Theoretical And Experimental Study On R22 Substitutes And Leakage, Diffussion, Fatalness Of Refrigerants

Current substitutes for R22 have many shortcomings. It's important to develop new environment-friendly and energy-saving R22 replacements that have self-owned intellectual property rights, and to study the leakage, diffusion, safety and other relative traits of substitutes. The main contents of this paper are as follows.Based on the CSD equation of state, a software package developed for optimal choice of alternative refrigerants is worked out. Some possible environmentally friendly alternatives for R22 were selected, and their performances were simulated. Finally, RTJU3 and RTJU4 are selected to replace R22. Compared to R407C, new refrigerants have such advantages as environmentally friendly, low slide temperature, good performances in moderately high temperature heat pump working conditions. Experimental and theoretical analyses show that RTJU3 have high security and is fit for replacing R22 in moderate-high temperature heat pumps. To obtain the instantaneous release condition of pure flammable refrigerants in tanks, an instantaneous release model is established. Considering the heat exchange between the refrigerant and environment, dynamic models of pure and mixed refrigerants leaking from vapor and liquid space were established to describe actual release processes better. A formula of judging the burnable fatalness of mix-refrigerant increase or decrease in the process of leakage is deduced.The main interior and exterior factors influencing pure refrigerants releasing from the vapor space, and the leakage's effect on the flammability of mix-refrigerants are analyzed. Aiming at the characteristic of varied mass flow rate of refrigerants leaking from tanks, a new unsteady big-space diffusing model is put forward. The concentration of refrigerants after finite-time release and diffusion was gained by the numerical and analytical solutions of the model. To improve application value, the new diffusion model is modified, and a new modifying heavy gas effect method is set up. Through application and analyse on instance, the dangerous area of burning and blasting of new refrigerants, the factors affecting the dangerous area are investigated. Besides, this work studies the laminar premixed flame of flammable refrigerants, the mechanism of flame propagation, the main factors influencing the flame propagation velocity, improving the existed test-bed that tests the flammable limits of gas, testing the flame propagation velocity and flammable limits of many refrigerants in normal temperature and pressure air, analyzing the source of experimental error and putting forward a method to reduce it, investigating the laminar premixed flame propagation specialty and regular of flammable refrigerants, bringing forward a method to comprehensively evaluate flammable fatalness of refrigerants.New environment-friendly and energy-saving replacements for R22 are developed and the leakage, diffusion, safety and other relative characteristics of refrigerants are studied in this paper with the experiment and computer simulation as main tools. The methods and conclusions may be helpful for the producer and seller of refrigerants.