基于霍夫变换的液力变矩器泵轮内部流速提取

Extraction of internal flow velocity in pump of hydrodynamic torque converter based on Hough transform

液力变矩器传递能量的特性受其内部流场结构的影响,而内部流动特性决定其外部性能.为实现液力变矩器内部流动可视化,并在此基础上实现其内部流动速度的定量测量,提供详细且准确的流场试验测量结果,进一步完善对液力变矩器内部流动机理的研究.基于粒子图像测速(PIV)技术,对液力变矩器泵轮内部流场进行试验研究,在单次曝光下CCD相机采集泵轮径向切面流动图像,记录流场中示踪粒子的运动信息.通过图像处理技术识别流场中粒子运动轨迹的图像特征,以霍夫变换直线检测理论为指导,自动提取泵轮径向切面示踪粒子运动轨迹.由此实现了泵轮内部流动可视化,提高了流速矢量识别与量化计算效率.PIV试验测量结果能够揭示泵轮内部真实的物理流动现象和流场瞬态变化情况,为液力变矩器的性能预测及合理设计提供理论和实践参考依据.

The power transmission characteristics of hydrodynamic torque converter are highly influenced by internal flow structure. The external performance of hydrodynamic torque converter is determined by internal flow characteristics. It has important meanings to grasp the complex internal flow in hydrodynamic torque converter based on visualization of internal flow field and quantitative measurement of internal flow velocity. Research on internal flow mechanism of hydrodynamic torque converter can be improved through detailed and accurate experimental results. The internal flow field of the pump was measured based on particle image velocimetry （PIV） technology, and flow images on radial section of the pump were captured by CCD camera with single exposure, when motion information of tracer particles were recorded. Image features of tracer particle trajectory were identified by image processing techniques, and trajectories of tracer particles were extracted automatically based on Hough transform for line detection theory. By using the method above, flow visualization of the pump was achieved, and the efficiency of identification and quantification for flow velocity vector was improved. The results of PIV measurement can reveal the real physical flow phenomena and transient changes of internal flow field in the pump, and the theory and practice basis for performance prediction and rational design of hydrodynamic torque converter can be provided.