Influence Of Structural Parameters Of Crossover On The Performance Of Centrifugal Pump

Because the volute-type multi-stage pump has the advantages of wide range of high efficiency,flat performance curve,low vibration and noise,less machining and easy assembly and maintenance,it is widely used in petrochemical,metallurgical manufacturing,mine drainage and civil high-level water supply and so on.In practical application,the hydraulic loss in the crossover is large,which seriously affects the performance of the centrifugal pump.In this paper,the 200SHL160×2 petrol-chemical pump is selected as the research object to further study the influence of the structural parameters of crossover on the performance and the internal flow of the centrifugal pump.The main work and achievements of this paper are as follows:1.In the process of studying the current situation of the volute-type multi-stage pump in the domestic and foreign,this paper emphatically analyzes the research progress of the crossover.Carry out the numerical simulation of the centrifugal pump,and emphatically analyze the characteristics of the flow in the crossover.The results show that the hydraulic loss of the crossover increases and the performance of the pump is deteriorated due to the increase in the flow rate.This trend is slow in small flow conditions and faster in large flow conditions.As the changes of flow channel area and the bends,the diffusion section and the transition section have secondary flow and vortex.2.Carry out the numerical simulation of each model obtained by matching the selected centrifugal pumps with four crossovers of different radial length.According to the results of numerical simulation,analyze the energy characteristics of pumps and the internal flow state of crossovers.The results show that the change of the radial length of crossover has little effect on the performance of the centrifugal pump under the condition of small flow.Under the design case and the large flow condition,with the decrease of the radial length of crossover,the more serious the hydraulic loss of crossover.Therefore,the head and efficiency of centrifugal pump are reduced and the maximum gap of efficiency is 3.4%.The change in radial length has little effect on the pressure distribution and has a greater effect on the velocity distribution inside crossover.3.Put forward the linear regulation which the crossover sectional area expands uniformly and the concave and convex regulations which the crossover sectional area expands non-uniformly.The centrifugal pump with the radial length of 420 mm was selected as the research object.Under different conditions,the numerical calculation of the centrifugal pump with three kinds of crossover is presented.Analyzes the internal and external characteristic of pumps and the internal flow field distribution of crossovers.Compared with other kinds of pump,the pump with crossover of concave type is the best under the design conditions with lift increased by 12.86 m and efficiency increased by 3.42%.The change of the section area of crossover has little influence on the pressure distribution,but has a great influence on the velocity distribution in the crossover.