Study On Performance Optimization Of Submersible Pump For Well Based On Meridian Surface Taguchi Test Design

As a common general machinery,well submersible pump is widely used in domestic water,urban drainage,sewage treatment,building water supply,mining,agricultural irrigation and other fields.Generally,the submersible pump works under water with high cost of installation and maintenance,and is immersed in water for a long time.Therefore,the hydraulic performance and stability of the submersible pump are required to be high.In this paper,with the support of NSFC project and Jiangsu Excellent Youth Fund project,the meridian plane of impeller and guide vane of well submersible pump is optimized based on the Taguchi test,which improves the hydraulic performance of the pump.At the same time,the unsteady numerical simulation of well submersible pump before and after optimization is carried out to explore the difference of pressure fluctuation characteristics before and after optimization.The main contents of this paper are summarized as follows:(1)This paper briefly reviews the development of well submersible pump,summarizes the optimization methods of impeller and guide vane,and introduces the research progress of transient characteristics of pump at home and abroad.(2)The 3D model of 250qj80 well submersible pump is built,and the grids are divided by single channel simulation and full flow field simulation respectively,and the applicability of the two methods is compared and analyzed.Although the accuracy of single channel numerical simulation is higher than that of full flow numerical simulation,the large reduction of its calculation period is more suitable for multi scheme pump performance optimization design.Therefore,in the part of optimization design,the single channel simulation method is used,and the full flow numerical simulation method is used in the unsteady calculation.(3)Based on the Taguchi test design method,the impeller and guide vane meridian plane are parametric decomposed,and the hydraulic performance is optimized by the effect analysis method and the signal-to-noise ratio analysis method.According to the statistical results,the level of factors and the performance indicators of the corresponding scheme are selected to determine the response priority of the factors.Based on the variance regression analysis,the linear equations of each factor and the performance indicators such as lift and efficiency are fitted.Finally,according to the optimization design goal,the optimization scheme with better performance is determined.(4)The impeller and guide vane scheme based on Taguchi test optimization design is compared with the original model before optimization.Through the comparison of external characteristics and the analysis of internal flow field,the corresponding internal flow field change law caused by the structure optimization is explored.After optimization,the front cover plate of the impeller expands outward,which leads to the full development of the liquid medium at the impeller inlet and weakens the original high-speed area at the impeller inlet.The early contraction design of the rear profile in the rear cover plate of the impeller makes it easy to accumulate the low-speed liquid at the flange to flow out in advance.These structural changes eventually improve the hydraulic performance of the impeller.However,the overall increase of the radial distance of the intersection line of the rear cover plate after the guide vane optimization makes the liquid flow through the middle of the guide vane passage not enough space to impact the front cover plate,so the area of the local high-speed area in the middle and rear of the guide vane passage is significantly reduced.In addition,the performance experiments of the initial model are carried out to verify the high accuracy of the numerical simulation method.(5)Several monitoring points are set up along the flow channel of submersible pump.The transient characteristics of pump are studied based on unsteady numerical simulation.The time-domain and frequency-domain characteristics of pressure fluctuation are mainly analyzed.The propagation law of low-frequency signal in pump is analyzed by CWT wavelet transform.The accuracy of the unsteady numerical simulation method is verified by the pressure fluctuation test.There are many pulsation sources and signal interaction phenomenon in the multi-stage submersible pump.The high frequency pulsation signal intensity in the pump is reduced to a certain extent after the meridian plane optimization.