Single-beam-laser multidimensional speed measuring system and method of high-speed rarefied gas flow field

Abstract

The invention discloses a single-beam-laser multidimensional speed measuring system of a high-speed rarefied gas flow field. The single-beam-laser multidimensional speed measuring system comprises a high-speed rarefied gas wind tunnel (1), a laser light source module (2), a laser beam shaping module (3), a high-voltage arc discharge module (4), a fluorescent signal collecting and recording module (5), a data processing module (6) and a time sequence synchronous control module (7). The invention further provides an application method of the system.

Description

technical field [0001] The invention belongs to the technical field of combining flow field display, rare gas and laser spectrum measurement, and specifically relates to a single-beam laser multi-dimensional velocity measurement system for high-speed rare gas flow field, and the single-beam multi-dimensional velocity measurement system for high-speed rare gas flow field. Measurement methods for speed measurement systems. Background technique [0002] Accurate measurement of high-speed flow field velocity plays a key role in mastering flow field characteristics and correcting numerical calculation models, and is of great value to the study of fluid mechanics and engineering thermophysics. The complex and unstable characteristics of the high-speed flow field require non-contact optical measurement methods for its velocity measurement. At present, the commonly used non-contact optical velocimetry methods are mainly divided into three categories: the first category is particle-...

AI Technical Summary

Problems solved by technology

However, in supersonic airflow, particles do not follow the gas molecules very well, and in pulsed equipment such as shock tunnels, it is difficult to add particles uniformly

[0003] The second type is the laser velocimetry method based on molecular scattering, such as: measuring velocity based on the Doppler effect of scattered light, such as Rayleigh scattering velocimetry (Rayleigh Scattering Velocimetry) method and planar laser-induced fluorescence based on Doppler broadening ( Doppler-based PLIF Velocimetry) method, but this type of method is more suitable for high-speed compressed flow with large Doppler effect, and is generally used in high-speed and high-density flow fields, because of low-speed flow with small Doppler effect or flow field with low particle number density will greatly increase the measurement error of such methods

These methods are not suitable for hypersonic thin gas flow fields (such as thin gas arc wind tunnels used to study re-entry vehicles), this flow field is a thin high-temperature plasma flow field generated by high-voltage arc discharge, and the main gas supply component is required It is nitrogen, which can contain a small amount of non-oxidizing gases such as hydrogen, and cannot contain oxidizing gases such as oxygen

Therefore, the artificial addition of molecules such as biacetyl, acetone or NO will not only ionize, but also may chemically react with the high-temperature plasma components in the thin gas flow field, affecting the composition and structure of the flow field, and more seriously may damage the high-voltage discharge equipment

Metal atoms such as sodium or strontium are metal atoms with heavy weight and high inertia, and their followability is a big problem in supersonic airflow, which cannot represent the speed of the airflow itself.

Images