| Measurement of ultrasonic velocity can reflect the flow,distance,temperature,gas concentration and other physical parameters,so the ultrasonic sound velocity measurement of the physical quantity of the detection of great significance.In the high temperature environment,conventional ultrasonic transducer with contact method to measure the speed of sound have the following two restrictions: 1,in high temperature environment(> 500 ℃),piezoelectric ceramic chip degeneration phenomenon;2,probe material in high temperature environment Under the different thermal expansion coefficient of the ultrasonic transducer failure.In this paper,the use of the probe as a sensor,developed a high temperature environment,ultrasonic velocity measurement system,you can isolate the impact of high temperature on the ultrasonic transducer,and can collect high temperature environment,ultrasonic echo calculation of the speed of sound.The wave rod used in the system is only a short distance to reduce the high temperature to a range suitable for the normal operation of the transducer without cooling.In this paper,based on the existing ultrasonic detection system,the whole ultrasonic sound velocity detection system in high temperature environment is developed and the design process of the hardware system in the detection system is described in the following.First of all,according to the theory of ultrasound select the direct probe excitation 1MHz excitation wave to detect the speed of sound,and then through simulation and measurement select the ceramic used as sensor material.By comparing the different types of ultrasonic probes and coupling agents,the straight probe is chosen as the transducer,and glycerol acts as a coupling agent.Secondly,the design of the hardware detection system.The transmitter system achievesthe generation of ultrasonic excitation signal,and the receiving system realizes the function of limiting,denoising,gaining and amplifying the echo signal,converting digital data,and storing data of USB2.0.Finally,through the software LabVIEW developed a USB2.0-based high-speed data acquisition,algorithm processing and control system.Through the experimental verification,the ultrasonic sound velocity detection system in the high temperature environment designed by the article can respond to the change of the external condition of the sensor in real time,and can measure the ultrasonic velocity of the ultrasonic wave up to 1600℃ for a long time.The detection system can be measured in a high temperature environment,or the temperature can be measured with the known temperature-sonic relationship. |
