Effect of Swirling Flow by Normal Injection of Secondary Air on the Gas Residence Time and Mixing Characteristics in a Lab-Scale Cold Model Combustor

  • Shin, D. (School of Mechanical & Automotive Engineering, Kookmin University) ;
  • Park, S. (Department of Mechanical Engineering Yonsei University) ;
  • Jeon, B. (Department of Clean Engineering Yonsei University) ;
  • Yu, T. (Industry-Facility Team, Korea Institute of Industrial Technology) ;
  • Hwang, J. (Department of Mechanical Engineering Yonsei University)
  • Published : 2006.12.01

Abstract

The present study investigates gas residence time and mixing characteristics for various swirl numbers generated by injection of secondary air into a lab-scale cylindrical combustor. Fine dust particles and butane gas were injected into the test chamber to study the gas residence time and mixing characteristics, respectively. The mixing characteristics were evaluated by standard deviation value of trace gas concentration at different measurement points. The measurement points were located 25 mm above the secondary air injection position. The trace gas concentration was detected by a gas analyzer. The gas residence time was estimated by measuring the temporal pressure difference across a filter media where the particles were captured. The swirl number of 20 for secondary air injection angle of 5$^{\circ}$ gave the best condition: long gas residence time and good mixing performance. Numerical calculations were also carried out to study the physical meanings of the experimental results, which showed good agreement with numerical results.

Keywords

References

  1. Coghe, A., Solero, G. and Scribano, G., 2004, 'Recirculation Phenomena in a Natural Gas Swirl Combustor,' Experimental Thermal and Fluid Science, Vol. 28, pp. 709-714 https://doi.org/10.1016/j.expthermflusci.2003.12.007
  2. Huang, R. F. and Tsai, F. C., 2004, 'Flow and Mixing Characteristics of Swirling Wakes in Blockage-effect Regime,' J. of Wind Engineering and Industrial Aerodynamics, Vol. 92, pp. 199-214 https://doi.org/10.1016/j.jweia.2003.11.003
  3. Lans, R. P., Glarborg, P., Dam-Johansen, K. and Larsen, P. S., 1997, 'Residence Time Distributions in a Cold, Confined Swirl Flow,' Chemical Engineering Science, Vol. 52, pp. 2743-2756 https://doi.org/10.1016/S0009-2509(97)00086-9
  4. Nasserzadeh, V., Swithenbank, J., Scott, D. and Jones, B., 1991, 'Design Optimization of a Large Municipal Solid Waste Incinerator,' Waste Management, Vol. 11, pp.249-261 https://doi.org/10.1016/0956-053X(91)90072-D
  5. Shin, D., Ryu, C. K. and Choi, S., 1998, 'Com?putational Fluid Dynamic Evaluation of Good Combustion Performance in Waste Incinerators,' Air and Waste Management Asso. J., Vol. 48, pp. 345-351 https://doi.org/10.1080/10473289.1998.10464046
  6. Turns, S. R., 1996, An Introduction to Combustion, McGRAW-HILL 1st ed., pp.499
  7. Zhengqi, L., Rui, S., Lizhe, C., Zhixin, W., Shaohua, W. and Yukun, Q., 2002, 'Effect of Primary Air Flow Types on Particle Distributions in the Near Swirl Burner Region,' Fuel, Vol. 81, pp. 829-835 https://doi.org/10.1016/S0016-2361(01)00179-X