층류 확산화염에서의 PAH 및 매연생성에 대한 압력의 영향

Abstract

The effects of pressure on PAH and soot formation process in diffusion flames have been experimentally studied. The co-flow burner was housed in a high pressure chamber with optical access. A serie s of ethylene, ethane and propane laminar diffusion flames were studies utilizing a laser light extiction and scattering method for the integrated soot volume fraction and a broad-band LIF technique for the PAH concentration. Increasing operating pressure the soot formation process is enhanced while the soot oxidation process is suppressed, and therefore, soot particles are emitted eventually from a tip of the flame. The pressure dependence of-the soot formation process is greater for earlier residence times, and it was insensitive to the fuel tested in this study(ethylene, ethane and propane). The maximum soot yield appears to be a determining factor for the pressure dependence of the soot formation process. The greater sensitivity was observed when soot yield was less. The PAH concentration increases with pressure, and the pressure dependence of the PAH formation process is greater than that of the soot formation process. The peak soot volume fraction and the peak PAH concentration increases as ∼Pn, where n values are 1.7-2.25 for the soot volume fraction and 2.5 for the PAH concentration. This result implies that the PAH formation and particle inception steps in soot formation are more sensitive to operating pressure than the subsequent surface growth process.