Plasma pressure sensor based on direct current glow discharge

Abstract

This paper describes a recently developed pressure-measuring technique based on direct current glow discharge plasma. The operation principle, characteristics and design of this plasma pressure sensor are introduced and investigated. The development of the plasma pressure sensor was motivated by the need to document the high-frequency internal information more clearly in the harsh environment of turbomachines or hypersonic flows. The electrode spacing and current were two main factors that influenced the sensor's monotonic response characteristic and static sensitivity to the pressure fluctuation. Three typical electrode spacings—50 μm, 100 μm and 220 μm—were tested for the static calibration. The results revealed that the optimal electrode spacing was 220 μm, which showed a monotonically increasing trend and had the highest sensitivity for a pressure range from 0.5 atm to 5.0 atm. The dynamic response of the sensor was calibrated with a sinusoidal-wave pressure generator and a shock tube as the step-function pressure generator. The results showed that the natural frequency of the plasma pressure sensor, including its high-voltage power supply and electronic circuit, was 146.6 kHz.