热边界条件对平板狭缝中火焰形状的影响

Effects on Thermal Boundary Conditions on Flame Shape in Narrow Channels

模拟了预混乙炔—空气火焰在平板狭缝中的传播,对不同热边界条件和点火条件下火焰形状的变化进行了研究。结果显示:在绝热边界条件下,当采用平面点火时,会形成并始终保持为郁金香状火焰;当采用火花点火时,则更倾向于形成蘑菇状火焰;在等温边界条件下,当采用平面点火时,火焰有一个由郁金香形状向蘑菇形状的转变过程,而采用火花点火时恰好相反。不同的转变过程说明,壁面散热对郁金香状火焰的形成具有双重作用。当壁面散热对燃烧影响较大时,会抑制郁金香状火焰的形成;而当壁面对流场流动影响较大时,火焰又会促进郁金香状火焰的形成。

The shape of unsteady premixed flames in narrow channel with adiabatic and isothermal wall is numerically investigated in the present study.It assumes that the flame chemistry is modeled by a one-step overall reaction which simulates the reaction of a stoichiometric acetylene-air mixture.The numerical results show that both ignition methods and thermal boundary conditions have effects on the formation of flame shape.A flame keeps single tulip shape in the whole process of propagation through the channel as ...