Flow Field Experimental Research On Upward Flow Hydraulic Separator Using PIV Technology

Upward flow hydraulic separators (UFHS) are one type of hydraulic separation equipment to work in accordance with the principle of difference in hindered settling velocity, it can be used for the classification of materials, can also be used for separating materials; which have not driving parts, have simple structure, and can deal with a large quantity of units, the only separation power is a constant upward flow. At coal separation, UFHS are unique epuipment which can content with separating coarse coal slurry particles, and easily incorporated into the process of coal preparation plant to link up with heavy medium and flotation system to reduce its load.Particle image velocimetry (PIV) technology can achieve movement status of the whole flow field by way of dispensing tracer particles to the flow field, using natural light or laser on the measured levels of exposure to form a light plane, obtaining two particle image with digital camera and calculating the image of the particle with cross-correlation method, including flow field parameters such as the speed of the quantitative distribution, vorticity field, streamline and Reynolds stress.In this paper, author measured various regions of the flow field in UFHS in virtue of advanced PIV technology, analysed single-phase circulating water character parameters at a rate of flow such as the distribution of vorticity field, turbulence intensity, Reynolds stresses, and one section of the distribution of speed; measured and analysed particles' movement status and the hierarchical rules to compare the speed of particle-phase and liquid-phase; study the upward flow rate in the role of the separation of particles. PIV measurement results are consistent with the classical theory of gravity separation and the actual situation observed, which visualization revealed the flow field movement status and particle movement status in UFHS , in order to offer reference for setting up mathematical model, carrying out sorting process simulation and practical application, and describes the feasibility of measurement using PIV technology on the UFHS.