Analysis Of Multistage Centrifugal Pump Efficiency Research And Reliability Of Rotor

Multistage centrifugal pump is widely used in urban water supply?oil chemical industry and other industries of national economy because its high head.Multistage centrifugal pump has a complex structure, the multistage centrifugal pump based on the traditional design method, its actual work performance often can not meet the the corresponding models' national standard requirements.On the other hand, multistage centrifugal pump with high speed and its impellers are added in the series connection can meet the needs of high head. In the process of operation,the interaction between the internal flow field in the pump and the rotor easily leads to the fatigue rupture of the rotor. Therefore, simulating the full internal flow field of the multistage centrifugal pump and studying the rotor reliability under the unidirectional fluid-structure interaction are meaningful.This paper analyzed the internal flow field of the multistage centrifugal pump named D46-50X4, put forward improvement suggestion,the optimized rotor's modal analysis is also researched for the possibility of resonance during the operation process.First of all,the multistage centrifugal pump hydraulic design and simulation are completed. According to the design requirements of the multistage centrifugal pump named D46-50X4 do a hydraulic design, to completes its fluid domain in UG 8.0 and use the ANSYS CFX software to simulate the flow field, find out its design defects.In the next place, according to the defects of the existing model multistage pump,put forward two kinds of different improvement schemes: 1) Don't change pump overall design scheme of original, only add non-smooth drag reduction in blade working surface structure; 2) Make a new hydraulic design of the main flow area in multistage centrifugal pump impeller and guide vane.The verification of the two kinds of schemes were numerical simulated, and to determine the optimal improvement program, then compare the optimal solution with the original model multistage centrifugal pump the flow pattern in different conditions. The calculation results show that the head and efficiency are significantly improved by 43 m and 9.2% in the optimal solution. That indicate the optimal solution is up to the national standards, better optimization results have been achieved.Finally, modal analysis of the the optimized pump rotor is carried on.The results show that the rotor structure's first order critical speed is 12781r/min in the absense of prestressed,and this numerical change to 12455r/min when prestressed is loaded, both are grater than the rated speed 2980r/min,the rotor design meets the safety and reliability requirement.