- Volume 17 Issue 1
A Comparative Study Between Diffusive-thermal and Buoyancy-driven Self-excitations in Laminar Free Jet Flames with Applied DC Electric Fields
직류전기장이 인가된 층류제트화염에서 물질 -열 확산과 부력에 의한 진동비교에 관한 연구
- 한종규 (부경대학교 기계공학과) ;
- 윤성환 (부경대학교 친환경 수송시스템연구소) ;
- 박정 (부경대학교 기계공학과) ;
- 권오붕 (부경대학교 기계공학과) ;
- 김태형 (한국전력연구원 수화력 발전팀) ;
- 박종호 (충남대학교 기계공학과)
- Received : 2012.02.17
- Accepted : 2012.03.21
- Published : 2012.03.30
Experimental study on comparison of diffusive-thermal self-excitation with buoyancy-driven one due to accumulation of partially premixed, preheated mixture in front of edge flame was conducted in horizontally and vertically injected laminar free-jet flames with an applied DC electric field of -10 kV. The application of horizontal injection method with the DC electric field to jet flames was experimentally designed to suppress heat-loss-induced self-excitation and thereby to highlight the definite difference between both diffusive-thermal and buoyancy-driven self-excitations with the same order of O(1.0 Hz), in that diffusive-thermal self-excitation has not been so far found experimentally in laminar jet flames. Flame stability maps in vertically and horizontally injected jet flames are presented. The distinct modes of individual self-excitation are shown to be well described by their own phase diagrams. The results show that buoyancy-driven self-excitation due to the accumulation of partially premixed, preheated mixtures in front of edge flame is branched from the buoyancy-induced self-excitation with O(10 Hz) due to a flame flicker. Once the buoyancy-driven self-excitation appears, it suppresses buoyancy-induced as well as diffusive-thermal self-excitation. The key characteristics for individual self-excitation are discussed and their functional dependencies of Strouhal number upon related physical parameters are also presented.
Supported by : 한국연구재단
- S. H. Won, S. H. Chung, M. S. Cha, B. J. Lee., "Lifted flames stabilization in developing and developed regions of coflow jets for highly diluted propane", Proc. Combust. Inst. Vol. 28, 2000, pp. 2093-2099.
- S. H. Won, J. Kim, M. K. Shin, S. H. Chung, O. Fujita, T. Mori, J. H. Choi, K. Ito., "Normal and microgravity experiment of oscillating lifted flames in coflow", Proc. Combust. Inst. Vol. 29, 2002, pp. 37-44.
- S. H. Yoon, J. K. Han, J. Park, J. H. Yun, S. I. Keel., "Self-excitation in laminar lifted flames diluted with nitrogen", Combust. Flame. Vol. 158, 2011, pp. 1960-1969. https://doi.org/10.1016/j.combustflame.2011.02.020
- M. Füri, O. Papas, P. A. Monkewitz, "Non-premixed jet flame pulsations near extinction", Proc. Combust. Inst. Vol. 28, 2000, pp. 831-838.
- Kurdyumov, V. and Matalon, M., "Stabilization and onset of oscillation of an edge-flame in the nearwake of a fuel injector", Combust. Inst. Vol. 31, 2007, pp. 909-917. https://doi.org/10.1016/j.proci.2006.07.248
- Kurdyumov, V. and Matalon, M., "Dynamics of an edge flame in a mixing layer", Combust. Flame. Vol. 139, 2004, pp. 329-339. https://doi.org/10.1016/j.combustflame.2004.09.005
- Kurdyumov, V. and Matalon, M., "Radiation losses as a driving mechanism for flame oscillations", Proc. Combust. Inst. Vol. 29, 2002, pp. 45-52.
- Kurdyumov, V. and Matalon, M., "The porousplug burner:Flame stabilization, onset of oscillation, and restabilization", Proc. Combust. Flame. Vol. 153, 2008, pp. 105-118.
- Lawton, J., Weinberg, F. J., "Electrical Aspects of Combustion", Clarendon Press. Oxford. Vol. 14, 1970, pp. 283-284.
- Lee, S. M., Cha, M. S., Park, S. H., Chung, S. H., "Effect of Electric Fields on the Liftoff of Nonpremixed Turbulent Jet Flames", IEEE Trans. Plasma Sci. Vol. 33, 2005, pp. 1703-1709. https://doi.org/10.1109/TPS.2005.856414
- Won, S. H., Park, C. S., Cha, M. S., Chung, S. H., "Effect of electric fields on reattachment and propagation speed of tribrachial flames in laminar coflow jets", Proc. Combust. Inst. Vol. 31, 2007, pp. 963-970.
- Won, S. H., Ryu, S. K., Kim, M. K., Cha, M. S., Chung, S. H., "Effect of electric fields on the propagation speed of tribrachial flames in coflow jets", Combust. Flame. Vol. 152, 2008, pp. 496-506. https://doi.org/10.1016/j.combustflame.2007.11.008
- Cetegen, B. M., Kasper, K. D., "Experiments on the oscillatory behavior of buoyant plumes of helium and helium-air mixture", Phys. Fluids, Vol. 8, 1996, pp. 2974-2984. https://doi.org/10.1063/1.869075
- Lee, B. J. Chung, S. H., "Stabilization of lifted tribrachial flames in a laminar nonpremixed jet" Combust. Flame. Vol. 109, 1997, pp. 163-172. https://doi.org/10.1016/S0010-2180(96)00145-9
- Park, J. S., Hwang, D. J., J. Park, Kim, J. S., Kim, S., Keel, S. I., Kim, T. K., Noh, S. S., "Edge flame instability in low-strain-rate counterflow diffusion flames", Combust. Flame. Vol. 146, 2006, pp. 612-619. https://doi.org/10.1016/j.combustflame.2006.06.009