曲り流路内乱流拡散火炎の統計的性質(熱工学,内燃機関,動力など)

抄録

Statistical characteristics of a non-premixed turbulent flame formed in a curved rectangular channel were investigated experimentally. Two types of flame-one formed in the center of the channel (Flame 1), and the other in the vicinity of the inner-wall (Flame 2) -were measured using a simultaneous measurement technique of velocity and temperature. In both flames, counter-gradient diffusion (CGD) emerged in heat transfer on the outer-wall side of the flames. Flame 2 showed a more distinct CGD than Flame 1, and was very elongated. Unlike Flame 1, Flame 2 did not accompany a strong "gradient-diffusion" heat transfer on the inner-wall side of the flame, and this may strengthen the CGD of Flame 2. Statistical analysis of a turbulent heat flux revealed the internal structure of the CGD, where high-temperature fluid parcels moving toward the outer-wall side were considerably slowed down (Flame 1), or returned with little diffusion (Flame 2). These are the essential features characterizing turbulent flames under a strong pressure-gradient.