Study Of Ultrasonic Propagation Charactoristics And Its Testing Equipment

The characteristics of ultrasonic sound velocity is a key factor affecting the measurement accuracy in the field of ultrasonic measurement. Such as ultrasonic flow detection technology plays an important role in the energy measurement, the accuracy of the ultrasonic flow detection is affected by the ultrasonic propagation medium and the temperature, pressure and other environmental conditions. For a long time, however, we also lack of adequate researches on the ultrasonic velocity changes with the fluid medium, temperature and pressure, and researches on the compensation method of ultrasonic flowmeter at different medium, temperature and pressure, which led to the accuracy of the ultrasonic flowmeter is difficult to improve,and greatly limits the development and application of ultrasonic flow detection technology. Therefore, it is necessary to study the characteristics of ultrasonic velocity in different media and different temperature and pressure, and then improve and refine the appropriate compensation method to improve the measurement accuracy of ultrasonic flow measurement technology. The main contents of this paper are:(1) Firstly, according to the research purposes, the scheme of the system is determined, including the design of the measuring device and the measurement scheme of the sound speed. The design of measuring device includes three parts of measuring container, gas and liquid pressure control mode and temperature control module. then the measuring device is built according to the design scheme. Sound velocity measurements using two frequency-driven phase measurement method.(2) The ultrasonic velocity measurement circuit is designed according to the sound speed measurement scheme, which includes the design of hardware and software system. The hardware system includes four parts of signal generation and phase measurement module, ultrasonic transducer signal drive module, ultrasonic receiver signal processing module, signal acquisition and display module. software design part mainly includes lower computer software design and host computer design.(3) Experimental study on ultrasonic velocity characteristics of air and water medium was carried out by using the measuring device and the measuring circuit,experiment is conducted firstly on the sealing experiment(including air sealability and liquid sealability), in the premise of good seal, the temperature- velocity characteristics experiments were conducted in the water medium under two conditions of zero pressure and 1MPa pressure, and the pressure-velocity characteristic experiment under two conditions of the temperature was 15°C and20°C. In the air medium, the temperature- velocity characteristics experiments were conducted under two conditions of zero pressure and 0.4MPa pressure, and the pressure- velocity characteristic experiment under two conditions of the temperature was 15°C and 17°C. The repeatability of the experimental data is good.(4) According to the measuring data of relationship of medium,temperature,pressure and velocity, a mathematical model of ultrasonic velocity relationship with temperature and pressure are summarized both air and water media, and analyzes the application of the model.