Theoretical And Experimental Study On Explosion Limits Of New Refrigerants

It is a significant work to develop new alternative refrigerants with good properties and own intellectual property rights. As a part of a project, the present study mainly includes explosion limits of pure and mixed refrigerants in order to guarantee security in use. The main contents are as follows:Firstly, through theoretical analysis of chemothermodynamics, combustion and thermodynamics, factors that affect explosion limits were determined, which include temperature, pressure, spark ignition energy, electrode shape, direction of flame propagation, size of explosion vessel and components of mixed gases. These theories provide support to the further study.Secondly, based on the basic principles of chemistry, a new theoretical method of calculating Lower Explosion Limit (LEL) of a pure refrigerant was established. The LEL could be calculated through the chemical constituents of the flammable refrigerants alone without considering other factors. To the binary mixed flammable refrigerants, the thesis proposes a simple method to calculate their LEL. According to the method, predited values can be obtained when there are not any available experimental data.Thirdly, because there is no standard testing method in the world, two experimental systems had been established according to GB/T 12474—90 and ASTM E681-01 to test the explosion limits of flammable refrigerants under the conditions of normal temperature and pressure. The experimental results of the same mixed refrigerants tested separately in these two devices were obtained. The difference between results tested by two devices are analyzed and compared according to the factors that affect explosion limits. The experiment and analysis can be of use in the setting-up of a standard method to test explosion limits of flammable refrigerants.Fourthly, the explosion limits of some pure and mixed flammable refrigerants were...