基于大涡模拟方法对一台燃用低热值气体燃料的发动机缸内湍流涡团与火焰相互作用过程开展了模拟,分析了缸内急燃期火焰传播过程中火焰前锋面上湍流涡核的分布特征,研究湍流涡团与火焰面的相互作用机理,并研究了涡对结构对火焰面传播的影响.结果表明:急燃期燃烧过程中,缸内背景湍流和火焰面相互作用,促使高强度涡核分布在火焰前锋面上,而涡核增大火焰面褶皱程度,火焰面面积增加,有助于更多高强度火核的产生;未燃区涡对的两个涡团相互逆向旋转导致火焰面受到局部的卷吸或者拉伸等作用,是火焰面出现明显皱褶的主要原因.
Large-eddy simulation on the in-cylinder turbulent flame-vortex interaction of lower heating value gases fueled spark ignited engine was carried out. Distribution of turbulent vortex core across the flame front and the interac- tion mechanism between flame front and turbulent vortex were analyzed. Effect of vortex-pair on flame front was stud- ied. Results show that the interaction between flame front and background turbulence produces much more high inten- sity vortices at the flame front. The vortex core is helpful to the increase of flame wrinkles. Flame wrinkles enlarge the flame area, producing much more turbulent vortices. The contra-rotation between the two vortices of vortex-pair in the unbumt area which leads to local entrainment and stretches to flame surface is considered to be the main reason for the generation of large scale flame wrinkles.