Research on the flammability and explosion characteristics of typical low GWP refrigerants

Abstract

Under the development requirements of green environmental protection, refrigerants are constantly updated. 2,3,3,3-tetrafluoropropene (R1234yf), difluoromethane (R32) and isobutane (R600a) are promising environmentally friendly refrigerants that are widely used in domestic air conditioners, automotive air conditioners and refrigerators respectively. Although the new refrigerants meet green requirements, they also pose safety risks, with refrigerant leakage leading to explosion accidents. This paper numerically calculated the adiabatic combustion temperature, explosion pressure, laminar burning velocity and combustion products of refrigerants under different environmental factors. The numerical analysis was verified with experimental data on burning velocity in the literature, which confirmed the reliability of the numerical simulation. The results showed that the adiabatic combustion temperature of R600a was the largest, R32 was the second largest and R1234yf was the smallest under the same conditions, while the explosion pressure of R32 was the largest, R1234yf was the second largest and R600a was the smallest under the same conditions. The burning velocity of R600a gradually decreased with the increase of the ambient humidity, while the burning velocity of R32 first increased and then decreased with the increase of the ambient humidity, and reached a maximum value (6.8 cm/s) when the ambient humidity was about 60%. The combustion products of R600a were mainly CO2 and H2O, the combustion products of R32 and R1234yf were mainly HF and CO2, due to R1234yf′s F/H > 1, the concentration of CF2:O and CF4 in the combustion products of R1234yf was not negligible.