Study of High-Frequency Combustion Instability of Rocket Engines Based on Off-Design Combustion Model

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03925
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 19020:Thermal engineering-related
• Research Institution: Chubu University
• Principal Investigator: KANDA Takeshi 中部大学, 理工学部, 教授 (50358545)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: ロケットエンジン / 高周波振動 / 燃焼 / 宇宙輸送

Outline of Final Research Achievements

In the liquid propellant rocket engine, the high-frequency combustion instability can happen and cause fatal destruction of a rocket engine combustor. The mechanism is not clear. I presumed that the propellant jets create semi-closed space on the injector plate, and off-design combustion induces the high-pressure and high-speed pressure change in the space. The objective is to validate the theory. We conducted experiments with propanol and oxygen for propellants. When combustion progress downstream of the propellant jets apart from the injector plate, we designated as normal combustion. Large-amplitude and quick pressure change was measured when combustion happened in the semi-closed space. Furthermore, number of repeats of combustion was large at the off-design combustion, comparing to the number at the normal combustion. The experimental results show that the instability will be caused by the mechanism of the theory.

Free Research Field

推進工学

Academic Significance and Societal Importance of the Research Achievements

ロケットエンジン燃焼器の高周波振動燃焼は半世紀以上、原因不明であった。この振動燃焼の原因の可能性が高い機構を検証することができたことは、宇宙輸送技術研究においては大きな成果である。
振動燃焼を回避することは、ロケットエンジンの開発および運用において大きな制約となっており、宇宙輸送のコストを押し上げる要因の一つでもあった。原因機構が解明されることにより、より柔軟でかつ低コストな宇宙輸送が可能となる。高周波振動燃焼は世界的な課題でもあるので、我が国が宇宙輸送技術の点で優位に立つことが可能となる。