SiC porous ceramic with oriented pore microstructure for transpiration cooling

Abstract

Transpiration cooling is an active thermal protection technique with excellent cooling capacity for hypersonic vehicle, and its great development challenges the porous coolant medium seriously. In this paper, SiC porous ceramics with oriented pore microchannels have been fabricated by optimized biological template conversion technology for achieving directional management of coolant in transpiration cooling. The results indicate that SiC porous ceramics have high specific strength (99.3 MPa·cm³/g in radial direction, 343.9 MPa·cm³/g in axial direction), reasonable pore microchannels (diameter of 10～60 μm) and high directionality (tortuosity of 1.1～1.3). The independence of pore channels in this work is considerably superior to that of other porous materials. Additionally, the maximum fluid pressure occurs at the inlet during the permeability, which indicates that failure of ceramic can’t appear as long as fluid pressure at inlet is less than the mechanical strength of ceramic. These research results can provide important reference for optimizing transpiration cooling system.