Chemical thermometry in miniature HRRST using 1,1,1-trifluoroethane dissociation

The decomposition of 1,1,1-trifluoroethane (C2H3F3), was measured in a 12.7 mm bore high repetition rate miniature shock tube (7.8 < P5 < 10.6 bar and 1250 < T5 < 1600 K) using tunable diode laser absorption spectroscopy and chemical modeling. The concentration of HF produced from the dissociation of 1,1,1-C2H3F3 was simulated using the rate coefficients of Matsugi et al. (2014) in conditions near the high pressure limit, in a chemical thermometry test. Modeling of the post-reflected shock wave conditions properly included the temperature rise from non-ideal gas dynamic effects in the small shock tube. Excellent agreement between simulations and experimental profiles of HF concentration was obtained with thermometry temperatures near those calculated by the normal shock relations. Below 1400 K, the initial post-reflected shock temperature agreed with the normal shock relations within the experimental uncertainty but was approximately 40-60 K lower for 1450 < T5 < 1600 K.