Calculation of the decomposition products of C5F10O-Air mixtures from 500 K to 3500 K with a chemical kinetic model

Abstract

C₅F₁₀O-Air mixtures have a great potential to replace SF₆ in medium-voltage power equipment. However, during the partial overheating or arc discharge, C₅F₁₀O-Air mixtures are inevitably to decompose to form various byproducts. The local chemical non-equilibrium and local thermal non-equilibrium appears due to the finite reaction rates and insufficient energy change between species. This paper establishes a chemical kinetic model to calculate the decomposition byproducts of C₅F₁₀O-Air mixtures from 500 K to 3500 K by taking into account the local thermal non-equilibrium and local chemical non-equilibrium simultaneously. The chemical kinetic model contains 50 species and 249 reactions. All the reactions are assumed to be reversible except the reactions producing photos. The local thermal non-equilibrium is characterized by the difference of the electron temperature (T_e) and the temperature of heavy species (T_h). In this work, the ratio of T_e to T_h is determined to be a function of the electron number density. Therefore, the value varies with electron number density. The temperature dependent decomposition composition of C₅F₁₀O-Air mixtures with C₅F₁₀O content to be 5%, 10% and 15% are obtained. In order to investigate the effects of Air on the decomposition of C₅F₁₀O, the decomposition products of pure C₅F₁₀O from 500 K to 3500 K are also investigated. In addition, the main chemical processes in 0.1C₅F₁₀O-0.9Air mixture are investigated by capturing the main reaction pathways. The main reaction pathways can help interpret the formation mechanism of the decomposition products.