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2021 Fiscal Year Final Research Report

Investigation for Speed Ratio Dependence of Rarefied Aerodynamics Using Hypersonic Rarefied Wind Tunnel

Research Project

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Project/Area Number 18K04565
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 24010:Aerospace engineering-related
Research InstitutionJapan Aerospace EXploration Agency

Principal Investigator

Ozawa Takashi  国立研究開発法人宇宙航空研究開発機構, 研究開発部門, 主任研究開発員 (70567544)

Co-Investigator(Kenkyū-buntansha) 鈴木 俊之  国立研究開発法人宇宙航空研究開発機構, 宇宙科学研究所, 主任研究開発員 (20392839)
Project Period (FY) 2018-04-01 – 2022-03-31
Keywords航空宇宙工学 / 希薄気体力学 / 希薄風洞 / 数値解析 / DSMC / 極超音速流
Outline of Final Research Achievements

Rarefied aerodynamics need to be accurately estimated for super low altitude test satellites, planetary atmospheric entry, Air Breathing Ion Engine (ABIE), and so forth. This research aims to develop a measurement system for hypersonic rarefied aerodynamics and study rarefied aerodynamic dependence on speed ratio by carrying out both measurements in the hypersonic rarefied wind tunnel (HRWT) and direct simulation Monte Carlo (DSMC) numerical analyses.
Lowering surface temperature results in lowering surface reflection speed, and thus, in order to improve the speed ratio in HRWT, we have first developed a cooling system for models using liquid nitrogen. Second, cooling pressure tube models have been tested in HRWT. Third, we carried out DSMC computations to investigate the dependence of tube pressure on speed ratio. We found that the speed ratio becomes two times higher in the HRWT test section with the cooling system, and pressure becomes higher along with the increase of speed ratio.

Free Research Field

航空宇宙工学

Academic Significance and Societal Importance of the Research Achievements

連続流領域と自由分子流領域の狭間である希薄気体領域の計測システムの確立は、両領域のモデルを結合する上でも必要不可欠である。希薄空力特性は表面モデルに依存する。近年、表面モデルの物質依存性や気流組成依存性は評価されつつあるが、速度比依存性に関しては計測データが乏しい。本研究では、世界に先駆けて希薄気体の速度比依存性計測システムを構築し、速度比依存性解明に向けたデータ取得を行った。希薄空力特性の計測及び数値計算の融合は、非常に独創的である。本研究によるデータの検証を進め、速度比依存性を解明することにより、希薄流領域を利用する宇宙ミッションの空力特性予測の精度を高めることが期待できる。

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Published: 2023-01-30  

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