Analysis of Thermal Transients for sCO2 Brayton Cycle Heat Exchangers

Abstract

The design of heat exchangers for use in a supercritical carbon dioxide (sCO2) Brayton cycle power converter must provide for acceptable performance for duty cycle events encompassing anticipated transients and postulated accidents. This paper presents the results of a comprehensive analysis of thermal transients for sCO2 cycle heat exchangers, with emphasis on the sodium-to-CO2 heat addition heat exchanger. A range of transients, from normal operation to severe accidents, were simulated with the coupled PDC and SAS4A/SASSYS-1 system level dynamic analysis computer codes. For each transient, the calculated change in the heat exchanger wall temperature is determined as a measure of the thermal loading.