Numerical study on the performance of pintle controlled solid rocket motor based on fluid-thermal-structure interaction

To accurately predict the performance of pintle controlled solid rocket motors (PCSRM), a fluid-thermal-structure interaction (FTSI) numerical model is developed. First, by comparing the FTSI method, conventional numerical method, and empirical formulas, the dynamic performance of PCSRM under FTSI effects was investigated. Next, the effects of pintle stroke and pintle material on PCSRM performance were analyzed. Finally, the underlying mechanism of FTSI effects on PCSRM performance was revealed. The results show that the FTSI method successfully captures the influence of pintle deformation on PCSRM performance. Specifically, compared to the conventional numerical method, the thrust coefficient increases by 0.20 %–1.51 %, the thrust increases by 0.47 %–6.22 %, and the total pressure recovery coefficient decreases by 1.97 %–5.02 %. Severe convective heat transfer within the PCSRM rapidly raises the temperature of the pintle head above 2300 K, causing significant FTSI deformation that reduces the equivalent throat area by up to 9.90 %. Additionally, the FTSI deformation of the pintle alters the flow field structure, resulting in a maximum increase of 15.46 % in chamber pressure and 5.12 % in mass flow rate. The FTSI method better reflects real conditions, providing reliable support for the precise prediction of PCSRM performance.