Measurement of hydraulic oil pressure in pipeline based on Short-time Fourier method

The steel pipe filled with No.46 hydraulic oil was taken as the experimental object, using a dedicated change the hydraulic oil pressure steel pipe pressure regulating equipment, using the center frequency of 5 MHz broadband ultrasonic transducer in the outer wall of steel pipe to detect the hydraulic oil, short time Fourier transform (STFT) is used to collect the velocity of ultrasonic in the hydraulic oil under different pressure spectrum and attenuation spectrum, analysis of ultrasonic velocity, the ultrasonic attenuation coefficient and the relationship between the hydraulic oil pressure. The results show that with the increase of the pressure of the hydraulic oil in the steel pipe, the velocity of ultrasonic increases and the attenuation coefficient decreases, and the relationship between the pressure and the velocity and attenuation coefficient satisfies a certain function. The pressure calculated by this function is less than 3% when compared with the experimental results.