带有双层壁扩压器的波瓣喷管混合流场的数值计算

NUMERICAL COMPUTATION OF MIXING FLOW OF A LOBED EJECTOR WITH A DOUBLE-WALL DIFFUSER

采用三维贴体曲线坐标网格 ,边界网格加密且正交 ,在整个计算区域进行全场计算。为避免因波瓣造成的网格强烈的非正交引起解的发散 ,采用了 Chen和 Kim修正的 k-ε湍流模型及同位网格 SIMPLC计算方法 ,对带有双层壁扩压器的波瓣喷管混合流动进行了数值计算和分析。对波瓣及双层壁 ,采用大粘性的方法解决流固耦合。计算结果表明 :在双层壁间有外界冷气流被引射进入 ,形成了壁面的冷却气流 ;自波瓣出口截面沿流向产生的环流速度场 ,强化了主次流的掺混 ,速度分布渐趋均匀。计算结果与实验数据符合良好 ,二者在离开波瓣 5 2 mm的混合管内相对主流速度的最大误差为 2 1 .65 %。

The three dimensional body fitted grid is used. The grids near the boundaries are dense and orthogonal. The whole field of the domain is calculated. In order to avoid the divergence as the non orthogonality of the lobe, the Chen Kim modified k ε model of turbulence and the co located grid, SIMPLEC, are used in the numerical analysis of the mixing flow of the lobed ejector with a double wall diffuser by using the great viscosity for the lobe. The results show that the air is ejected into the double wall section to form the cooling flow, the annular like flow generated along from the lobe enhances the mixing of the primary and secondary flows and the velocity is well distributed. The maximum error between the numerical and the experimental data under the condition relative to the primary speed is about 21.65% at the position of 52mm from the lobe in the mixing section.