联焰板长度对驻涡燃烧室凹腔流动特性影响的数值模拟

Numerical Studies on Effect of Strut Axial Length on Cavity Flow Field in Trapped Vortex Combustor

开展了联焰板长度对驻涡燃烧室凹腔冷态流场特性影响的数值研究,结果表明:联焰板的流向长度存在两个临界值:Lc1=1mm和Lc2=9mm,当联焰板的流向长度小于等于临界长度Lc1时,主流会卷入凹腔中,凹腔中无法形成双涡结构;当联焰板的流向长度大于临界长度Lc1小于等于Lc2时,凹腔中可以形成双涡结构,但仍有部分主流会卷入凹腔中;当联焰板流向长度大于Lc2时,凹腔中可以形成双涡结构,主流几乎不会卷入凹腔中。

Numerical studies are carried out to investigate the effect of the strut axial length on the cold flow field of a trapped vortex combustor（TVC）.The results indicate that the flow field in the cavity of a TVC depends to a great extent which exceeds the general expectation upon the axial length of the strut.Two characteristic length Lc1=1mm and Lc2=9mm are achieved from detailed numerical simulations of the cold flow field.When the strut axial length is less than Lc1,agreat amount of mainstream is entrained into cavity and there exists only a single vortices in the cavity,whereas when the strut axial length is more than Lc1 and less than Lc2,the entrainment of the mainstream into the cavity seems to be eliminated and a dual-vortex dominant structure which consists of two vortices is observed in the cavity.And last,when the strut axial length exceeds Lc2,the flow in the cavity becomes independent of the axial length of the strut.As a result,changing axial length of the strut is regarded as a passive approach to control entrainment of mainstream into the cavity as well as interaction between the mainstream and cavity.