Research On The Key Technology Of Plasma Anemometry Based On Radio-frequency Glow Discharge

At present,the hypersonic research plays an increasingly important role in the field of aerospace,which has become the commanding heights for countries all over the world.Turbulence is one of the most difficult problems in the hypersonic research.So the measurement technology with a high precision and wide application is urgently required to determine the hypersonic flow turbulence boundary and the transformation mechanism of the fluid,then build an accurate turbulence model.The speed measurement technology of wind based on the radio-frequency glow discharge plasma has the advantages of high dynamic response,high Signal Noise Ratio,compact structure,and so on,which meets the requirement of the hypersonic measurement.Therefore,the study of radio frequency glow discharge plasma wind speed measurement has important theoretical and practical value.In this thesis,the research on the plasma anemometer focuses on the numerical simulation and the experimental analysis.For numerical simulations study,the two-dimensional plasma simulation program which developed by the scholars of the Berkeley University and based on modeling method of PIC/MCC is applied to establish a plasma model.The plasma anemometer model is built by coupling velocity field with above model.The characteristics of plasma electron density,ion density,the distribution of electric field and potential with different wind speed are acquired in this thesis.Simulation results show that the wind speed could cause the decrease of the number of charged particles inside the space,thereby change the discharge current,which verify the feasibility of plasma anemometer.For the experiment,the plasma wind speed measurement platform is established.First of all,the effect of different discharge parameters on the discharge current are studied,to determine the parameter of the plasma anemometer.Then the horizontal wind speed is applied to the research the effect of discharge with different wind speed.The Root Mean Square of discharge current is applied to obtain the calibration curve of the wind speed and the discharge current.The experimental results show that when the wind speed is small,the change of the discharge current is not obvious,with the increase of wind speed,the current has a linear relation with wind speed.But when the wind speed is more than a certain value,the discharge is blown out.