Thermal decomposition mechanism of environment-friendly mixture refrigerant by theoretical study

摘要

R513A (R1234yf/R134a) and R454C (R1234yf/R32) are promising mixture working fluids used inOrganic Rankin Cycle (ORC) system because of their low global warming potential (GWP) and goodthermal performance. This paper mainly contributed to the thermal decomposition mechanism study ofR513A and R454C. Firstly, the initiation reactions of working fluids pyrolysis are researched by densityfunctional theory (DFT). Then, the pyrolysis mechanism and pyrolysis products of pure working fluids(R1234yf, R134a and R32) and mixture working fluids (R513A and R454C) are studied by ReaxFFmolecular dynamics simulations, respectively. It is found that F radical is the main factor for the interactionof the two working fluids in R513A. Finally, simulation calculations are carried out on working fluids underdifferent pressures. The change of pyrolysis rate with the pressure is obtained. The results reported that thepyrolysis rates of the working fluids increase with the increases of pressure. These results will providegeneral guiding significance for the application of R513A and R454C.