High precision modeling of a self-pressurized oxidizer flow in a rocket engine

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K04555
• 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: Muroran Institute of Technology
• Principal Investigator: NAKATA DAISUKE 室蘭工業大学, 大学院工学研究科, 助教 (90571969)
• Co-Investigator(Kenkyū-buntansha): 渡邉 力夫 東京都市大学, 理工学部, 准教授 (20308026)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 混相流 / 自己加圧 / ボイド率 / ハイブリッドロケット

Outline of Final Research Achievements

Nitrous oxide (N2O) has a high vapor pressure (~ 7MPa) at room temperature and is capable of self-pressurizing discharge, so it is widely used as a hybrid rocket oxidant. On the other hand, it is difficult to predict the flow rate of gas-liquid two-phase flow, and it is desirable to identify the flow mode and model the pressure drop characteristics. In this study, we first visualized the 7MPa high-pressure pipeline, which was difficult in the past, and clarified the bubble flow velocity and bubble diameter with a high-speed camera. We also discussed the relationship between the void ratio and the pressure drop characteristics using the capacitance type void ratio. In the numerical calculation, we found a qualitatively good agreement with the experimental results regarding the relationship between the pressing pressure and the injector discharge coefficient.

Free Research Field

航空宇宙用エンジン

Academic Significance and Societal Importance of the Research Achievements

気液二相流への実験的アプローチは広く行われているが，とりわけ1-7MPaでの高圧管路における高圧条件下での流動様式を明らかにすることは困難が大きいものであった．今後の展開としては，亜酸化窒素は蒸発潜熱も大きいため，気泡径に及ぼす熱力学的な効果についても学術的調査が必要と考えられる．
社会的意義としては，小型ロケットエンジンで広く用いられている亜酸化窒素の流量予測モデル確立に向け，多くの実験データを残し，国際学会においても多くの議論を喚起した．