轴流泵叶轮环形进口断面流速LDV测试研究

发布时间：2018-04-14 04:28

本文选题：轴流泵 + 叶轮进口　；参考：《扬州大学》2011年硕士论文

【摘要】：轴流泵叶轮进口流速分布的均匀程度反映进水流道设计的好坏,影响水泵的性能,掌握该断面流速分布规律为叶轮和进水流道优化设计提供依据,验证泵及泵装置数值模拟结果。本文采用LDV对长直管进水条件轴流泵叶轮进口流场进行三维测试,得到了不同工况下叶轮进口流速分布规律,主要完成了以下工作： 1、对试验轴流泵装置进行了外特性测试,得出了装置性能曲线,确定了小流量、设计流量、大流量等五种测试工况。2、利用校准盘对LDV进行调试和校准,保证LDV在空气中测试结果的准确性,对直管流速分布进行二维LDV测试,通过流量积分值与电磁流量计实测值比较,最大误差为-1.2%,精度比较高,验证了LDV通过视窗对圆管内流速分布测试的可行性与结果的准确性。3、对轴流泵叶轮进口距叶轮中心轴向距离分别为0.12、0.22、0.32倍叶轮直径处的径向测线进行了三维LDV测试。4、分析叶轮进口轴向速度分布结果,对边壁采用幂函数处理的速度分布进行流量积分计算,分析比较不同测点布置方案,改进了基于速度面积法泵站流量测试时测点布置及流量积分方法。由三维测试结果可以得出以下结论：1、0.5Qopt～0.7Qopt工况,轴向速度有回流、切向速度外壁侧不为0,方向与叶轮旋转方向一致,径向速度外壁侧速度方向与轮毂侧相反,水流流态较差；0.8Qopt～1.2Qopt工况时,轴向速度分布趋于均匀,切向速度除轮毂处基本为0,无旋转,径向速度轮毂侧与外壁侧方向一致,水流流态较好。2、基于速度面积法轴流泵叶轮环形进口断面流量测试时：测线位置宜选在距叶轮中心0.2D-0.3D范围内；测点位置,小于0.7Qopt工况时,流量积分计算误差较大,外壁面测点宜布置在0.95(R-R0)处；大于等于0.7Qopt工况时,靠近外壁面测点布置在0.9(R-R0)为宜；轮毂处测点在0.1(R-R0)～0.2(R-R0)为宜。
[Abstract]:The uniformity of inlet velocity distribution of axial flow pump impeller reflects the quality of inlet flow channel design, which affects the performance of the pump. Mastering the velocity distribution law of the section provides the basis for the optimal design of impeller and inlet passage.Verify the results of numerical simulation of pumps and pump devices.In this paper, the inlet flow field of axial flow pump impeller is measured by LDV, and the velocity distribution of impeller inlet under different working conditions is obtained. The main work is as follows:1. The external characteristic of the test axial flow pump device is tested, the performance curve of the device is obtained, and five test conditions, I. E. small flow rate, design flow rate and large flow rate, are determined. The LDV is debugged and calibrated by the calibration panel.To ensure the accuracy of LDV test results in air, the flow velocity distribution of straight tube is measured by two-dimensional LDV. The maximum error is -1.2 and the accuracy is high by comparing the flow integral value with the measured value of electromagnetic Flowmeter.The feasibility and accuracy of the velocity distribution test in a circular tube by LDV window are verified. The radial measurement line of axial distance from the inlet of the axial flow pump impeller to the center of the impeller is 0.12 ~ 0.22 ~ 0.32 times the diameter of the impeller, respectively. Three-dimensional LDV test is carried out for the axial distance between the impeller's inlet and the impeller's center.Analysis of the axial velocity distribution at the inlet of the impeller,This paper calculates the flow integral of the velocity distribution of the side wall treated by power function, analyzes and compares the different layout schemes of measuring points, and improves the method of measuring point arrangement and flow integral in the flow test of pumping station based on the velocity area method.From the three dimensional test results, the following conclusions can be drawn: the axial velocity has circumfluence, the tangential velocity is not 0, the direction is the same as the direction of impeller rotation, and the radial velocity is opposite to the hub side, and the radial velocity is opposite to the wheel hub side.The axial velocity distribution tends to be uniform under the poor water flow condition of 0.8Qoptl 1.2Qopt, the tangential velocity except the hub is basically 0, there is no rotation, and the radial velocity wheel side is the same as the outer wall side.The water flow pattern is better. 2. When measuring the flow rate of annular inlet section of axial flow pump impeller based on the velocity area method, the measuring line should be chosen within the 0.2D-0.3D range from the center of the impeller, and when the measuring point position is smaller than the 0.7Qopt condition, the error of flow integral calculation is large.It is suggested that the measuring points on the outer wall should be arranged at 0.95U R-R0; when the working conditions are greater than 0.7Qopt, the points near the outer wall should be arranged at 0.9V R-R0; and the measuring points at the hub should be at 0.1g R-R0 / 0.2nr0).
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH312

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