Pseudo-three-dimensional topology optimization of heat and flow transfer in hydrocarbon fuel regenerative cooling channels

In supersonic combustion ramjet (SCRamjet), regenerative cooling channels face challenges from high heat flux and strict fuel quantity constraints. Moreover, the thermal boundary conditions of cooling channels are typically non-uniform, which may induce non-uniform fuel distribution. This can lead to serious waste of fuel cooling capability and even cause over-temperature conditions. To ensure heated wall safety, topological optimization of regenerative cooling channels is urgently needed to improve reasonable flow distribution and efficient utilization of cooling capacity. In this work, a three-layer pseudo-three-dimensional (pseudo-3D) model is developed and validated, accounting for turbulent flow and thermal property variations of hydrocarbon fuel. Topological optimization is further conducted on regenerative cooling channels under uniform and multiple non-uniform heat flux distributions. The three-dimensional (3D) numerical results of topology-optimized channels demonstrate that discrete ribs promote fluid divergence and convergence, enhancing heat transfer and optimizing flow distribution. The maximum wall temperature is reduced by 9.3%, 8.5%, and 13.17%, respectively. The Nusselt number is increased by 42.5%, 41.4%, and 49.3%, respectively. Finally, cylindrical pin-fins are used as basic structural units to construct the topological structure, avoiding unreasonable designs from the topology optimization process. This approach achieves a 6.9% reduction in maximum wall temperature. The research in this paper is expected to further support the optimized design of regenerative cooling channels.