Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지
DOI QR코드

DOI QR Code

Characteristics of Autoignited Laminar Lifted Flames in Heated Coflow Jets of Carbon Monoxide/Hydrogen Mixtures

일산화탄소/수소 혼합기의 가열된 동축류 제트에서 자발화된 층류 부상화염의 특성

  • Choi, Byung-Chul (Environment & Plant Team, Korean Register of Shipping) ;
  • Chung, Suk-Ho (Clean Combustion Research Center, King Abdullah University of Science and Technology)
  • Received : 2012.01.06
  • Accepted : 2012.03.26
  • Published : 2012.06.01
Download PDF
⟨ Previous Next ⟩

Abstract

The characteristics of autoignited lifted flames in laminar jets of carbon monoxide/hydrogen fuels have been investigated experimentally in heated coflow air. In result, as the jet velocity increased, the blowoff was directly occurred from the nozzle-attached flame without experiencing a stabilized lifted flame, in the non-autoignited regime. In the autoignited regime, the autoignited lifted flame of carbon monoxide diluted by nitrogen was affected by the water vapor content in the compressed air oxidizer, as evidenced by the variation of the ignition delay time estimated by numerical calculation. In particular, in the autoignition regime at low temperatures with added hydrogen, the liftoff height of the autoignited lifted flames decreased and then increased as the jet velocity increased. Based on the mechanism in which the autoignited laminar lifted flame is stabilized by ignition delay time, the liftoff height can be influenced not only by the heat loss, but also by the preferential diffusion between momentum and mass diffusion in fuel jets during the autoignition process.

가열된 동축류 공기에서 일산화탄소/수소의 층류 제트에 대한 자발화된 부상화염의 특성을 조사하였다. 그 결과로 자발화가 발생하지 않는 영역에서는 제트속도의 증가에 따라 노즐부착화염에서 안정화된 층류 부상화염을 거치지 않고 바로 화염날림이 발생하였다. 자발화 영역에서, 질소 희석된 일산화탄소의 자발화된 부상화염은 산화제 내의 함유된 수분에 따른 점화지연시간의 변동으로 그 부상높이가 크게 영향을 받았다. 그리고 수소에 의한 저온 자발화 영역에서 자발화된 부상화염은 제트속도의 증가에 따라 부상높이가 감소하다가 증가하는 독특한 현상이 발생하였다. 점화지연시간에 의한 자발화된 층류 부상화염의 안정화 메커니즘을 기반으로, 그 부상높이의 거동은 점화 과정에서 발생하는 열손실의 영향뿐만 아니라 연료제트의 운동량과 질량의 선호 확산에 의하여 영향을 받을 수 있다는 것을 확인하였다.

Keywords

References

  1. Natarajan, J., Lieuwen, T. and Seitzman, J., 2007, "Effect of Hydrogen Addition on Autoignited Methane Lifted Flames," Combust. Flame, Vol. 151, pp. 104-119. https://doi.org/10.1016/j.combustflame.2007.05.003
  2. Natarajan, J., Kochar, Y., Lieuwen, T. and Seitzman, J., 2009, "Effect of Hydrogen Addition on Autoignited Methane Lifted Flames," Proc. Combust. Inst., Vol. 32, pp. 1261-1268. https://doi.org/10.1016/j.proci.2008.06.110
  3. Dong, C., Zhou, Q., Zhao, Q., Xu, T. and Hui, S., 2009, "Effect of Hydrogen Addition on Autoignited Methane Lifted Flames," Fuel, Vol. 88, pp. 1858-1863. https://doi.org/10.1016/j.fuel.2009.04.024
  4. Fotache, C.G., Tan, Y., Sung, C.J. and Law, C.K., 2000, "Effect of Hydrogen Addition on Autoignited Methane Lifted Flames," Combust. Flame, Vol. 120, pp. 417-426. https://doi.org/10.1016/S0010-2180(99)00098-X
  5. Walton, S.M., He, X., Zigler, B.T. and Wooldridge, M.S., 2007, "Effect of Hydrogen Addition on Autoignited Methane Lifted Flames," Proc. Combust. Inst., Vol. 31, pp. 3147-3154. https://doi.org/10.1016/j.proci.2006.08.059
  6. Kim, K.N., Won, S.H. and Chung, S.H., 2006, "Characteristics of Turbulent Lifted Flames in Coflow Jets with Initial Temperature Variation," Proc. Combust. Inst., Vol. 31, pp. 1591-1598.
  7. Choi, B.C. and Chung, S.H., 2008, "Characteristics of Methane Turbulent Lifted Flames in Coflow Jets with Initial Temperature Variation," Trans. KSME (B), Vol. 32 No. 12, pp. 970-976.
  8. Kim, K.N., Won, S.H. and Chung, S.H., 2007, "Characteristics of Laminar Lifted Flames in Coflow Jets with Initial Temperature Variation," Proc. Combust. Inst., Vol. 31, pp. 947-954. https://doi.org/10.1016/j.proci.2006.08.012
  9. Choi, B.C., Kim, K.N. and Chung, S.H., 2009, "Autoignited Laminar Lifted Flames of Propane in Coflow Jets with Tribrachial Edge and Mild Combustion," Combust. Flame, Vol. 156, pp. 396-404. https://doi.org/10.1016/j.combustflame.2008.10.020
  10. Chung, S.H. and Lee, B.J., 1991, "On the Characteristics of Laminar Lifted Flames in a Nonpremixed Jet," Combust. Flame, Vol. 86, pp. 62-72. https://doi.org/10.1016/0010-2180(91)90056-H
  11. Lee, B.J. and Chung, S.H., 1997, "Stabilization of Lifted Tribrachial Flames in a Laminar Nonpremixed Jet," Combust. Flame, Vol. 109, pp. 163-172. https://doi.org/10.1016/S0010-2180(96)00145-9
  12. Choi, B.C. and Chung, S.H., 2010, "Autoignited Laminar Lifted Flames of Methane, Ethylene, Ethane, and n-Butane Jets in Coflow Air with Elevated Temperature," Combust. Flame, Vol. 157, 2348-2356. https://doi.org/10.1016/j.combustflame.2010.06.011
  13. Choi, B.C., 2011, "Effect of ignition delay time on autoignited laminar lifted flames," Trans. KSME (B), Vol. 35 No. 10, pp. 1025-1031.
  14. Choi, B.C. and Chung, S.H., 2012, "Effect of Hydrogen Addition on Autoignited Methane Lifted Flames," Trans. KSME (B), Vol. 32 No. 1, pp. 75-81.
  15. Choi, B.C. and Chung, S.H., 2012, "Autoignited Laminar Lifted Flames of Methane/Hydrogen Mixtures in Heated Coflow Air," Combust. Flame, http://dx.doi.org/10.1016/j.combustflame.2011.11.016.
  16. Shaddix, C.R., 1999, "Correcting Thermocouple Measurements for Radiation Loss: A Critical Review," Proceedings of the 33rd National Heat Transfer Conference, Albuquerque, New Mexico.
  17. Kee, R.J., Rupley, F.M. and Meeks, E., 1996, "CHEMKIN-III: A Fortran Chemical Kinetics Package for the Analysis of Gas-Phase Chemical and Plasma Kinetics," SAND96-8216.
  18. Davis, S. G., Joshi, A. V., Wang, H. and Egolfopoulos, F., 2005, "An Optimized Kinetic Model of H2/CO Combustion," Proc. Combust. Inst., Vol. 30, pp.1283-1292. https://doi.org/10.1016/j.proci.2004.08.252
  19. Zeldovich, Ya.B., 1985, The Mathematical Theory of Combustion and Explosions, Consultants Bureau, pp. 1-185.