Critical Speed Analysis of a 75 Ton Class Liquid Rocket Engine Turbopump due to Load Characteristics

75톤급 액체로켓엔진 터보펌프의 하중 특성에 따른 임계속도 해석

  • 전성민 (한국항공우주연구원 터보펌프팀) ;
  • 곽현덕 (한국항공우주연구원 터보펌프팀) ;
  • 홍순삼 (한국항공우주연구원 터보펌프팀) ;
  • 김진한 (한국항공우주연구원 터보펌프팀)
  • Received : 2011.11.29
  • Accepted : 2012.07.16
  • Published : 2012.08.01


Critical speed of high thrust liquid rocket engine turbopump is obtained through a rotordynamic analysis and a unloaded turbopump test is peformed for validation of the numerical model. The first critical speed predicted by the numerical analysis is correlated well with the test result for the bearing unloaded rotor condition only considering mass unbalance load. Using the previous rotordynamic model, critical speed variation is estimated as a function of varied bearing stiffness due to pump and turbine radial loads with relative angle difference. From the numerical analysis, it is found that the relative angle difference of pump and turbine radial loads greatly affects the critical speed. However, additional axial load reduces the effect derived from the relative angle difference of radial loads.


  1. Kim, J., Hong, S. S., Jeong, E. H., Choi, C. H., Jeon, S. M., "Development of a Turbopump for a 30 Ton Class Engine," Proceedings of the 43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, Cincinnati, OH, 2007, AIAA 2007-5516
  2. Jeon, S. M., Kwak, H. D., Yoon, S. H., Kim, J., "Rotordynamic Analysis of a Turbopump with the Casing Structural Flexibility," Journal of Propulsion and Power, Vol. 24, No. 3, May-June, 2008, pp.433-436
  3. 홍순삼, 김대진, 김진선, 김진한 "30톤급 액체로켓엔진용 터보펌프 실매질시험," 한국추진공학회지, 제13권, 제3호, 2009, pp.20-26
  4. 전성민, 곽현덕, 윤석환, 김진한 "고추력 액체 로켓 엔진용 터보펌프의 회전체 동역학 해석," 한국항공우주학회지, 제36권, 제7호, 2008, pp.688-694
  5. Jeon, S. M., Kwak, H. D., Yoon, S. H., Kim, J., "Turbopump Rotordynamic Analysis for a 75 ton Class Liquid Rocket Engine," 60th International Astronautical Congress 2009, Daejeon, Republic of Korea, IAC-09-C2.1.1, October 2009
  6. 홍순삼, 김진선, 김대진, 김진한 "75톤급 액체로켓엔진용 터보펌프 조립체의 상사매질 성능시험," 한국추진공학회지, 제15권, 제2호, 2011, pp.56-61
  7. Childs, D. W., "The Space Shuttle Main Engine High-Pressure Fuel Turbopump Rotor-dynamic Instability Problem," Journal of Engineering for Power, Vol. 100, No.1, 1978, pp.48-57
  8. Childs, D. W., Moyer, D. S., "Vibration Characteristics of the HPOTP (High Pressure Oxygen Turbopump) of the SSME (Space Shuttle Main Engine)," Journal of Engineering for Gas Turbines and Power, Vol. 107, 1985, pp.152-159
  9. Brune, C., Lassoudiere, F., "Rotordynamics of the Vulcain LH2 Turbopump Comparison between Test Results and Dynamic Analysis Calculations," Proceedings of 3rd International Conference on RotorDynamics, 1990, pp.353-360
  10. ISO Standard 1940, 1998, Mechanical Vibration - Balance Quality Requirements of Rigid Rotors, Part I : Determination of Permissible Residual Unbalance, 1st Ed.

Cited by

  1. A Study on the Turbopump Rotordynamic Characteristics due to Bearing Housing Structural Flexibility vol.18, pp.2, 2014,