Two-Sheet OH-PLIF法による乱流予混合火炎の火炎構造および局所消炎の検討

摘要

In this study, using two-sheet OH-PLIF technique, we have obtained instantaneous two-dimensional flame images to examine highly turbulent premixed combustion in a cyclone-jet combustor. Since OH plays an important role in the combustion reaction, it has been reported that the flame front can be determined for the discussion of flame extinction. Here, the circumferential flame length and probability of flame existing are evaluated at different turbulence intensity. From vertical and horizontal images, the local flame extinction is confirmed based on 3D flame structure. When the exit velocity (U_m) is increased, more cusps appear on the flame front. At φ_m=0.90, the circumferential flame length is monotonically larger. However, at φ_m=0.75, the flame length is decreased at U_m> 20 m/s. In this condition, the probability of flame existing is decreased. Thus, the reduction of flame length could be explained by the local extinction.%近年，先進国だけでなく発展途上国の急速な発展にrn伴い，世界中で膨大な化石資源が消費されている．そrnの影響で，大気汚染や地球温暖化といった環境問題がrn深刻化しており，実用燃焼器はクリーンで高効率であrnることが求められている．