Research On Characteristic Of Pressure Sensor Based On Radio-Frequency Discharge

Nowadays researchers hard to accurately measure the flow field of scramjet isolator and aeroengine compressor because of the high temperature and high pressure environment in the scramjet isolator and aeroengine compressor.But it is difficult to find a pressure sensor to measure accurately in that hard environment.Because the machine with complex mechanical structure makes the internal environment too high temperature to work efficiently.And measuring high frequency dynamic pressure is also a challenge in compressor.It requires the pressure sensor has the characteristics of high frequency response and tiny size.A pressure sensor is proposed which is based on the plasma glow discharge in this paper.The sensor has the characteristics of temperature resistance,high frequency response and tiny size.So it is thought to measure the pressure data accurately in the flow field of scramjet isolator and aeroengine compressor.Obviously it is important to study the characteristics of the plasma pressure sensor.In this paper,a plasma pressure sensor drived by A.C power supply is be proposed.First,the response law of the plasma pressure sensor to pressure variation were studied at different power supply.Then its sensitivity to temperature has been studied in electro thermostat.And the dynamic frequency response of the plasma sensor is calibrated by the shock tube calibration platform.After that it was applied to measure the endwall static pressure in a low speed axial compressor.The experimental results showed that when the electrode gap was 220 μm,the maintaining voltage of the plasma increased monotonically as the pressure increased,with a voltage change of 90 V and pressure sensitivity of 0.22 V/kPa.The maintaining discharge voltage had barely changed as the temperature increased from 25℃ to 400℃.The dynamic calibration experiment results show that the frequency response of the plasma pressure sensor is 1.35MHz,and its dynamic frequency response is determined by the loop system including the plasma pressure sensor.From the low speed axial compressor experimental,it turned out that the plasma pressure sensor had the same ability comparing with Kulite to capture the blade passing frequency.