Active TPS for a blunt body behind a strong shock wave by means of subsonic counter-flow jets

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04192
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 19010:Fluid engineering-related
• Research Institution: Kyoto University
• Principal Investigator: Ohwada Taku 京都大学, 工学研究科, 教授 (40223987)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: Aerodynamic heating / Active TPS / film cooling / hypersonic flow / ILES

Outline of Final Research Achievements

The flow of an active thermal protection system exploiting subsonic counter-flow jets for wing leading edges of hypersonic vehicles is numerically studied on the basis of the three dimensional Navier-Stokes equations. The coolant air issuing from around the stagnation point as an array of three jets spreads over both the upper and the lower sides of the cylinder surface and about 40 ~ 60% cooling effectiveness is achieved in the range up to 5 degrees of angle of attack despite the enhancement of the mixing of the high temperature air and the coolant due to the occurrence of various three-dimensional fluid-dynamic instabilities. The numerical scheme is second order accurate but simple inclusion of high order polynomial approximation in the reconstruction enables the capturing of finer structure of the flow field. The validity of this simple ILES scheme is confirmed in the problem of the isotropic turbulence, where -5/3 power law is well reproduced.

Free Research Field

流体力学

Academic Significance and Societal Importance of the Research Achievements

軍事目的の極超音速飛翔隊は現在すでに一部の国では開発・配備されている。しか民間の極超音速機にはメンテナンスのしやすさや長寿命化が不可欠である。大阪ーシンガポール間を１時間で飛行する極超音速機のノーズや翼前縁は衝撃波背後の高温気体（１５００度）に晒されることから、その実現には動的な熱防御が求められる。これまでの研究ではLPMの超音速ジェットを使用した動的冷却が検討されたが本研究では冷媒の使用量がより少ない亜音速ジェットの場合が検討された。また数値解析法として簡便な陰的LES法が提案され、既存の方法よりも低コストで同等以上の性能を示唆する結果を得た。