船舶推进器叶梢部流动PIV测试

利用2D-PIV（particle image velocimetry）技术在空泡水筒中对螺旋桨叶梢部流场进行了详细的测量。选用松花粉为示踪粒子,通过驱动轴轴编码器输出相位信号,经同步控制器控制CCD摄像及两激光器出光,解决了螺旋桨相位、激光器与CCD三者的同步控制与连续采集问题。轴向平面每一相位下均测量获得100幅瞬时速度矢量场,采用相位平均方法获得了同一相位下的平均速度场。比对了叶梢附近桨盘面前后流动的差异以及沿径向叶梢内外流场的不同,利用测试数据研究了梢涡、尾涡的结构。

Experiment on marine propeller blade tip flow with PIV

The 2D-PIV（Particle Image Velocimetey） technique was applied to measure the complex flow around a propeller blade tip in large cavitation tunnel.The pine pollen was chosen as seeding particles.An encoder mounted on the dynamometer shaft,feeds a special signal processor which sends a trigger signal to a special synchronizing device for each propeller angular position.The synchronizer provides a TTL trigger signal to a cross-correlation camera,to a double cavity Nd-Yag laser and to allow image acquisitions for each propeller angular position.100 instantaneous velocity fields were measured for each of 25 different blade phases,and ensemble averaged in order to find the character of flow field.Compared the fore flow field with the hind airscrew circle along axial.Compared the inner flow field with the outer airscrew circle along radial.Analysed the structure of tip vortex and trailing vortex.