The numerical study is performed to examine the structure of jet diffusion flame with/without a duct in the transitional flow regime, i.e., Re=1000-20000. The flame sheet model of infinite chemical reaction and unit Lewis number are assumed in the simulation. The mechanism of vortex growth is explained by using the streaklines visualized with marker particles, and the interrelation between vortical and thermal strctures is clarified for two cases with/without a duct. The presence of a duct leads to suppression of vortex growth in methane jet and therefore the flame spreading is significantly reduced.
Numerical flow visualization
Jet diffusion flame
Transitional flow
Flow and flame interaction