< Terug naar vorige pagina

Publicatie

Investigation of a Free-Stream Air Plasma Flow by Optical Emission Spectroscopy and Comparison to Magnetohydrodynamics Simulations

Boekbijdrage - Boekhoofdstuk Conferentiebijdrage

The VKI Plasmatron is the world’s largest inductively coupled plasma facility, which allows to reproduce on ground the high-enthalpy, chemically reacting boundary layer over a re-entry body. Test conditions are suitable for qualification of thermal protection systems and for material response studies. This paper presents the experimental investigation of the free-stream air plasma flow under relevant test conditions and the comparison to numerical simulations of the plasma discharge in the test chamber. Previous works have already focused on a similar subject; however, high-resolution spectra over a broad wavelength range, spectral fitting to absolute emission intensities and comparison of experimental temperatures with CFD simulations of the plasma jet were never performed on this facility. Here, the gas-phase radiative signature of dominant atomic and molecular species is observed using a high-resolution spectrograph, combined with a two-dimensional ICCD array. From the rebuilding of local emission intensities, obtained through Abel inversion, radial temperature profiles are determined under the assumption of Local Thermodynamic Equilibrium (LTE). The procedure is based either on fitting the experimental spectra with a line-by-line code (Specair) or by analytical results assuming a Boltzmann’s distribution. The simulated spectra, computed with equilibrium chemical composition and a one-temperature model, agree very well with the experimental data. Magnetohydrodynamics simulations of the plasma jet are then performed using an in-house code and temperature profiles are compared with the experimental gas temperatures at the corresponding locations. Once the power efficiency parameter of the simulation is adequately adjusted, a noticeable agreement is found in the radial distributions at each axial position.
Boek: AIAA Scitech 2020 Forum
Series: AIAA Scitech 2020 Forum
Pagina's: 1-15
Aantal pagina's: 15
ISBN:9781624105951
Jaar van publicatie:2020
Toegankelijkheid:Closed