Supercritical CO2 Brayton cycle at different heat source temperatures and its analysis under leakage and disturbance conditions

Abstract

Supercritical carbon dioxide (SCO2) Brayton cycle has been widely used in a variety of industrial settings. In this work, three commonly used SCO2 Brayton cycle dynamic numerical models at different heat source temperatures are built with MATLAB and Simulink software, and the key parameters of three commonly used Brayton cycle models (recompression, reheating and intermediate cooling) are compared when the heat source temperature changes from 813 K to 2,113 K. And The steady-state values of the simulation system and experimental values are verified. Under the same component parameter setting, the recompression of the model cycle efficiency at different heat source temperature is generally the highest, followed the reheating mode, and the lowest in the intercooling model. With the increase of heat source temperature, the efficiency of the recompression model gradually improve. Under 5 % leakage condition, the recycling efficiency of the recompression model increases by 2.58 %, while the efficiency of the reheating model and the intercooling model decreases. Sinusoidal disturbance with the amplitude of 12.5 K and period of 8 s is added at the inlet of HTR hot side, compared with intercooling model and reheating model. The efficiency fluctuation amplitude of the recompression model is large, but the power generation is more stable.