| Slurry circulating pump is an important part in the wet desulphurization system of thermal power plant,its working efficiency directly affects the desulphurization effect.But the grout circulating pump will appear corrosion wear after working for a period of time,resulting in the system desulfurization efficiency is reduced.Therefore,it is necessary to check and evaluate the working efficiency of the grout circulating pump regularly and timely,and the grout circulating pump outlet grout flow value is an important parameter to calculate the grout circulating pump efficiency,so it is of great significance to measure the grout pipeline flow to improve the desulfurization efficiency.According to the complex measuring environment of grout pipeline in thermal power plant,combined with the advantages of ultrasonic Doppler technology,the multi-phase flow ultrasonic Doppler detection technology can provide real-time and accurate grout circulating pump outlet flow information for thermal power plant.Due to the influence of the external environment in the process of ultrasonic wave propagation,it will cause interference to the echo receiving signal,thus affecting the accuracy of ultrasonic Doppler flow measurement.The factors such as temperature,sensor layout,multiphase fluid characteristics and ultrasonic attenuation characteristics are analyzed.The ambient temperature affects the ultrasonic propagation velocity,while the velocity,density and viscosity of multiphase flow are related to the turbulence intensity of pipeline fluid.In order to improve the stability,applicability and reliability of the measuring system,the key factors are compensated and corrected.Based on ultrasonic attenuation characteristics,this paper studies the relationship between ultrasonic working frequency and propagation attenuation by numerical simulation.The attenuation characteristics of ultrasonic signal at different transmitting frequency,different sensor installation Angle,different particle size,different slurry concentration and different gas-solid ratio of medium particle were analyzed by multi-physical field simulation,which provided reference for the selection of ultrasonic working frequency and sensor installation Angle.The different layout of ultrasonic sensor is analyzed.Therefore,in order to obtain real-time,accurate and effective multiphase fluid flow information,it is necessary to select appropriate ultrasonic sensor working frequency,layout and installation Angle according to different measuring environments.An indoor fluid circulation system was built according to the existing laboratory equipment,and the performance of the ultrasonic flow measurement system was tested.The flow measurement curve was obtained by changing the particle size and slurry concentration.The experimental results show that the relative error of slurry measurement is less than 12%. |
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