Application of Transpiration Cooling for Hot Structures

Kurzfassung

Specific parts of re-entry vehicles are exposed to severe conditions. Thereby, the material’s capabilities can be exceeded by far and advanced cooling methods become necessary. Within the scope of this work, transpiration cooling was investigated in arc jet heated plasma flows by means of flat plate models. Screening tests pointed out, that transpiration cooling at the conditions tested is working well. Extensive testing at more severe conditions was done using three porous sample materials: Standard C/C with coolant flows parallel and perpendicular to the material’s fibre layers and highly porous C/C. Coolant gases used were air, argon, helium and nitrogen. Minimal optimal coolant mass flows of 0.5 g/s Ar, 0.2 g/s He and 0.4 g/s N2 were determined resulting in sample under surface temperature reductions of 50-60%. Altogether, sample under surface temperature reductions of 64% for He, 65% for Ar, 67% for air and 70% for N2 were detected. These test series verified that transpiration cooling can be applied successfully for hot structures at application relevant re-entry conditions.