Study On The Flammability And Explosion Properties Of 2,3,3,3-Tetrafluoropropene

With the continuous improvement of society and living standards,the refrigeration systems are becoming more and more common in our life.The demand for refrigeration systems such as refrigerators,refrigerators,air conditioners and so on is also increasing,and the used refrigerants also increase.Previous freons had been discontinued for destruction of the ozone layer.Most of the pure substances and mixtures of hydrofluorocarbons?HFCs?,hydrocarbons?HCs?and hydrochlorofluorocarbons?HCFCs?currently available for refrigerants are mostly flammable to cause combustion and explosion risk.In view of the flammability risk of flammable refrigerants,we chose a new type of environmentally friendly 2,3,3,3-tetrafluoropropene?R1234yf?refrigerant with zero ozone depletion potential?ODP?and low global warming potential?GWP?.The object of study is to analyze the explosion risk and explosion suppression of R1234yf through experiments and simulations.First of all,the influence of N₂ and CO₂ on the flammability limits of R1234yf at 20-50°C was experimentally studied and the critical flammable ratio and the critical oxygen concentration were obtained.The results showed that the inerting effect of CO₂ was better than N₂.With the increase of temperature,the flammability limits expanded.Then two methods of the extended Le Chatelier formula and adiabatic flame temperature were introduced to predict the flammability limits of the two mixtures under different temperature and ratio conditions,then the error analysis was carried out.Finally,the explosion experiments of R1234yf at different temperature,pressure and volume concentration were carried out.The results show that the explosion pressure and explosion pressure increase first and then decrease with increasing volume concentration at 0.1MPa and 25°C.The maximum explosion pressure reaches 0.742MPa when the volume concentration is 7.6%,while the maximum rate of explosion pressure rise is 4.04MPa/s.The explosion pressure increases with the increasing of initial pressure,and the rate of the explosion pressure rise shows an M-type trend as the increasing of initial pressure.Under the same pressurization condition,the explosion pressure and the rate of explosion pressure rise rate show an M-type trend with the increasing of concentration.The explosion pressure decrease with the increasing of temperature,and the rate of explosion pressure rise increase with the increasing of temperature.In addition,the maximum explosion pressure and the rate of maximum explosion pressure rise are both a function of the initial temperature in the temperature change experiment.