Combuarion oscillation dynamics of liquid rocket engine combustor with a pintle injector

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K04558
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 24010:Aerospace engineering-related
• Research Institution: The University of Tokyo
• Principal Investigator: Nakaya Shinji 東京大学, 大学院工学系研究科(工学部), 准教授 (00382234)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 液体ロケットエンジン / ピントル型噴射器 / 燃焼不安定性 / 動的モード分解 / データ駆動型アプローチ / マルチフラクタル解析

Outline of Final Research Achievements

In rocket engine development, it is important to understand the combustion behavior and the mechanism of combustion instability. In the present study, the combustion behaviors were observed in a model combustor with a pintle injector. A transition from unstable combustion to stable combustion, and vice versa were observed in the experiments. The oscillation states were analyzed by data-driven approaches using analytical methods such as high-speed image-based dynamic mode decomposition, a nonlinear analysis focusing on fractality, and unsupervised learning. The results showed that stable combustion was more complex than unstable combustion, containing various scales of vibration. The comparison of atomization characteristics of different injectors clarified a mechanism for an increase in the We number resulted in the combustion efficiency.

Free Research Field

航空宇宙工学

Academic Significance and Societal Importance of the Research Achievements

ロケットエンジンの低コスト化，安全性向上に向けて，炭化水素燃料を用いた場合の燃焼特性を理解することは重要である．また，ロケットの再使用化や衛星の軌道要求の高まりから，高効率でのスロットリング性能を持つピントル型噴射器に注目が集まっている．本研究の結果からデータドリブン手法を用いた，振動状態の把握の可能性が示され，将来的に振動の抑制や制御に応用することができると考えられる．さらに，本研究で得られた微粒化特性と燃焼挙動関連性は，噴射器設計において有用な指標となりうる．