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° 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.
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Abbreviations
- C :
-
Gas concentration, kmol/m3
- C avg :
-
Average gas concentration, kmol/m3
- C c :
-
Cunningham correction factor, -1
- D 1 :
-
Diameter of the chamber, m
- D 2 :
-
Diameter of the secondary air nozzle, m
- d p :
-
Particle diameter, m
- L :
-
Characteristic length of the volume flow, m
- N :
-
Number of measurement positions
- n :
-
Number of secondary air nozzles
- S :
-
Swirl number
- t :
-
Residence time, sec
- U :
-
Velocity, m/s
- U 1 :
-
Primary chamber gas velocity, m/s
- U 2 :
-
Secondary air nozzle velocity, m/s
- V :
-
Output voltage of manometer, V
- θ:
-
Injection angle of the secondary air nozzle, degree
- α:
-
Mixing performance parameter
- μ:
-
Fluid viscosity, kg/m s
- ρp :
-
Particle density, kg/m3
References
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.
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.
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.
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.
Shin, D., Ryu, C. K. and Choi, S., 1998, “Computational Fluid Dynamic Evaluation of Good Combustion Performance in Waste Incinerators,”Air and Waste Management Asso. J., Vol. 48, pp. 345–351.
Turns, S. R., 1996,An Introduction to Combustion, McGRAW-HILL 1st ed., pp. 499.
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.
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Shin, D., Park, S., Jeon, B. et al. 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. J Mech Sci Technol 20, 2284–2291 (2006). https://doi.org/10.1007/BF02916344
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DOI: https://doi.org/10.1007/BF02916344