Study The Influence Of Filaments On PODS-Ⅳ Heat Transfer And Structure’s Performance

Liquid hydrogen, liquid oxygen and liquid methane are used as energy supply sources; or liquid nitrogen, liquid helium as cold supply sources in the aerospace industry. The safe and efficient storage of cryogenic propellants has an important economic value, and is directly related to the development of national advanced science and technology. As a vital cryogenic propellant passive thermal protection technology, Passive Orbital Disconnect Strut has the passive orbit disconnected feature and has a vital significance on reducing the on-orbit heat leakage of cryogenic propellants.Aiming at the problem that PODS-III easily forms thermal shorting under side-loads, the structure and heat transfer characteristics of PODS-â…£ with filaments were studied.(1) Thermal mechanical quality factor analysis was applied to the related composite materials of PODS-â…£, S-glass/epoxy for launch tube, graphite/epoxy for orbit tube and filaments were determined. On this basis, PODS-â…£ three-dimensional models under different filament diameters were established, the heat transfer quantities of PODS-â…£ without thermal shorting were obtained by numerical calculation, and the diameter of the filament was determined by comparative analysis,then, PODS-â…£ model was determined.(2) The side-loads resistance abilities of PODS-â…£ with filaments and PODS-III without filaments were numerically calculated respectively. Then the critical values of side-loads applied at different locations were obtained without thermal shorting, as well as the conical surface deflections. The results show that, PODS-â…£ has better side-load resistance ability than PODS-III, and reduces the heat leakage of the cryogenic vessel through the strut of PODS-â…£; with the increase of distance between side-load applied location and cold rod-end, the side-load critical value of PODS-â…£ and PODS-III increases accordingly without thermal shorting, and the longer distance between the side-load applied location and the cold rod-end will have a less impact on the strut of thermal shorting; PODS-â…£ has better support ability and space applicability.(3) Combining with the temperature conditions of on-orbit stage, the effect of temperature on the PODS-â…£ side-load resistance ability was researched.Thermal-structure coupling analysis of PODS-â…£ was conducted, and compared with the results under static structural analysis. The results showed that the side-loads of PODS-â…£ which can bear decreases under thermal-structure coupled action. Since the micro-expansion of graphite/epoxy composites with the decrease of temperature leads to the relaxation of filaments, the side-load resistance ability decreases. The results are in good agreement with theoretical analysis.