Extinction of the counterflow diffusion flame of blended fuels

摘要

For applications of the high-temperature air combustion technology (HiCOT) to waste incinerators, diffusion flame of blended fuel gases and high-temperature air in the stretch flow field were investigated. In this study, extinction limits of the counterflow diffusion flame for CH{sub}4-C{sub}3H{sub}8 blended fuel gases were obtained experimentally and numerically, varying the mixture fraction, fuel concentration and air temperature. Since the flame is unable to stabilize at small stretch rates due to the natural convection caused by buoyancy under normal gravity condition, the experiments were performed under microgravity condition. As increasing C{sub}3H{sub}8 percent of blended fuel gases and air temperature, extinction limits were extended. As increasing air temperature, the extinction limits at low stretch rates were not extended as much as that at high stretch rates. This reason is that, with increase of air temperature, the effect of radiation heat loss also becomes large at low stretch rates.