A Study On The Infiuence Of The Impeller Blade Thickness Of Plastic Centrifugal Pump On Pump Performance Based On The Fluid-Structure Interaction

Plastic centrifugal pump is widely used in the transport of corrosive materials such as those in chemical industry and petroleum for its outstanding corrosion resistance,light weight and low price.However,with the wider utilization of the plastic centrifugal pump,the higher performance is also required.Blade thickness,an important structural parameter,plays a role in the performance of plastic centrifugal pump.Excessive blade thickness narrows the flow passage and increases the relative velocity of the fluid in the flow passage,increasing the hydraulic loss;while the decrease of blade thickness widens the flow passage and lowers the slip coefficient so as to improve the efficiency of the pump.Owing to the material characteristics of the plastic centrifugal pump,the decreasing thickness may result in the impeller deformation to be too large due to the insufficient strength,which can cause the pump cannot work normally.However,there is no rule for the value of thickness in existing researches,which brings inconvenience to the designer.Therefore,in order to explore how the blade thickness of the plastic centrifugal pump affects the pump performance,on the basis of the research,the blade inlet angle was determined to be 19°,the outlet angle to be 33°,and the warp angle of blade to be 122°.In this paper,based on the fluid-structure interaction,the effects of equal thickness changing blades,axial thickness changing blades and radial thickness changing blades on the performance of plastic centrifugal pumps are studied respectively.The specific research contents are as follows:(1)Hydraulic design.Based on the given design parameters,the velocity coefficient method was used to design the structural parameters of the plastic centrifugal pump and to render the model of flow passage components.(2)Make a performance study of the plastic centrifugal pump with equal thickness blade.Through rendering the 3D model and grid division of the fluid domain,and simulating the internal flow field with CFX,it was found that the efficiency of plastic centrifugal pump decreased with the increase of blade thickness,and the cavitation resistance of impeller decreased gradually.By studying the pump performance under different working conditions,it was found that the maximum efficiency point was offset to small flow.(3)Find the minimum blade thickness through finite element analysis method.Loading the fluid internal pressure on the impeller entity,continuously reducing the blade thickness and using the fluid-structure interaction to see the deformation amount of the blades with different blade thickness respectively.Finally,comprehensive consideration was given to determining that the blade with 4 mm thickness was the minimum blade thickness designed for equal thickness.(4)Make a study of the influence of radial blade thickness on the pump performance.Based on the analysis results of equal thickness,the blade inlet thickness is determined to be 4mm,and the method of uniform thickness increase is adopted to design the outlet thickness.It was found that the internal fluid flow was more stable than the equal thickness,and the axial vortex phenomenon of the internal flow would be alleviated.In addition,with the increase of blade outlet thickness,the efficiency of the impeller increases gradually,and the efficiency of variable thickness blade increased slightly compared with that of equi-thickness blade.(5)Make a study of the influence of axial blade thickness on pump performance.On the basis of the equi-thickness analysis results,under the premise of ensuring thickness of blade root,tip thickness was offset by 2°and 4° respectively.It was found that the efficiency was 1.16%and 1.82%respectively higher than that of the original leaf by calculation.Therefore,under the same conditions,the tip thickness of the blade can be appropriately reduced on the basis of ensuring the blade strength requirement,which is beneficial to improve the efficiency of the plastic centrifugal pump.(6)Make a study of the influence of axial blade thickness on pump performance.On the basis of the equi-thickness analysis results,under the premise of ensuring thickness of blade root,tip thickness was offset by 2°and 4° respectively.It was found that the efficiency was 1.16%and 1.82%respectively higher than that of the original leaf by calculation.Therefore,under the same conditions,the tip thickness of the blade can be appropriately reduced on the basis of ensuring the blade strength requirement,which is beneficial to improve the efficiency of the plastic centrifugal pump.(7)Do a fluid-structure interaction analysis.The fluid-structure interaction analysis was carried out on the blade with variable thickness,and the stress-strain diagram was checked to ensure that the impeller would not be damaged due to excessive deformation,so as to meet the working requirements of the pump.At the same time,pump performance test is carried out to further ensure the accuracy of software analysis.The main conclusions and innovations of this paper are as follows:(1)According to the given parameters,the hydraulic design of the plastic centrifugal pump is studied.Firstly,the effect of different impeller thickness on the performance of the pump is studied,and then the flow field simulation is carried out on the impeller of different thicknesses,next the rule how the impeller blade thickness affects the performance of the centrifugal pump is proposed,and finally the boundary condition of the force is found by one-way fluid-solid coupling analysis,so as to determine the minimum blade thickness.(2)Based on the aircraft wing NACA 64-215 AIRFOIL model,the curve equation of blade thickness is obtained,which is improved by 1.2%in the efficiency of the blade design.