Study On Hydraulic Model Performance Optimization Of Axial Flow Pump Based On Adjustable Guide Vanes

Axial flow pump has the characteristics of large flow and low lift,so it is widely used in farmland irrigation,cross-basin water transfer,flood control and drainage and so on.With the increasing application of axial flow pump,more and more experts and scholars pay more attention to the problem of improving the efficiency of axial flow pump.The impeller and the guide vane are the important parts of the axial flow pump,and how they connect directly determines the performance of the axial flow pump.At present,the impeller and the guide vane are basically limited to achieve a good matching in the design condition,while it's still a problem to be solved how to match in other conditions.In this paper,in order to improve the efficiency of the axial flow pump,it is proposed to adjust the angle of the impeller blade firstly,and then adjust the angle of the guide vane under various operating conditions.In this paper,the TurboGrid software was used to model and mesh the impeller and guide vane of axial flow pump.The water inlet and outlet pipes were modeled by the UG software and meshed by the ICEM CFD software.In the process of grid independent analysis,six kinds of axial flow pump models with different numbers of grids were selected to simulate and calculate.Compared with the calculated results,it was determined to use about 1.18 million grids for calculation Finally,different schemes were imported into the CFX software for calculation,and the simulation results were analyzed and compared.Focus on the adjustable impeller of axial flow pump,we analyze its regulation principle,calculate the external characteristic data at different impeller blade's angles of 0°?±3°?±6° under various operating conditions and simply analyze the influence of impeller angle on the hydraulic performance of axial flow pump.The key part of this article is the part of adjustment of the guide vane.Focus on the adjustable guide vane of axial flow pump,we analyze its regulation principle and propose a new guide vane adjustment mechanism.Based on the impeller blade's angles of 0°?±3°?±6°,we adjust the angle of the guide vane and calculate the angle which can make the efficiency max,and external characteristic data under various operating conditions.Compared with the angle adjustment of impeller blade,we analyze the influence of simultaneously adjusting the angle of the impeller and the guide vane on the hydraulic performance of axial flow pump.The calculation results show that when the flow rate changes,the angle of the guide vane which matches the impeller also changes.Under the small flow rate condition,the guide vane is adjusted to the negative angle,and under large flow,the guide vane is adjusted to the positive angle.When the flow rate is 306L/s,the maximum efficiency is 87.86%at the impeller blade's angle of-3° and the guide vane's angle of 0° which is increased by 1.46%compared with the efficiency without adjusting the impeller and the guide vane.It is 5.17%higher than the minimum efficiency without adjusting the guide vane and 3.02%higher than the minimum efficiency with adjust the impeller and the guide vane.When the flow rate is 374L/s,the maximum efficiency is 86.66%at the impeller blade's angle of 3° and the guide vane's angle of 3° which is increased by 3.74%compared with the efficiency without adjusting the impeller and the guide vane.It is 25.42%higher than the minimum efficiency without adjusting the guide vane and 16.11%higher than the minimum efficiency with adjust the impeller and the guide vane.The more it deviates from the optimal conditions,the more obvious the effect of adjusting the guide vane angle to improving the performance of the axial flow pump is.Therefore,in practical engineering,we should reasonably adjust the angle of impeller and guide vane according to the actual situation,so that they can connect effectively,the loss can be reduced and the performance of axial flow pump can be improved.