연소실 내 동축형 2-유체 분무의 이론적 모델

Theoretical Model of Coaxial Twin-Fluid Spray In a Liquid Rocket Combustor

  • 발행 : 2002.06.01

초록

액체로켓엔진에 사용되는 2-유체 동축형 분사기의 분무 연소 특성을 수치적으로 해석하였다. 가스 역학적 상호작용에 의한 미립화 및 그에 따른 물리 현상들에 대해 유동에 대한 보존방정식과 이론식들을 적용, 수치화하여 액체 제트의 상태, 제트의 속도, 제트의 붕괴길이, 액적의 크기등을 예측 하였으며, 액체제트 분사공 크기에 따른 미립화의 변화를 고찰하였다. 모델 검증을 위하여 액체 제트의 접촉길이와 액적의 크기를 기존의 실험결과와 비교하였으며, 그 결과 정성적으로 일치함을 나타내었다. 액체 제트의 접촉길이는 분사공의 직경이 증가할수록 짧아지고 액적의 크기도 분사공의 직경이 증가할수록 작아진다. 액체 제트는 박리율 증가에 따른 분무화에 의하여 단면적이 감소되며, 그에 따른 질량유속의 보존과 가스로부터의 운동량 화산에 따라 미립화가 활발해지는 영역으로부터 그 속도가 급속히 증가된다.

A theoretical study of spray and combustion characteristics due to coaxial twin-fluid injection is conducted to investigate the effects of liquid jet property, droplet size, contact length and liquid jet velocity. Model is properly validated with measurements and shows good agreement. Prediction of jet contact length, droplet size, liquid jet velocity reflects genuine features of coaxial injection in physical and practical aspects. Both the jet contact length and tile droplet size are reduced in a linear manner with an increase of injector diameter. Cross sectional area of liquid intact core is reduced with augmented jet splitting rate, thus the jet is accelerated to maintain the mass continuity and with an assistant of momentum diffusion by burnt gas.

키워드

참고문헌

  1. R.D Sutton, 'Spay Cmbustion Processes in Seady and Non-Seady Flow system,' Ph.D. Thesis, Department of Mchanical Engineering, University of California, Berkeley, California, September 1971
  2. R.D Sutton, M.D Schuman, W.D Chadwick, 'Operating Manual for Coaxial Injection Combustion Model', 1974
  3. G.M. Feath 'Current Status of Droplet and Liquid Combustion', Combust Sci. Vol 3. pp 191-224, 1977 https://doi.org/10.1016/0360-1285(77)90012-0
  4. Donald J. Hautman, 'Spray Characteristics of Liquid/Gas Coaxial Injections with The Center Liquid Swirled', Atomization and Spray, vol.3, pp, 373-387, 1993 https://doi.org/10.1615/AtomizSpr.v3.i4.20
  5. P.Y Liang, R.J. Jensen and Y. M. Chang, 'Numerical Analysis of SSME PreburnerInjector Atomization and Combustion Process,', AIAA Paper 86-0454, 24th Aerospace Sciences Meeting, January 6-9, Reno, Nevada, 1986
  6. A. Prezkwas, S. Chuech and A. K. Singhal, 'Numerical Modeling for Primary Atomization of Liquid Jets,' AIAA Paper 89-0163, 27th Aerospace ciences Meeting, January 9-12, 1989, Reno, Nevada 1989
  7. M.G.Giridharan, J.G. Lee, A. Krishnan, A.J. Przekwas 'A Numerical Model For Coupling Between Atomiztion And Spray Dynamics In Liquid Rocket Thrust Chamber', AIAA, 1992
  8. A. Crespo, A. Linan, 'Unsteady Effects in Droplet Evaporation and Combustion', Combustion Science and Technology, Vol.11, pp9-18, 1975 https://doi.org/10.1080/00102207508946679
  9. Reitz R.D and Bracco F.V, 'Mechanism of Breakup of Round Liquid Jets,' In Encyclopedia of Fluid Mechanics, Gulf Pub, Houston, TX, pp 233-249, 1986
  10. M.C. Yeon and L.W. Chen, 'On Drag of Evaporation Liquid Droplets', Combustion Science and Technology, Vol.14, pp147-154, 1976 https://doi.org/10.1080/00102207608547524
  11. Alex B. Liu, Daniel Mather, and Rolf D. Reitz 'Modeling the Effects of Drop Drag and Breakup on Fuel Sprays', SAE Paper 930072, March 1-5, 1993
  12. Chigier, N and Eroglu, H,,'Atomization of Liquid Jets from Injection Elements in Liquid Rocket Combustion Chamber,' Carnegie mellon Univ. NASA Report, MSFC, Grant NAG8-126, Sep. 1990
  13. S.P Lin, 'Regimes of Jet Breakup and Breakup Mechanisms (Mathematical Aspects)', Clarkson University, Potsdam
  14. J.C.Lasheras, E. Villermaux and E.J. Hoppinger, 'Breakup and Atomization of a Round Water Jet by a High-Speed Annular Air Jet', Fluid Mech, vol 357, pp351-379, 1998 https://doi.org/10.1017/S0022112097008070
  15. R.D. Reitz and R.Diwakar 'Effect of Drop Breakup on Fuel Sprays', SAE Paper 860469, February 24-28, 1986