带射流冲击的短扰流柱排内流场的实验研究

Flow Field Measurements Around a Row of Short Cylinders with Jet Impingement

用五孔针对带射流冲击的单排短扰流柱内的流场作了详细的测量 ,得到并分析了带射流冲击的短扰流柱排内的速度分布规律及流场内的漩涡分布。在实验中清楚地探测到流动在靠近扰流柱表面附近速度较大 ,在对称中心区域发现了一大片低速区 ,并有回流和漩涡产生。实验发现由于端壁效应和扰流柱表面的流动分离造成扰流柱排内有较强的漩涡流动 ,扰流柱根部有马蹄涡产生 ,扰流柱后尾迹区有湍流涡的发展 ,流道内侧向压力分布不均匀可形成通道涡。与无射流情况比较发现扰流柱表面分离点后移 。

Detailed experimental measurements of the flow fields around a row of short cylinders with jet impingement by using a five hole probe have been conducted.The three dimensional velocities and vortex distribution were demonstrated and studied.The experimental data show that the largest velocity was observed at the place very close to the cylinder surface,velocities decreased rapidly in lateral direction from the surface to the symmetric plane of the channel where low velocity flow was found together with reverse flow and vortex.Endwall effect and flow separation result in strong vortices in cylinder array.Interaction of cylinder and endwall boundary layer produces horseshoe vortex at the root of the cylinder.In the wakes turbulent vortices exist.The lateral variation of pressure leads to the producing of channel vortex.As compared with the flow field without jet impingement,the angular position of separation on the surfaces of cylinder moved downstream and the width of wake was reduced obviously.