Investigation of Droplet Combustion with Nongray Gas Radiation Effects

Abstract

Single droplet combustion processes including heating, evaporation, burning, soot formation and flame radiation were theoretically investigated by adopting nongray gas radiation model for the radiative transfer equation (RTE). n-Heptane was chosen as a fuel in the numerical calculation and the results were compared with the experimental data available in the literature. The discrete ordinate method (DOM) was employed to solve the radiative transfer equation and the weighted sum of gray gases model (WSGGM) was applied to account for nongray gas radiation effect by CO₂ and H₂O while soot was assumed gray. Therefore, very detailed effects by nongray gases could be figured out in the results. The results have shown that the total burning time increases due to a decrease in total heat flux with the nongrey gas model. It is also found that for the nongray case the radiative loss to external environment is higher, thereby reducing the maximum gas temperature and the flame thickness. Consequently, a better agreement with experimental data could be obtained by using nongray gas model.

Keywords:

• Single Droplet Combustion
• Radiative Heat Transfer
• Nongray Radiation
• Discrete Ordinate Method (DOM)
• Weighted Sum of Gray Gases Model (WSGGM)

Notes

*Corresponding Author: Prof. Seung Wook Baek, Department of Aerospace Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusung-dong, Yusung-ku, Taejon 305-701, Korea, Tel: [phone], FAX: [phone]. E-Mail: [email protected]