On the sensitivity of soot and thermal radiation simulation results to the adopted PDF for temperature underhighly sooting combustion conditions

The impact of the turbulent temperature fluctuations on soot processes and consequently on radiation heat transfer in a small furnace is investigated. A simplified approach based on presumed PDFs for temperature is adopted. Of interest here is the sensitivity of the simulation results to the shape of the used PDF. To cover a wide spectrum of turbulence possibilities two widely varying PDFs are adopted. One is a simple two-deltas function and the other is a beta function. Results show that (as compared with the case when the beta PDF is used) more soot is generated in the furnace, hence more heat is radiated to the furnace walls, when the two-deltas PDF is employed. However, regarding thermal radiation results, under the relatively high sooting conditions of the present furnace, the difference between the two cases is found to be insignificant.