| Vortex flowmeter is a kind instrument based on the Karman vortex street.Vortex flowmeter has many advantages and has been widely used.Karman vortex street comes from fluid vibration,so the vortex flowmeter is susceptible to vibration interference,which can reduce the accuracy of the vortex flowmeter.Generally,there is mechanical vibration on the industrial environment.In order to meet the needs of industrial production,a structure of double probe sensor is put forward,based on the characteristics of the pipe vibration.The main completed works are as followed:(1)Theoretical analysis of pipe vibration.Firstly,the source of pipe vibration is analyzed according to the actual industrial environment;the vibration type of the pipe is determined as the forced vibration under the periodic excitation.Then,by establishing and solving the differential equation of pipe vibration,the vibration characteristics and factors are analyzed.Finally,the reason of pipe resonance and the effect of flow-solid coupling on pipe vibration are analyzed.(2)Experiment of pipe vibration.The vibration of pipe is measured by three-axis accelerometer.The characteristics of pipe vibration is clarified.The influence degree of the natural frequency of the pipe,the inherent frequency of the gas column and the fluid-solid coupling on the pipeline vibration are experimentally analyzed,and the suggestions of considering the relevant factors are given according to the industrial environment.(3)Mechanical structure of the probe is designed.The hardware system is set up based on FCTVT430,and the software implementation is given.The anti-vibration performance of the sensitive material is compared,and the piezoelectric crystal with better performance is selected as the sensitive material.(4)The performance of the DN50 flowmeter is test.The flowmeter shows well under three experimental conditions including pure flow,pure vibration and vibration mixed flow,which can withstand vibration of 0.8g-20 Hz and higher frequency. |
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