冲击凹柱面靶板的流场结构实验

An experiment on flow structures of a round jet impinging on concave surfaces

关键词:  推进系统  喷射冲击  凹柱面+  流场显现  旋流结构

Key words:  Propulsion system  Jet impingement  Concave surface+  Flow visualization  Swirl structure

摘要:

采用烟线法研究了冲击凹柱面靶板的流场结构。研究中改变冲击雷诺数Re,冲击距-冲击孔直径比H/d以及冲击靶面相对曲率d/D等参数,利用数码摄像机拍摄流场结构随这些参数的变化规律。研究结果表明:上述参数均影响了冲击凹柱面靶板的流场结构,而且影响规律表现出较强的关联性。实验中,随冲击雷诺数Re的增加或冲击距-冲击孔直径比H/d的减小,在冲击滞止区域两侧形成的稳定旋流结构与冲击靶板分离处的圆心角增大,分离推迟;同时在实验中发现冲击靶板的曲率半径和冲击导管直径之间存在一定的匹配关系(d/D)使流体沿壁面运动的距离最长。

Abstract:

Smoke wire flow visualization was used to investigate the characters of a round jet impinging on concave surfaces at narrow space (the ratio of the jet impingement distance to the diameter of the jet hole H/d<1.0).Reynolds number Re,the ratio of the jet impingement distance to the diameter of the jet hole H/d and relative curvature d/D were changed in this experiment to study the rules of flow structures varying with these parameters.The results showed that all these parameters had great effect on the flow structures.The angles of the swirl structures separating from the surface became larger and the impingement fluid moving longer distance along the concave surface for the higher Re or lower H/d.In the experiment,there existed a proper range of d/D,which can result in a maximum distance for impingement fluid moving along the concave surface.