Application Of PIV Technique For Water Flow In Water Cushion Pool

With the speedy development of computer and image processing techniques, PIV (Particle Image Velocimetry) have developed correspondingly. As a tool of whole field, unintrusive and instantaneous measurement, PIV has been used widely in parameter measurement of liquid and multiphase and has good measurement precision. Some project applications and advantages of measurement technique of PIV are reviewed briefly, development tendency of PIV are summarized in this paper.Based on vast literatures related to flow visualization techniques, digital image processing techniques, high speed hydraulics, hydromechanics, author designed a set of test-bed of model, system of water circulation and lamp-house. The model is water cushion pool. There are two cases of 75 and 60 in the experiment. Sphericity electromagnetism valve and trail strobe are separately employed for adjusting entering flux and water deep of pool. PIV and PTV are employed to measure velocity field of model in the two casesof 75 and 60 and flow state image house are set correspondingly. At the same time, contour stream line, vortex, kinetic energy which are computed are important to investigate complex flow and turbulent flow. Air is entrained as water jetting into water cushion pool, the gas-liquid two phase flows field are formed. The every phase velocity field are measured by using PIV and PTV (Particle Tracking Velocimetry) method in the course of jet angle 75and60 in gas-liquid flows of water cushion pool. Image house of two phase flows are set up. PIV measures Vector fields of continuous phase (current field) by measuring tracking particle which traces current field. PTV measures disperse phase (bubble) velocity, this technique realizes simultaneity measurement of two phases. Before measuring velocity, separation technique of two phases was employed to realize the result of separation. At the same time, characteristic parameters such as particle diameter, concentration of bubble are provided in this paper.CFX software is used to simulate flow fields of water cushion pool. Contour stream line, vortex and kinetic energy in water cushion pool are found and offered as visualization form. The results of numerical simulation and PIV are analyzed and compared in this paper. The difference of two methods is relatively small and data of velocity accord preferably, the least absolute error is about 0.001m/s and the least relative error is 0. 49% in no boundary position, absolute error is big in the boundary positions which arouse measurement error. The results of PIV measurement are applied to pave good basement for setting model of numerical simulation and offer reliable data for numerical simulation.