基于正交试验切线泵的优化设计

发布时间：2019-03-20 11:34

【摘要】：切线泵具有流量~扬程曲线比较平坦、工作可靠等性能优势被广泛应用于石油化工、航空航天、消防等领域,国内许多学者对切线泵的研究也从常规转速向高转速转移,使得切线泵具有更加广阔的应用范围和领域。本文以切线泵WG211-10为研究对象,首先在泵试验台上对模型泵进行外特性试验,记录试验数据并绘制外特性曲线图,观察曲线的变化情况,然后运用CFD技术对模型进行数值模拟,将模拟所得的结果和试验数据进行对比分析,以验证数值模拟策略的正确性。以此为基础研究切线泵内流场的变化情况和关键几何部件参数的变化对切线泵性能的影响;由于国内目前所生产的切线泵与国外先进水平在效率上有一定的差距,利用数值模拟和正交试验的方法,对切线泵WG211-10进行优化,以提高其效率;本文研究的主要内容如下:1、对模型泵WG211-10进行数值模拟,研究其内流场发现:观察速度场可以看出在叶轮叶片流道内存在大量的漩涡,这是导致切线泵效率低的主要原因之一。2、通过改变不同喉部直径研究喉部面积对切线泵性能的影响发现:喉部面积对切线泵的最大流量Q_max起决定性作用;喉部面积对切线泵的效率也有一定的影响,该泵型在喉部直径取10mm时有较高的效率。3、流量系数是设计切线泵的主要参数之一,为了保证泵在运行时既要有较高的效率,又不超过截止流量,流量系数的取值应在0.75~0.8之间取值。4、叶轮叶片和蜗壳之间的间隙对切线泵的性能有一定的影响,分别选取1.2mm、1.8mm、3mm的间隙,研究发现间隙对切线泵的效率影响比较大,间隙越小,效率越高,考虑到轴在运转过程中可能发生弯曲,间隙太小会使叶轮叶片和蜗壳相接触,影响泵的正常运行,综合考虑各方面因素间隙取2mm比较合适。5、综合分析切线泵叶轮结构和蜗壳的主要几何参数,选取叶轮外径D_2、叶片出口宽度b_2、叶片倾角θ、蜗壳喉部直径D_d为试验因素进行正交试验,得到的最优方案为:b_2=9mm、θ=10.5°、D_d=9.6mm、D_2=126mm;将最终方案进行样机制作,在泵试验台对样机进行试验,与原泵型的内流场和外特性曲线对比:在原泵型叶轮叶片之间的流道内存在着大量的漩涡,对该泵型优化后,发现在叶轮叶片之间流道内漩涡消失或者漩涡面积减小;优化泵样机在设计工况点的扬程为223m,比原泵型的扬程高2m,优化泵的效率为43.3%,比原泵型模拟效率提高了1.3%,轴功率为14.4k W,比原泵型轴功率低0.58k W,达到了优化设计的目的。
[Abstract]:Tangent pump is widely used in petrochemical, aerospace, fire protection and other fields because of its smooth flow-head curve and reliable operation. Many domestic scholars have also transferred the research of tangential pump from conventional speed to high speed, and so on, and it has been widely used in many fields such as petrochemical industry, aeronautics and aerospace, fire protection and so on. So that the tangent pump has a wider range of applications and fields. In this paper, the tangential pump WG211-10 is taken as the research object. Firstly, the external characteristic test of the model pump is carried out on the pump test-bed, the test data are recorded and the curves of the external characteristics are drawn, and the change of the curve is observed. Then the CFD technology is used to simulate the model, and the simulation results are compared with the experimental data to verify the correctness of the numerical simulation strategy. Based on this, the influence of the variation of the flow field in the tangential pump and the parameters of the key geometric components on the performance of the tangential pump is studied. Because there is a certain gap in efficiency between the tangential pump produced in China and the advanced level in foreign countries, the WG211-10 of tangential pump is optimized by numerical simulation and orthogonal test to improve its efficiency. The main contents of this paper are as follows: 1. The numerical simulation of the model pump WG211-10 is carried out and the internal flow field is studied. It is found that there are a large number of swirls in the impeller vane passage when the velocity field is observed. This is one of the main reasons leading to the low efficiency of tangential pump. 2, the influence of throat area on the performance of tangential pump is studied by changing the diameter of different larynx. It is found that the throat area plays a decisive role in the maximum flow rate Q_max of tangential pump; The throat area also has a certain effect on the efficiency of the tangential pump, which has a high efficiency when the throat diameter is 10mm. 3. The flow coefficient is one of the main parameters in the design of the tangential pump, in order to ensure that the pump has high efficiency in operation, 4. The clearance between impeller vane and volute has a certain effect on the performance of tangential pump, and the clearance of 1.2 mm, 1.8 mm, 3 mm, respectively, should be between 0.75 and 0.8, respectively, and the cut-off flow rate should not exceed the cut-off flow, and the value of flow coefficient should be between 0.75 and 0.8. 4. It is found that clearance has a greater effect on the efficiency of tangential pump, and the smaller the clearance, the higher the efficiency. Considering that the shaft may bend in the course of operation, too small clearance will contact the impeller vane and volute and affect the normal operation of the pump. It is more suitable to take 2mm for consideration of various factors. 5. The main geometric parameters of impeller structure and volute of tangent pump are comprehensively analyzed, and the external diameter of impeller, the width of blade outlet, the angle 胃 of blade, the external diameter of impeller, the width of blade outlet, and the angle 胃 of blade are selected. The orthogonal experiment was carried out on the throat diameter of volute. The optimum scheme was as follows: b ~ 2 ~ (2) ~ 9 mm, 胃 = 10.5 掳, D ~ (?) = 9.6 mm, D ~ (2) ~ (126) mm, and D ~ (2) 脳 10 ~ (- 1) mm, (P < 0.05). Compared with the inner flow field and external characteristic curve of the original pump type, the final scheme was manufactured and tested on the pump test bed. There are a lot of whirlpool in the channel between the impeller blades of the original pump type, and after the optimization of the pump type, the flow field and the external characteristic curve of the original pump type are compared with those of the original pump type. It was found that the vortex disappeared or the vortex area decreased in the passage between the impeller blades. The head of the optimized pump is 223m, 2 m higher than that of the original pump, the efficiency of the optimized pump is 43.3%, the efficiency of the optimized pump is 1.3% higher than that of the original pump, the shaft power is 14.4kW, and the shaft power is 0.58kW lower than that of the original pump. The optimization design is achieved.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH38

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