A High-frequency Induction Plasma Wind Tunnel Electron Density and Electron Temperature Diagnosis System

Abstract

The invention discloses a high-frequency induction plasma wind tunnel electron density and electron temperature diagnosis system. The MW-level high-frequency induction wind tunnel generates plasma flow, and the signal modulation and power amplifier unit outputs scanning voltage of corresponding frequency according to the working state of the wind tunnel to the probe unit to collect the voltage source of charged particles, through the unique three-electrode probe combination The noise suppression circuit eliminates the high-frequency noise and industrial signal interference noise in the plasma. The current signal collected by the current acquisition unit after denoising is isolated from the ground wire through the isolator H1, and is recorded by the data processing unit at the same time as the scanning voltage signal And processed to get electron temperature and electron density. The invention eliminates the strong electromagnetic interference in the flow field of the MW extremely high-frequency induction wind tunnel, and at the same time proposes to utilize the advantages of high-frequency scanning and combine the method of moving the arm to realize the electron temperature and electron density in the flow field of the MW extremely high-frequency induction wind tunnel Diagnosis of radial distribution.

Description

technical field [0001] The invention belongs to the technical field of aircraft ground aerodynamic thermal protection test research, in particular to a high-frequency induction plasma wind tunnel electron density and electronic temperature diagnosis system. Background technique [0002] The high-power high-frequency induction plasma heating wind tunnel uses high-frequency induction-electromagnetic coupling to heat the gas, which does not have the problem of electrode ablation pollution caused by the traditional arc wind tunnel heating method, and can provide chemically pure high-temperature plasma flow The field can not only be used for aerodynamic and thermal protection tests of hypersonic vehicle thermal protection systems, but also for basic research on high-temperature real gas effects and catalytic composite characteristics of material walls. Due to its high-frequency induction-electromagnetic coupling heating method and low-pressure flow field environment, its flow fie...

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Problems solved by technology

[0003] Electrostatic probes are widely used in the field of plasma electron density and electron temperature diagnosis research because of their simple structure and diverse diagnostic data. The key step in probe diagnosis is to obtain a volt-ampere characteristic curve with a high For high-frequency induction plasma heating wind tunnels, the frequency of the high-power discharge power supply will be coupled with the plasma, resulting in strong electromagnetic interference with the same frequency as the power supply and double frequency of the power supply. If these noises are not dealt with, the volt-ampere characteristic curve will be Extremely poor noise ratio, unable to obtain electron temperature and electron density data

Due to the complex electromagnetic characteristics of the flow field in the high-frequency induction wind tunnel, there are currently no public reports on the diagnosis of electron density and electron temperature in MW-level high-power high-frequency induction wind tunnels based on electrostatic probe technology.

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