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Research Article

Preliminary Numerical Study on the Combustion Efficiency of a Multi-Slit Type Gas-Liquid Pintle Injector
Subeom Heoab
,
Youngbin Yoonac*
,
Bok Jik Leeac
aDepartment of Aerospace Engineering, Seoul National University, Seoul 08826, Korea
bFuture Aeropropulsion Research Team, Korea Aerospace Research Institute, Daejeon 34133, Korea
cInstitute of Advanced Aerospace Technology, Seoul National University, Seoul 08826, Korea
*Corresponding Author
30 November 2025. pp. 17-26
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Abstract

The momentum ratio between oxidizer and fuel is widely known to affect the combustion efficiency of pintle injectors for liquid rocket engines. Based on TRW’s hot firing test results, many subsequent studies have set the momentum ratio to unity when designing pintle injectors to obtain maximum combustion efficiency. However, recent studies have shown that the highest combustion efficiency of gas-liquid pintle injectors was observed at momentum ratios other than 1. Therefore, this study revisits the effects of momentum ratio on the combustion efficiency of a gas-liquid pintle injector within the range of 0.3–4.4. The results show that the peak efficiency did not occur at a momentum ratio of 1, conflicting with TRW’s design recommendations. Furthermore, the effects of blockage factor and mixture ratio are also investigated.

Keywords
Pintle Injector
Combustion Efficiency
Momentum Ratio
Liquid Rocket Engine
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Information
  • Publisher :The Korean Society of Propulsion Engineers
  • Publisher(Ko) :한국추진공학회
  • Journal Title :Journal of Propulsion and Energy
  • Journal Title(Ko) :Free Open Access International Journal on Propulsion and Energy Science and Technology
  • Volume : 5
  • No :2
  • Pages :17-26
  • Received Date : 2025-08-07
  • Revised Date : 2025-09-02
  • Accepted Date : 2025-09-18
  • DOI :https://doi.org/10.6108/JPNE.2025.5.2.017
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