Analysis and optimization of transpiration cooling performance for C/SiC composites with artificial holes

Constrained by the constraints of the C/SiC composites fabrication process, as well as cost and other factors, these composites exhibit attributes of low porosity and small pore sizes. The minute pores pose challenges in facilitating sufficient coolant supply and are susceptible to clogging. The feasibility of enhancing the transpiration cooling properties of C/SiC composites through the addition of artificial holes was analyzed. The structure and equivalent model of the artificial hole characterization unit were established. Flow ratios and effective permeability within the perforated composite were acquired. The effect of perforation method and mass flow rate on the effective heat transfer coefficient of composites was investigated. An empirical equation describing the variation of the heat transfer coefficient after perforation was fitted. Results show that for permeability characteristics, the dominant flow of cooling fluid occurs in the designed holes. In low-permeability materials with a permeability of 1×10⁻¹⁶ m², the proportion of fluid flow of the composites’ process hole drops to less than 0.1% after perforation, thereby rendering the flow of working material in this process hole negligible. Concerning heat transfer, adjusting perforation techniques can enhance composite material heat transfer efficiency. With the same permeability, altering perforation can boost body heat transfer coefficient by up to 154%.