide (S–CO2) Brayton cycle secondary loop. The design of the PCHE is based on the property of working fluid provided by the Brayton cycle system design. Therefore, a fast and iterative PCHE design method is required. In this study, a mathematical model based on Picard's iterative method is proposed. The model can solve full plate temperature field with complex boundary conditions and initial values including cross-flow and counter-flow PCHE in parallel. Based on FuSTAR Brayton cycle design conditions, three sizes of cross-flow and counter-flow PCHEs are simulated respectively by the mathematical model. Compared with Computational Fluid Dynamics (CFD) models, a one and three-dimensional coupling model and a three-dimensional model, the mathematical model reduced the computing time from 1 to 10 h to 1–10 s, and the maximum temperature mean deviation is 18.6% for the smallest size case because of the edge effect and local disturbance, but 8.4% for other size. Taking secondary loop recuperator design as example, the computing speed and accuracy of the mathematical model can meet the design requirements of FuSTAR PCHE.