The Safety Analysis And Optimization Design Of Multistage Centrifugal Pump

Centrifugal pump is a fluid machinery that relies on the centrifugal force produced by the rotation of the impeller to transmit the liquid.It is widely used in urban sewage,farmland irrigation,oil transportation,marine ships and chemical industry.The multistage centrifugal pump is two or more single stage centrifugal pumps in series to achieve the superposition of the head,so as to meet the needs of the high head of the centrifugal pump in the practical engineering.Besides the high efficiency and high head,all walks of life have also put forward more and higher standards for the safety and reliability of multistage centrifugal pumps with the progress of industrialization.Due to the complex structure and unsteady flow of internal fluid,the operation of multistage centrifugal pump is often complicated and accompanied by vibration,which seriously affects the safety and service life of multistage centrifugal pump.Aiming at the security and reliability of the multistage centrifugal pump,the strength,vibration characteristics and fatigue of the main components are analyzed by the finite element method in this paper,so as to ensure the safety performance of multistage centrifugal pump and by studying the characteristics of the pressure pulsation of the multistage centrifugal pump,the SVR agent model combined with the genetic algorithm is used to optimize the structure of the centrifugal pump to reduce the vibration.The main contents of this paper are the following points:(1)The safety performance of the multistage centrifugal pump analysis involves the calculation of solid mechanics and computational fluid mechanics,this paper analyzes the status of related research at home and abroad,combined with the actual situation of the subject,analyzed the flow components of multistage centrifugal pumps by using finite element method based on fluid-solid interaction,simulated the rest parts for safety performance according to different safety requirements,by using finite element analysis method based on structural statics method,structural dynamics method.(2)According to the technical standards of centrifugal pump and design manual,designed a multistage centrifugal pump that meet the technical requirements,and built a three-dimensional model;establish the finite element analysis of each model according to the characters of the main components of the multistage centrifugal pump.Analyzed the structural strength,vibration characteristics and fatigue of the components considering some important factors that affect the safety performance,and ensured the safety and reliability of multistage centrifugal pumps in the design stage.(3)Aiming at the complex stress distribution of impeller of multi-stage centrifugal pump's core components,5 schemes of blade head length and 5 different flow conditions are designed,and the influence of different schemes on blade stress distribution is analyzed and compared.When the length of the blade head is 9%of the total length,the stress distribution of the blade is relatively good,and the stress situation of the blade is very poor when it deviates from the design flow condition.(4)The internal fluid pressure pulsation of centrifugal pump was studied,and selected three key design variables of centrifugal pump pressure pulsation:tongue angle,throat area and the outer diameter of the impeller to establish the sample,used the Latin hypercube sampling method for sampling calculation,used support vector regression to calculate the regression and established the agent model.The genetic algorithm is used to optimize the calculation on the basis of the basis of the agent model.After optimization,the pressure of the tongue region is reduced by 8.4%.