2023/09/29 by Andrea Fagnani, Fagnani, Andrea, Bernd Helber +5
Engineering · Physics and Astronomy · #Calibration and Measurement Techniques #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Instrumentation and Detectors (physics.ins-det) #Ionosphere and magnetosphere dynamics #Plasma Diagnostics and Applications #Plasma Physics (physics.plasm-ph)
paper · pdf · doi:10.48550/arxiv.2309.17254
openalex publication_date 2023/09/29 · openalex created_date 2023/10/03 · openalex updated_date 2026/07/28
Two-color ratio pyrometry is commonly used to measure the surface temperature of aerospace materials during plasma wind tunnel experiments. However, the effect of the plasma radiation on the measurement accuracy is often neglected. In this paper we formulate a model of the instrument response to analyze the systematic error induced by the gas radiation along the optical path. CFD simulations of the plasma flow field, together with a radiation code, allow to compute the gas spectral radiance within the instrument wavelength range. The measurement error is numerically assessed as a function of the true object temperature and emittance value. Our simulations explain the typical behavior observed in experiments, showing that a significant bias can affect the measured temperature during the material heating phase. For an actual experiment on a ceramic-matrix composite, a correction to the measured data is proposed, while comparative measurements with a spectrometer corroborate the results.