Halogenated alkanes and halogenated olefins

especially fluorine substitutes

are currently the most widely used synthetic refrigerants. With the implementation of a series of increasingly stringent environmental regulations

most optional fluorinated substances are flammable

thus limiting their scope of use in domestic and commercial scenarios. Novel flame-retardant methods need to be developed based on the combustion mechanism. An important method is to study the combustion process of pure or mixed refrigerants through the reaction mechanism and reaction path. In this study

the ignition delay

temperature and pressure changes

and typical component combustion processes of low-carbon fluoroolefins represented by R1234yf were studied

and the combustion mechanisms of R32 and R1234yf were compared. These results are consistent with the combustion models of alkanes and olefins. R1234yf’s ignition delay is higher

and the addition and capture reactions are complicated; through the study of the reaction path

it was found that the intermediate stable products of the two flammable working fluids have many overlaps. When R1234yf is 10%

at an equivalent ratio of 1.0

the combustion equilibrium temperature can be reduced by 87.5 ℃ compared to that for pure R32; when R32 is 5%

the combustion equilibrium temperature can be reduced by 21.0 ℃ compared to that for pure R1234yf. The flammability of the mixture was lower than that of any of the two components. With the addition of a small amount of R32

the ignition time was increased

and the peak of free radicals boosting the exothermic reaction was significantly reduced