AERO THERMAL AND STRUCTURAL PERFORMANCE OF A COBALT BASE SUPER ALLOY THERMAL PROTECTION SYSTEM AT MACH 6.6

摘要

A flightweight, metallic thermal protection system (TPS) applicable to reentry and hypersonic vehicles was subjected to multiple cycles of both radiant and aero-thermal heating in order to evaluate its aerothermal performance and structural integrity. The TPS consisted of a 108.0-cm by 152.4-cm (42.5-in. by 60-in.) corrugation-stiffened skin and supports fabricated from a cobalt-based alloy (L-605), a 5-cm (2-in.) thick microquartz insulation blanket enclosed in an inconel foil, and a titanium sheet which simulated the vehicle primary structure. The TPS was subjected to 32 thermal tests, 13 of which were aerothermal tests conducted in the Langley 8-foot high-temperature structures tunnel at a nominal free-stream Mach number of 6.6. The TPS was heated by the radiant lamps for a cumulated total of 6.59 hours at a surface temperature of approximately 1145 K (2060° R) and was tested in the stream for a cumulated total of 423 sec. Good structural integrity and thermal performance were demonstrated by the TPS under both a radiant and aerothermal heating environment typical of a shuttle entry. The shingle-slip joints effectively allowed for thermal expansion of the panel without allowing any appreciable hot gas flow into the TPS cavity. The TPS also demonstrated good structural ruggedness.