Research Of Unsteady Internal Flow And Vibration Characteristics Of The High Pressure Circulating Pump

With the continuous development of society,pumps are increasingly developing in the direction of large flow and high head,which must require the pump to have good stability;unstable flow and vibration in the pump is an important factor affecting the pump performance stability.Therefore,the research on the unstable flow and vibration characteristics of the pump plays an important role in ensuring the stable and safe operation of the pump;this paper takes a centrifugal high-pressure circulating pump as the research object,and comprehensively uses fluid numerical calculation,Fluid-solid coupling,experimental testing,and signal processing technology have carried out research on unstable internal flow and vibration characteristics.The main contents are as follows:(1)Numerical study of unstable flow of the high pressure circulating pump.First of all,the internal flow field in high pressure circulating pump was used Pro/E software modeling,then meshing and verified the accuracy of the numerical simulation.Based on SST k-?model the three dimensional flow field of high pressure circulating pump in steady and unsteady state was calculated.In the steady state under different flow rate,we analyzed pressure and velocity distribution.The unsteady state based on the result of the steady state is calculated.In the unsteady calculation we monitored the guide blade,impeller and inlet and outlet of the pressure pulsation.Then the time domain waveform analysis and frequency domain analysis were used to analyze the internal pressure pulsation characteristics.Finally it is concluded that the dynamic static interference is the main reason for the pressure pulsation produced.(2)Analysis of free mode of impeller and unidirectional coupling of rotor system of high pressure circulating pump.The rotor system is an important part of the high pressure circulating pump,and its operation stability is related to the stability of the whole high pressure circulating pump.Firstly,the experimental test and numerical calculation of the impeller mode in free state were carried out,and the error of simulation was calculated.It was found that the error between simulation and experiment was less than 5%,and the validity of numerical calculation in rotor analysis was obtained.Then the rotor subsystem was modeled,and the deformation and stress of the rotor system were analyzed based on the unidirectional fluid-structure coupling.It was found that the maximum deformation was less than the clearance between the guide vane and the impeller,and the maximum stress was less than the yield limit of the material to ensure that it would not be damaged.Finally,the prestressed mode of the whole rotor system is calculated and its resonance characteristics are analyzed to ensure that the resonance damage will not occur during operation.(3)Testing pressure pulsation and vibration characteristic of high-pressure circulating pump.Firstly,the test rig of the high-pressure circulating pump was built,and then the pressure pulsation signals and vibration signals were collected at the inlet and outlet of the high-pressure circulating pump under different flow rates.The collected data were firstly analyzed in time domain and frequency domain.After considering the pressure pulsation and vibration signal are cyclostationary signal,the time domain and frequency domain analysis cycle stationary signal have limitations.So the simulation cyclostationary signal was constructed to verify fast spectral correlation algorithm in the processing of the effectiveness of cyclostationary signal,then use fast spectral correlation to analyze these two signals.Finally,the correlation between pressure pulsation and vibration signal is obtained based on the results of cyclostationary analysis.