Development of a liquid sinusoidal pressure generator for the dynamic calibration of pressure sensor

Pressure sensors play an important role for the monitoring of gas and liquid conditions in the field of municipal water supply, oil and gas transportation, process industrial production, and many other. Calibration is an essential process before and during the use of sensors to ensure their measurement accuracy. Although the static calibration of pressure sensor is very mature, the technology for dynamic calibration is still underdeveloped. In this paper, a liquid sinusoidal pressure generator based on a symmetrical piezoelectric vibrator is developed for the dynamic calibration of pressure sensor. The structural design and working principle of the generator are explained. Piezoelectric actuation causes a high-frequency simple harmonic vibration of the metal diaphragm, which squeeze the sealed liquid medium to generate dynamic sinusoidal pressure. Finite element models are built to investigate the vibration of symmetrical piezoelectric vibrator and the acoustic structure coupling between the solid vibrator and liquid medium. Two natural vibration modes have intense vibrations of the metal diaphragm, which might be useful for the generation of dynamic pressure. The acoustic-structure coupling analyses show that sinusoidal pressure with high amplitude is generated in the two natural vibration modes with large shifts of the initial resonant frequencies. A prototype sinusoidal pressure generator is manufactured and tested. The experimental results indicate that the generator could provide sinusoidal pressure in the range from 1500 Hz to 6500 Hz. Three peaks of sinusoidal signals with good amplitude and low distortion occur at the frequencies of 2.57 kHz, 3.67 kHz, and 5.97 kHz, respectively.