Study On Doppler Flow Measurement Of Large Diameter Slurry Circulating Pump By Ultrasound

In order to protect the environment and save energy and reduce emissions,desulfurization treatment of emissions is needed in production of thermal power plant.Limestone gypsum wet desulfurization is a commonly used desulfurization method.The energy consumption of slurry circulating pump in the system accounts for a large proportion.Therefore,the purpose of energy saving is to improve the efficiency of slurry circulating pump.As the fluid in the slurry circulating pump pipeline is chemically acidic and has a certain solid content,with the increase of service time,the blades in the slurry circulating pump will be damaged to varying degrees,which will lead to the decrease of pump efficiency and the increase of energy consumption.Therefore,this paper designs a flow measurement system based on ultrasound to measure the flow rate of slurry circulating pump pipeline,which provides a basis for the judgment of pump efficiency.Aiming at the problem of flow measurement in slurry circulating pump pipeline,taking the Doppler ultrasonic flow measurement system as the main research object,the theoretical research on fluid characteristics analysis,ultrasonic transmission and attenuation characteristics analysis in pipeline was carried out.The design of ultrasonic sensor,hardware circuit,software program,man-machine interface and wireless communication module were carried out.Work.According to the velocity distribution of the fluid in the pipeline and the related data of the ultrasonic sensor,the acoustic sensitive material,the acoustic wedge material,the transmitting frequency,the installation mode and the driving circuit of the ultrasonic sensor are calculated and determined,and the Doppler measurement method is optimized according to the acoustic wedge material and the transmission characteristics of the ultrasonic.According to the analysis of ultrasonic signal characteristics and the selection of common spectrum thinning methods,Zoom-FFT is chosen as the method of system spectrum analysis.According to the measurement principle and application occasion,the hardware circuit chooses suitable electronic components and integrated circuits,designs and tests various hardware circuit modules,such as transmitting signal generation,transmitting signal power amplification,signal transmitting module,echo reception,pre-amplification,frequency selective filtering,signal mixing,mixing signal filtering and AD sampling module.In the software part,according to the hardware circuit design and system measurement principle,the program is written for different programmable modules,such as DDS,FLASH storage,AD acquisition and the realization of complex modulation transformation.The complete measurement system is composed of the hardware part.Finally,the laboratory test is carried out with the developed prototype,and the experimental results are analyzed.The test results show that the measurement system designed in this paper works well and provides effective flow data for the efficiency evaluation of slurry circulating pump.