Design and Thermo-Structural Analysis of the Interface between Subscale Versions of Carbon-Carbon (C-C) Nozzle Divergent to Metallic flange hardware for a Ground Simulation Test

摘要

Carbon-carbon and carbon fiber reinforced materials are promising materials for use in space applications, due to their excellent thermal and mechanical properties. Carbon-carbon (C-C) is the material which is having lower density and lower coefficient of thermal expansion compared to metals under higher temperature environment. Their dimensional stability, low outgassing and insignificant change in mechanical properties at elevated temperatures make C-C as ideal candidate for various space structural applications especially the throat and divergent of Nozzle in the Solid Motor. Carbon-carbon nozzle divergent extension with supersonic film cooling provides performance improvement and ultimately payload gain. To demonstrate the performance of supersonic film cooling concept with 2-D carbon-carbon nozzle divergent, a sea level static test was conducted with a lesser Aluminium fuel content in a sub scale Solid Motor simulating the flow condition closer to that of liquid engine. The motor was configured w ith 17 area ratio nozzle (metallic configuration up to area ratio 10 and remaining per as C-C). A supersonic injection module was used to inject gaseous hydrogen at 2 bar pressure through the conduit mounted at AR10. Design of the C-C divergent to metallic fanged joint was carried out according the preload capability of the joint at higher temperature for a 10 sec burn time. Thermo structural analysis of this set up was carried out using the temperature distribution from the thermal analysis. Loads were applied in these load steps viz., i) Preload ii) varying temperature at 10 sec and iii) varying internal pressure. This paper covers the details of the thermo structural analysis and the results viz., preload loss, final bolt stress, O-ring compression, stresses in the C-C and metallic flange, gap opening at Hydrogen injection point etc. and also covered the details of the post test inspection.