Oxidation of a C2HF5/air mixture examined by weak flames in a micro flow reactor with a controlled temperature profile.

Oxidation of C 2 HF 5 (pentafluoroethane, R125) that has been extensively used as a refrigerant and fire suppressant agent was examined by weak flames in a micro flow reactor with a controlled temperature profile (MFR) for safety reasons. To investigate the oxidation process of a stoichiometric C 2 HF 5 /air mixture, species measurements for a stoichiometric C 2 HF 5 /air weak flame at the maximum wall temperatures of the reactor from 750 to 1400 K were conducted using a Fourier Transform Infrared Spectroscopy (FTIR). Measurement results showed that two-stage oxidation which consist of the consumption of C 2 HF 5 and formation of C 2 F 6 at the first stage and the reactions of C 2 F 6 at the second stage. Computational results reproduced the observed two-stage oxidation of C 2 HF 5 /air mixture. Since CO remained at the exit of MFR even in the case of a maximum wall temperature at 1400 K, incomplete oxidation of the C 2 HF 5 /air mixture was suggested. Therefore, the weak flame structure at a much higher maximum wall temperature of 2000 K was investigated computationally. The results showed that three-staged complete oxidation of a C 2 HF 5 /air mixture. The three-stage oxidation consisted of the two-stage oxidation similar to that observed in the case of the maximum wall temperature of 1400 K and additional oxidation from CO to CO 2. The latter slowly proceeded because H atom in the fuel was mostly and already consumed by HF formation in the first stage. [ABSTRACT FROM AUTHOR]