| Plastic centrifugal pump is suitable for most corrosive environments such as acid,alkali and salt,and is widely used in the transportation of corrosive materials in chemical and petroleum industries.In the hydraulic design of the plastic centrifugal pump impeller,the experience of the blade profile design is very important,and it is difficult to determine which type of blade profile can make the plastic centrifugal pump have high quality performance.At present,for different blade profiles,domestic and foreign scholars have not put forward unified conclusions on blade profile’ s selection,and not found someone to analysis blade profiles with fluid-structure intersection.In order to study the influence of blade profiles of plastic centrifugal pump on pump performance,the main contents and characteristics of this thesis are as follows:(1)According to the parameters of plastic centrifugal pump,the impeller blade profile is designed and the two-dimensional model of impeller is drawn by single arc method,double arc method,logarithmic spiral method and B-spline curve method respectively.(2)According to the two-dimensional model of the plastic centrifugal pump impeller,three-dimensional modeling,meshing and internal flow field simulation under the design condition of several kinds of blade profile are carried out respectively.After post-processing analysis,it is concluded that the impeller drawn by the double arc method and the logarithmic spiral method are better than the B-spline curve method and the single-arc method from pressure and velocity cloud,and the impeller drawn by the logarithmic spiral method is superior to the other three blade profile drawing methods from the NPSH and the hydraulic efficiency.The internal flow field analysis of the impeller of several types of blade profiles provides a theoretical basis for the selection of impeller blade profile when hydraulic designing of plastic centrifugal pump.(3)The fluid-solid intersection analysis of the impellers of different profiles is carried out to compare the equivalent stress and deformation of different impellers under the same working conditions.The analysis shows that the impeller deformation of the four profiles is B-spline curve method>single arc method>double arc method>logarithmic spiral method,equivalent stress is B-spline curve method>double arc method>Single arc method>logarithmic spiral method.Among the four profiles,the equivalent stress and deformation of the logarithmic spiral are the smallest,so the impeller damage is minimal,which confirms the optimal conclusion of the logarithmic spiral when the internal flow field is analyzed.This paper has a guiding significance for the selection of plastic centrifugal pump impellers.(4)According to the results of simulation analysis,the logarithmic spiral method is determined to be optimal.The multi-objective function optimization model is established with the minimum power loss and the minimum NPSH of the plastic centrifugal pump.The inlet and outlet diameters of the plastic centrifugal pump impeller and the inlet and outlet angles of the blade are used as design the variables.Compare with the previous results,the hydraulic efficiency increased by 1.68%,which indicates that the impeller structure has been improved.(5)According to the three-dimensional model of different blade profiles,3D printing technology is used to print out the impeller physical model.The performance experiments of impellers designed by different profiles are carried out,then the experimental results are compared with the simulation results,which show that the logarithmic spiral method is the best in four types of profiles,and the single arc method is the worst,which verifies the correctness of the simulation results.On the basis of previous studies,this paper studies the effect of several blade profiles on the impeller performance of plastic centrifugal pump based on the simulation of flow field,fluid-structure intersection simulation,parameter optimization and experimental verification in plastic centrifugal pump.Compared with other research on blade profile,the main innovations of this paper are as follows:(1)By combining theoretical research,numerical simulation and experimental verification,the performance of impeller drawn by the methods of single arc,double arc,logarithmic spiral and B-spline curve is studied,and the logarithmic spiral method is obtained as the best method.(2)Based on the unidirectional fluid-solid interaction,the influence of different profiles on the structure of the plastic centrifugal pump impeller is studied,and the logarithmic spiral has the least influence on the impeller structure.(3)On the basis of the optimal blade profile,the blade profile is optimized by using the minimum power loss and the minimum NPSH as the objective function to determine a high quality impeller model. |
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