导管螺旋桨内流场的PIV测量

Investigation of internal flow field of ducted propeller using particle image velocimetry

内流场对于导管螺旋桨的设计和性能分析是至关重要的,利用随车式PIV在中国船舶科学研究中心拖曳水池进行了导管螺旋桨的内流场测量。使用标靶技术建立了物像对应关系,从而修正导管曲率和厚度产生的图象畸变。使用同步控制器实现螺旋桨相位、CCD摄像和激光器的精确同步控制。试验分别在三个不同进速系数J=1.2,1.0和0.8下进行。试验结果很好地反映了螺旋桨梢涡、毂部涡、以及螺旋桨上下表面脱落的旋向相反的尾涡,以及近导管内壁、桨毂壁面涡层等流动特征。试验表明,涡强都随着进速系数的减小而增加。与螺旋桨前流动相比,导管内螺旋桨后轴向速度沿径向分布的不均匀性明显增强。试验结果表明,对于导管厚度与曲率都空间变化的导管螺旋桨,应用PIV技术进行内流场测量在技术上是可行的。

Analysis of internal flow field is very important to the design and performance prediction of ducted propeller. The towing PIV is applied to measure the internal flow field of ducted propeller in a towing tank （150m× 7.0m × 4.5m） of CSSRC. A body-fitted target is used to calibrate the image distortion caused by the duct. The synchronizer controls laser and CCD to operate at preset angular position of propeller blade. The test is carried out at three advanced coefficients J = 1.2,1.0 and 0.8 respectively. The test results show clearly the flow characteristics of tip vortex, hub vortex, and trailing edge vortex （TEV） shedding from the upper and lower surface of propeller blade, and the vortices layer near boundary of the duet and hub. And it also reveals the variation trends of velocity field, vorticity distribution with advanced coefficients. The results from this test prove that the PIV technique is suitable to measure the internal flow field of ducted propeller.