Flow Characteristics Analysis Of Guide Vane Multistage Centrifugal Pump And Guide Vane Structure Optimization

As the state pays more and more attention to energy conservation and emission reduction,the efficiency of multistage centrifugal pumps still has room for improvement.The guide vane is one of the main flow passage components in the multistage pump.So the performance of the guide vane largely affects the performance of the multistage pump.In this paper,the influence of guide vane structural parameters on pump performance is investigated by numerical simulation and MATLAB optimization.The main contents of this paper are as follows:(1)The first two stages of a multi-stage centrifugal pump were selected as the research object.The software PRO/E is choosen to conduct three-dimensional modeling of the inlet and outlet,impeller and guide vane respectively.Steady numerical simulation of the two-stage centrifugal pump is carried out through ANSYS.The simulation results show that the loss in the guide vane mainly occurs in the convex surface of the front guide vane,the circulation area and the convex surface of the return guide vane.The loss forms mainly include whirlpools,collisions and circulation.(2)Baesd on numerical simulation method,the effect of the parameter on the performance is simulated by changing one parameter and stabilizing other structural parameters of the return guide vane.The result shows that increasing of the inlet diameter of the return guide vane is beneficial to reduce the loss of the circulation under the premise of ensuring the right matching of the front and return guide,and thus the hydraulic performance of the pump is improved.Then the relationship between the radius of the guide vane and the wrap angle is derived based on the governing equation of the return blade angle and the MATLAB numerical calculation.Based on this relationship,three types of return guide vanes with different wrap angles were designed for numerical simulation.It is found that enlarging the wrap angle is beneficial to restrain the formation of the vortex in the convex surface of the return blade,and the bigger wrap angle,the more improvement of the hydraulic performance of the pump without considering the roughness.(3)The influence of the circumferential arrangement of the return guide vanes on the performance of the guide vane was qualitatively discussed.The results show that proper circumferential arrangement is beneficial to guide the fluid entering the return guide vane flow path in a more uniform way and then reducing the losses.Then the influence of axial distance between the outlet of return guide vane and the inlet of the next impeller on the pump performance is studied.The results show that in the vicinity of the design conditions,the larger axial distance is beneficial to improve the inlet flow condition of the next impeller,but the advantage decreases obviously with the flow rate.(4)On the basis of maintaining the original head and good cavitation performance,the impeller and the guide vanes are considered as a whole and then the MTALAB genetic algorithm toolbox is used to optimize it under multi-operating conditions.The optimization results are verified by the Anderson's area ratio principle.The results show that the optimized results are in the high efficient area compared with the original.