Research On The Hydraulic Characteristics Of Double Volute Centrifugal Pump

With the continuous development of China’s industry and agriculture,the application of centrifugal pumps in industry and agriculture has become more and more extensive.In the ordinary single volute centrifugal pump,because of the asymmetry of the single volute structure,and the centrifugal pump will deviate from the optimal design condition during operation.This will lead to the flow field inside the centrifugal pump is not evenly distributed,even produce severe vibration and harsh noise.In order to effectively balance the radial force generated by the centrifugal pump during use,reduce the internal pressure pulsation of the impeller,improve the reliability of the centrifugal pump operation,and prolong the service life of the centrifugal pump,the double volute centrifugal pump is gradually being widely used.In this paper,the ZHA235-250-400 double volute centrifugal pump is taken as the research object.The numerical simulation method is used to analyze the flow field characteristics of the impeller and the volute under different wrap angles.The external characteristic curve is drawn according to the numerical results.Then,the turbulent kinetic energy distribution in impeller and volute and the pressure fluctuation characteristics in the volute diaphragm area under the optimal wrap angle are further studied.Firstly,according to the design parameters of the research object,the double volute centrifugal pump and its three-dimensional model of full channel are drawn.Five improvement schemes are obtained by changing the wrap angle of the impeller.The numerical simulations were carried out under the conditions of 0.6Q,0.8Q,1.0Q,1.2Q,and 1.4Q(Q is the design flow rate)for the five improved schemes.According to the numerical results,the flow characteristics of the impeller rotating surface and the volute channel cross section were analyzed,and the corresponding external characteristic curves were obtained.At the same time,the unsteady calculation is carried out based on the above numerical simulation results,and the pressure fluctuation distribution in the inner flow passage of the volute under five improved schemes is further analyzed.Secondly,through the analysis of the above five improvement schemes,it is proved that the performance of double volute centrifugal pump is the best when the blade wrap angle is 135°,and all hydraulic performances meet the design requirements,the pressure fluctuation amplitude of each monitoring point is low,and the vibration of the pump body is not large.Finally,under the optimal wrap angle,the turbulent kinetic energy distribution in impeller and volute and the pressure fluctuation characteristics in the volute diaphragm area are analyzed.From the turbulent kinetic energy distribution diagram of the impeller transverse section and volute section,it can be seen that the flow inside the impeller is the most uniform and the turbulent kinetic energy is the smallest at the design condition.From the pressure fluctuation characteristic diagram of the diaphragm area,it can be seen that the pressure fluctuation inside the diaphragm is greater than that outside.