Flammability inhibition effect assessment with mildly flammable refrigerant and inert gases on difluoromethane. (December 2022) - Shi, Yuqi
Abstract: The flammability of refrigerants seriously affects the safe use of new generation environment-friendly refrigerants. Mixing inert gas or mildly flammable refrigerants with other flammable refrigerants has a specific inhibition effect, but the mechanism is still unclear. The burning velocity inhibition effect was theoretically studied by analyzing the influence of working fluids such as R1234yf and CO2 on the burning velocity of R32 with and without water and analyzing the reaction pathways. Results have shown that a small amount (5% molar concentration) of weakly flammable R1234yf has a more obvious inhibition effect on the burning velocity of R32 than the same amount (5% molar concentration) of inert gas CO2 ; when the mole fraction of the additives is large (50% mole concentration), the result is the opposite. The presence of water slightly increases the burning velocity, and the increase of the burning velocity is affected by the ratio of fluorine. Through the reaction path analysis, the reactive group CHF3 after thermal decomposition of R1234yf reacts with R32, which changes the reaction path of R32 directly, reduces the rapid reaction of R32, and reduces the initial burning velocity of combustion.