Research On Ultrasonic Pressure Measurement Based On Changes Of Ultrasonic Velocity

Pressure is one of the most important parameters in running pipeline system.In order to ensure the devices working properly and safely,it is necessary to monitor the pressure.Most of conventional methods belong to the invasive method.The disadvantages are that anyone of those methods needs to be in a f'Lxed location and it may destroy the structure of the pipeline,as well as brings many inconvenience to the hydraulic system.So a novel method to measure the pressure noninvasively based on the ultrasonic is presented.With this method,pressure can be gotten by changes of the ultrasonic velocity;the major work completed is showed as follow:(1) Fixed on the scheme of ultrasonic hydraulic pressure measurementThe device was developed to measure the pressure based on the Elastic Longitudinal Wave by a detailed analysis of ultrasonic properties,the component of hydraulic oil and the propagation characteristics of ultrasonic in hydraulic system.An analysis of the main factors of the impact to ultrasonic pressure measurement technology has also been provided.(2) Researched on the method of measurement by the changes of ultrasonic velocityAnalyzed the existing methods of ultrasonic velocity measurement,and designed a new method for ultrasonic velocity measurement using a single-chip microcomputer to counter the pulse at a given time.The main uses of the single-chip microcomputer were its timer and counter.The change of ultrasonic velocity can be gotten by comparing the velocity measured to the velocity under the zero pressure.(3) Designed for the ultrasonic pressure measurement systemDetermined the ultrasonic transducer excitation signal based on the analysis of the equivalent circuit of the ultrasonic transducer.An ultrasonic launch circuit and receive circuit were designed.The single-chip control circuit was constituted by AT89S52 and gate circuit.Keil C was used for designing the software of the AT89S52. All that completed the design of ultrasonic measurement system.(4) Experiment,data processing and analysisA hydraulic experiment system was established and BP neural network was used as data processing method for the relationship between the pressure and the changes of velocity.The program of BP neural network was compiled using Matlab.The program can train and test the experiment data.Final,an analysis of test results was given.The experimental results not only reflect the approximate linear relationship between velocity changes and the pressure in the hydraulic system,but also prove the feasibility of this experimental system,which provides a helpful reference for further development of the testing apparatus.