탄화수소 연료의 희박연소에 있어서 화염면 확장과 화염의 안정성

Abstract

An experimental study of turbulent premixed jet flames in CH4/Air mixtures is carried out in the lean combustion limit. Flame images were obtained using schlieren photography and analyzed to give detailed information on flame stretch and the stability of the turbulent flames in lean combustible mixtures. Measurements included laminar burning velocities for positive values of flame stretch up to 8600s-1. Flame stretch was calculated from the digitized images for fuel equivalence ratios 0. 305 - 0. 372. Flame distortion increased as distance from the jet nozzle increases and radius of curvature decreases along the nozzle axis. Extinction points were marked for each condition. It was found that in lean gas mixtures the flame stretch is inversely proportional to the flame length. The flame was stable in lean mixture while the hydrodynamically induced stretch is less than 8600s-1. Within this limit the flame was relatively stable even the mixture is beyond the existing measurements of lean combustible limits.