有无中心锥圆排波瓣喷管引射器内流场模拟与比较

用数值模拟手段研究了中心锥增进圆排波瓣喷管引射器内热混合流场的影响 ,推导了非正交曲线坐标系下有无中心锥圆排波瓣喷管引射器内流场的基本方程 ,采用 SIMPLEC算法和一种完全压力修正方法 ,以物理平面速度分量作为求解变量 ,以逆变速度作为界面流速 ,在同位网格上求解了有中心锥波瓣喷管引射器内的流场控制方程 ,并与实验测量结果和无中心锥的数值计算结果进行了比较。结果表明 ,计算结果与测量值符合较好。有中心锥的低温等值线可以延伸至中心轴线 ,与在没有中心锥的情况下 ,混合管中心轴线处的温度始终保持为高温状态有很大的不同。从而找到了有中心锥的圆柱混合管热混合效率大于没有中心锥的根本原因

Numerical Simulation of Flow Field in Circularly Lobed Exhaust-Ejector Mixer with/without a Central Plug

The role of the central plug in promoting the thermal mixing between the primary and the secondary flows of the circularly lobed nozzle was assessed mainly by the numerical simulation.The fundamental equations were derived in the body fitted nonorthogonal coordinates from cylindrical coordinates for the circularly lobed exhaust ejector mixers with/without a plug in the center of the lobe.These equations were solved using SIMPLEC and a kind of complete pressure correction algorithm in the nonstaggered grids,with the velocity components in physical plane as solving variables and the contravariant velocity components as boundary velocities of the controlled volume.Better agreements have been observed between the numerical results and the experimental values.The numerical results show that there are great differences between the temperature contour in the outer section of the column mixer with the plug in which the low temperature contour lines can reach the center line of the mixer,and that in the outer section of column mixer without the plug in which the elevated temperature contour lines always lie in the central zone.This is the basic reason why the thermal mixing efficiency of the mixer with the plug is much more than that of the mixer without the plug.