Transpiration cooling for additive manufactured porous plates with partition walls

Transpiration cooling is an effective method to protect high heat flux surfaces such as rocket combustion chambers. However, this technology is currently not applicable for turbine airfoils as the strength of traditional sintered porous material was too low and the pore structure was uncontrollable. Consequently, developing porous media with high mechanical strength and precise geometry is important for transpiration cooling. Present study utilized the Selective Laser Melting Additive manufacturing technology to fabricate metal porous plates for transpiration cooling. Reinforcing partition walls were applied to the porous plate to further enhance the mechanical strength. Both cooling efficiency and mechanical properties were evaluated for the additive manufactured porous plates and compared to the traditionally sintered porous plate. The experimental results showed that the transpiration cooling efficiencies of the additive manufactured porous plates with partition walls approached to that of sintered porous plate, which approached to 0.7 when coolant blowing ratio was 2%. The presence of solid partition walls did not affect the cooling efficiency even for a high blocking ratio of 60%. The mechanical property was significantly improved by additive manufactured porous plate with partition walls. The ultimate tensile strength (UTS) increased by 440% compared to sintered porous material. Such results demonstrated that additive manufacturing and reinforced partition walls might be potential solutions to enhance the mechanical strength of transpiration cooling.