基于激光干涉测量的高频液体正弦压力校准

High Frequency Liquid Sinusoidal Pressure Calibration Based on Laser Interferometry

在装置设备研制与工程应用中会使用大量动态压力传感器进行评估与测试,为了提高测量精度和数据可靠性,针对动态压力传感器的幅值灵敏度在高频率正弦压力校准中的量值溯源问题,提出一种基于激光干涉技术测量液体介质折射率随压力改变的方法用于高频液体正弦压力校准装置。利用压电叠堆效应和管腔谐振原理,可以驱动液体介质产生频率高达30 kHz的正弦压力信号,根据洛伦兹-洛伦茨理论建立压力与液体光程的数学模型,利用激光干涉仪测量液体中光程改变,得到正弦压力幅值大小,使正弦压力幅值可以得到溯源。结合实际校准过程,对压力分布不均、温度变化、结构形变、振动等影响因素进行了理论研究与实验分析,并利用基于激光干涉测量的高频液体正弦压力校准装置开展对动态压力传感器幅值灵敏度校准不确定度的完整评估。结果表明:激光干涉法高频液体正弦压力校准装置的正弦压力幅值覆盖范围0.01~1.00 MPa,静态压力环境可以实现0~10 MPa,在频率范围1~30 kHz下幅值灵敏度校准的扩展不确定度在7.6%以内。

A large number of dynamic pressure sensors are used to evaluate and test in the development of equipment and engineering application.In order to improve measurement accuracy and data reliability and solve the problem of traceability of amplitude sensitivity of dynamic pressure sensor in high frequency sinusoidal pressure calibration,a method based on laser interferometry to measure the refractive index of liquid medium changing with pressure is applied to calibration the device of high frequency liquid sinusoidal pressure.Using piezoelectric stack effect and cavity resonance principle,the sinusoidal pressure signal with frequency up to 30 kHz can be driven by liquid medium.Based on Lorentz-Lorenz theory,a mathematical model of pressure and liquid optical path is established.Laser interferometer is used to measure the change of optical path in liquid,and the magnitude of sinusoidal pressure is obtained,so that the sinusoidal pressure amplitude can be traced back to basic quantity.Combining with the actual calibration process,the influence factors such as uneven pressure distribution,temperature change,structural deformation,vibration are analyzed theoretically and experimentally.Based on the high frequency liquid sinusoidal pressure calibration device of laser interferometry,the uncertainty of amplitude sensitivity calibration of dynamic pressure sensor is evaluated.The results show that the sinusoidal pressure range of calibration device of high frequency liquid sinusoidal pressure by laser interferometry is 0.01~1.00 MPa,the static pressure environment can achieve 0~10 MPa,and the expanded uncertainty of amplitude sensitivity calibration is within 7.6%in the frequency range of 1~30 kHz.