文氏管喉部直径对燃烧室流场结构影响的数值模拟

Numerical Simulation of Effects of Venturi Tube Throat Diameter on Flow Field of Combustor

为了研究文氏管几何结构对燃烧室流场特性的影响,对双级轴向旋流杯燃烧室流场进行了数值模拟.结果表明,文氏管喉部直径的变化使火焰筒回流区变化为3种典型形状,即"鼓状"、"鸭梨状"和"橄榄球状".其中"鸭梨状"回流区内排列有3个不同大小的涡,分别相当于主涡和次涡,通过改变火焰筒直径可以对主涡和次涡进行控制,可以产生符合设计要求的3涡结构;文氏管喉部直径变化会引起火焰筒内角涡的轴向移动,这种移动受回流区涡旋的影响,与火焰筒直径无关;随文氏管喉部直径的增大,回流区平均长度呈先增大后减小的趋势,而回流区宽度却逐渐减小.

To investigate the effects of venturi geometrical structure on flow field characteristics,numerical simulations were carried out in a combustor with a dual-stage axial swirl cup. The results show that the recirculation zone of combustor liner changes into three typical shapes,i.e.＂ellipsoid drum-shaped＂,＂pear-shaped＂and＂rugbyshaped＂,because of different throat diameter parameters of venturi tube. The＂pear-shaped＂recirculation zone consists of three different vortexes,which are equivalent to the main vortex and secondary vortex. By changing the diameter of the liner,the main vortex and secondary vertex can be controlled,so the triple vortex structure can be produced which meets the design requirements of the combustor. Different throat diameter parameters may cause the axial movement of corner vortexes in the combustor liner,which is affected by the vortexes in the central recirculation zone but has nothing to do with the diameter of the liner. With the increase of the throat diameter of venturi tube,the mean length of recirculation zone increases firstly and then decreases,while the width of recirculation zone decreases gradually.