IC2 will be presenting a talk on our recently published paper at AIAA SciTech on Friday, 1/10/20. The paper, titled “A Novel, High-Frequency, Reciprocal Calibration Method for Dynamic Pressure Sensors Used in High-Speed Flows”, focuses on demonstration of our patent-pending reciprocal calibration process for high-frequency dynamic pressure sensors.
Shock tubes are the traditional go-to method for calibration of high-frequency (>100kHz) dynamic pressure sensors, as they can be used to generate an impulsive pressure wave containing high-frequency content. Unfortunately, this often results in high-amplitude pressure fluctuations that are not ideal for calibrating low-amplitude sensors, due to effects of non-linearities. Additionally, the frequency content of an ideal shock tube pressure trace scales inversely with frequency, leading to signal-to-noise limitations at high frequencies and resulting in large relative random errors. Despite these shortcomings, shock-tube methods offer the best means currently available for calibrating dynamic pressure sensors for high-frequency applications.
The approach developed by IC2 and described in the paper addresses these limitations by enabling high-frequency calibration of dynamic pressure sensors without any of the problems arising from pressure-driven calibrations. The technique leverages the reciprocal nature of piezoelectric transduction to enable calibration using electrically-driven actuation to drive the diaphragm and a laser vibrometer to measure the resulting deflection. Using this method, accurate calibrations up to 1 MHz and beyond are achieved without any of the issues arising from shock-tube methods. In the paper, this method was used to calibrate up to 1.25 MHz (well beyond the sensor resonance) and compared against traditional low-frequency calibrations, demonstrating the capability of this approach over the entire sensor measurement bandwidth.