Hydraulic Performance Optimization And Structure Reliability Research Of High Temperature Pump

High-temperature pumps as the key equipment for conveying high-temperature and high-pressure media,have problems such as low hydraulic performance,poor structural reliability and unstable rotor operation,which severely restrict the development of the industry.In present work,under the funding of the Jiangsu Province Policy Guidance Program Project Granted number（BZ2020078）,the response surface model combined with genetic algorithm was used to perform multi-objective optimization of the performance of high-temperature pumps.The structural strength of the pump was analyzed based on the heat-fluid-solid coupling method,The rotor dynamics theory was used to research its critical speed and unbalanced response,which provides a basis for the optimization design of high-temperature pumps and the study of structural reliability.The main research contents and results are as follows:（1）Taking hydraulic efficiency and required NPSHr as the optimization goals,the Plackett-Bunman test design method was used to screen out the variables that have significant influence on the optimization goals,which are the impeller inlet diameter D₁,the blade wrap angleφ,the blade inlet placement angleβ₁,the blade outlet Placement angleβ₂,the position of blade inlet edge l.The regression equation of fitting variables and objective function based on Box-Behnken test results,combined with head constraint conditions to establish a mathematical model,using NSGA-II algorithm for optimization,the hydraulic efficiency of the obtained optimization model is increased by 3.17%,and the NPSHr is decreased by1.76m.（2）The performance and internal flow of the high-temperature pump before and after optimization were studied by numerical simulation methods:it is found that the internal flow field of the model pump has been significantly improved after optimization.With the increase of flow rate,the periodicity of pressure pulsation is obvious.The peak value of pressure pulsation is greater than the design conditions under the partial working conditions.Under the design conditions,the pressure pulsation peak at the outlet of the impeller channel is reduced by 18.7%,the peak pressure pulsation at the entrance of the partition and the tongue was reduced by 13.6%and 12.8%.（3）Based on the thermal-fluid-structure interaction method,the structural reliability of the high-temperature pump was studied:it is found that the maximum equivalent stress of the rotor components was concentrated at the intersection of the blade and the front and rear cover,and the maximum deformation is at the outer edge of the impeller.The maximum equivalent stress of the pump body is concentrated at the connection between the bracket and the pump body,and the largest deformation is at the outlet of the volute.The structural strength of the pump was checked based on the Von-Mises criterion,and it was found that the structural components all met the strength requirements.（4）The dry and wet modal analysis of the rotor components of the high temperature pump were completed,and the influence of the guide bearing structure and the wear ring clearance parameters on the stability of the rotor is studied.It is found that the natural frequency of each order of the wet rotor is greater than that of the dry state,and the difference in the vibration of each order of the rotor in the dry and wet mode results in different changes in the natural frequency.After considering the support effect of wear ring clearance,the critical speed of the rotor is significantly increased,and the displacement amplitude of the unbalanced response is significantly reduced.Compared with the wear ring clearance parameters,the guide bearing structure has a greater influence on the critical speed and unbalanced response of the rotor.When the relative clearance ratio is reduced to 0.002,the support stiffness of the guide bearing is increased by 19.1%,the first-order critical speed is increased by 26.3%,the displacement amplitude is reduced by 31.4%,the operation stability of the high temperature pump has been improved.