Test And Investigate Of Flow Field In A Two-Phase Flow Water-Sediment Separation Device By PIV

’Vertical-component density flow water-sediment separation device’(shortly as ’separation device’) is a high efficient, simple structure, low cost and environment-friendly water and sediment separation device. Preliminary research on the ’separation device’ is mainly on the macro-test with the physical model, but the results have low accuracy and the theoretical analysis on the resultant lack of support of convincing data.PIV is an advanced optical transient flow field measurement technique, it have the advantage of no interference with the flow field, high accuracy and high test range. In this paper, the internal flow field of the’separation device’on two working conditions is tested by PIV, the test data is processed and analyzed by professional software, then derived the distributions of the flow’s velocity vector field and the isoline of velocity of flow which reflect the internal flow pattern of the’separation device’. The test results can provide reference and verification for the numerical simulation of the internal flow field of the ’separation device’, and provide convincing data to support the analysis of water and sediment separation mechanism. The following conclusions are getting by analysis of the PIV test results in this paper:(1) In the separation process of water and sediment, there exist a horizontal-component density flow between the gill slices of the’separation device’, which phenomena is that the sediment move down along with the upper surface of the gill slice and the water move up along with the undersurface oppositely. And a vertical-component density flow is formed in both sides of the vertical channel, which phenomena is that the sediment flow along with the sinking channel and the water flow along with the rising channel, both of the density flow accelerate the settlement of the sediment greatly.(2) Comparison of the test results in two working conditions indicates that there will be formed horizontal-component density flow and vertical-component density flow in different sediment concentration. The’separation device’ has well effect on separation of sediment and water in different sediment concentration.(3) Further confirmed the accuracy and reliability of the PIV test results by compare with the physical model test results, so the obtained analysis results is accurate and reliable.(4) According to the PIV test data, derive and verify the stability of the internal flow field of the ’separation device’. Due to the presence of gill slice, the sediment has been in a state of accelerate settlement in the process of sedimentation, therefore its settling velocity is much faster than the settling velocity in the case without gill slice.