本研究旨在探討太空飛行器之空氣熱動力學的問題,該飛行器具有圓形 前緣,且飛行速度在超高音速範疇內。首先利用自家的 Navier- Stokes 解子, UNIS-UNS 程式,配合使用滑動邊界條件來模擬通過有球形鼻尖之圓柱。為驗證 本程式之正確性,在不同之努森數(Knusen number)和馬赫數(Mach number)條件 下,本程式的結果與 DSMC 法之結果做比較,獲致良好的一致性。其次,本研 究模擬了超高音速流通過歐洲實驗性太空艙(EXPERT),此流場範疇廣泛,含蓋 了太空艙降落時軌道之流場,並具有空氣膨脹時及熱化學的非化學平衡性質。 在考慮到飛行在超高音速時,空氣之解離及其對流場結構、氣動力和熱負載的 影響,針對完整之太空梭,本研究採用了三維計算流體力學(CFD)的分析。該分 析是未來研究之先導,並提供了科學領域之量化數據,可以做為改進超高音速 飛行器之設計參考。

The present work focuses on the problem of aerothermodynamics of space vehicles with rounded edges on the hypersonic segment of the flight trajectory. Firstly, the in-house Navier-Stokes solver, UNIC-UNS code, with the slip boundary condition is used to simulate the flows around a spherical- nosed cylinder at different Knudsen numbers and Mach numbers, and compared with DSMC computations for validation. The Navier-Stokes simulations are in good agreement with that of DSMC. The hypersonic flows over the European eXPErimental Re-entry Test-bed (EXPERT) model are then simulated for a wide range of flow regimes, which correspond to the expected descent trajectory with allowance for rarefaction and thermochemical nonequilibrium. Three dimensional CFD analyses are presented for the complete geometry of the capsules considering the air dissociation and its effects on the flow structure and on the force and thermal loads for the hypersonic segment of the flight as a precursor to the future studies and to provide the scientific community with quality data that can be used to improve tools for the design of hypersonic vehicles.

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