Micro dynamic pressure calibration with frequency method

A news dynamic calibration device was developed to calibrate micro dynamic pressure measurement system with frequency method. A piston-in-cylinder device actuated by vibrator is used to generate micro sinusoidal pressure form 1Hz to 500Hz in an airproof pressure chamber and the average absolute pressure can be adjusted from negative pressure to positive pressure. Raster system measures the piston's displacement. Amplitude and phase of sinusoidal pressure is calculated from absolute pressure, displacement and other known quantities. So no reference sensor is used and the pressure's amplitude and phase can be traced to the basic quantities such as length, mass, etc. The calculation is also corrected for wave motion, gas leakage and heat-conduction. Calibrations of flush-mounted sensors with the amplitude uncertainty less than 2% and the phase uncertainty less than 2° have been performed. Reference sensors can be used in the micro sinusoidal pressure generator to perform calibrations with relative method. Calibrations of two kinds of representative micro dynamic pressure measurement systems/sensors are described.