ZHAI Fanshun, LI Xin, LUO Hongyi, TANG Xian, HE Hu, WU Weiming, NIU Changlei
In deep space exploration missions, the supply of energy presents a critical challenge. Due to the significant attenuation of sunlight intensity in the deep-space environment, the application of solar cells is limited. Consequently, radioisotope heat sources have emerged as a commonly used energy source. To improve the utilization efficiency of radioisotopes, this paper proposes a power supply system for deep-space probes that combines a radioisotope with a Stirling engine, aiming to investigate the overall efficiency optimization of the radioisotope heat source-Stirling engine system. Initially, three-dimensional models of the radioisotope heat source and the heat collector were created using 3D modeling software, and assembled to form the Stirling engine hot end. Thermal analysis was subsequently performed using finite element analysis software to ensure temperature matching between the thermally coupled components. Following this, a thermodynamic model of a free-piston Stirling engine was established based on the one-dimensional Stirling optimization software, Sage. The study systematically explored the influence of key parameters on system efficiency, including charge pressure, hot-end temperature, cold-end temperature, as well as the number and diameter of heater channels. The results indicate that increasing the charge pressure, raising the hot-end temperature, lowering the cold-end temperature, increasing the number of heater channels, and reducing their diameter contribute to enhancing both the efficiency and output power of the Stirling engine. These findings provide guidance for the design of efficient and reliable radioisotope Stirling engines.
