Study On The Mechanism And Method Of Liquid Flow Measurement Based On High Frequency Ultrasound

The flow measurement is usually used in the industrial production and people’s life. Most of the existing flowmeters need to break the pipe to measure the flow, the fluid flow in the pipeline will be affected, and the replacement is difficult when the flowmeter is damaged. This paper studies the measurement and method of the liquid flow based on high frequency ultrasound, which can realize non-contact measurement outside the pipeline, and it is easy to use with multiple functions.Based on the detailed study of various flowmeters at home and abroad, the paper introduced the background and significance, and then analyzed the research status and development tendency of ultrasonic flowmeters, focusing on the principle and design of the time-difference ultrasonic flowmeter, the main contents include:Firstly, in this paper, the different basic principles and their advantages and disadvantages of several ultrasonic flowmeters are discussed, Two measurement methods of the time-difference ultrasonic flowmeter are also studied, which include the direct measurement of the time delay by the analog circuit and the calculation of the time delay by the cross-correlation method.Secondly, different wave fields in the pipeline of different frequencies ultrasound signals are studied. The propagation of different frequencies ultrasound in the water pipe is simulated using COMSOL software, and the sound pressure level distribution of difficult frequencies ultrasound is determined, which provides the guidance for the choice of the frequency of ultrasonic transducers.Besides, based on the introduction of the TDC-GP21 chip and the ultrasonic transducer, a time-difference ultrasonic flowmeter based on the TDC-GP21 is designed, the system structure is constructed, the circuit diagram is designed, the PCB layout is drawn and the programs of related modules are written.Finally, the experimental system of high frequency ultrasonic flowmeter is set up. The input and output characteristics of the transducer, the circuit and system are tested respectively.