In order to study the three-dimension flow characteristics of hydraulic coupling, the internal flow field of rectangular cavity-type hydraulic coupling was tested based on PTV (Particle Tracking Velocimetry) technology. Triple exposure technique on single frame was used to record three different lengths of particle motion trajectory. The internal flow direction of hydraulic coupling was judged accurately. Particle motion trajectory was extracted by edge detection algorithm, double threshold method was used to detect strong and weak edges. This method was proved efficient for detecting edges with sigle-pixel width and the displacements of particles were extracted directly, then the internal flow velocimetry was acquired, visualization of internal flow field and quantitative measurement were achieved. At the same time, the particle diameter can be estimated approximately.%为了研究液力偶合器内部流场的特性,该文基于粒子跟踪测速(PTV,Particle Tracking Velocimetry)技术对矩形腔型液力偶合器进行了内部流场试验测试,利片单帧3次曝光技术记录示踪粒子不同长度3段运动轨迹,准确判断了偶合器内部流场速度方向.运用边缘检测算法提取粒子运动轨迹,引入双阈值法检测图像强边缘点和弱边缘点,利用该方法可以有效地检测出图像的单像素边缘,直观地提取粒子运动位移大小,进而获得了液力偶合器内部流场速度,实现了其内部流场可视化与定量测量.同时,可以近似估计示踪粒子的粒径大小.
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