Numerical and experimental investigation of wall heat flux in a GOX/GCH4 capacitive combustion chamber

This study investigates the thermal behavior of a prototype capacitive combustion chamber operating with GOX/GCH4 developed in the context of the Breeze program at The Exploration Company. Breeze is a reaction control system thruster designed for the Hilal lunar lander, and the prototype chamber serves to investigate the thermal response under long duration hot fire conditions. Because thermal transients in the chamber wall and the internal fluid occur on significantly different time scales, fully coupled fluid and structure simulations are computationally expensive. To address this, a weakly coupled numerical approach is proposed to predict the evolution of wall temperatures and heat fluxes. This methodology integrates combustion and flowfield modeling with transient conduction analysis in the chamber walls. Experimental tests are conducted on the prototype chamber to acquire thermal data, which are then compared with the numerical results. It is shown that combustion modeling has a strong impact on the generated wall heat flux and that the proposed weakly coupled methodology is capable of reproducing the transient thermal response of the combustion chamber with good agreement to experimental measurements while significantly reducing computational cost.