Molecular Dynamics Simulation Of The Vapor-Liquid Equilibrium Of HFO-1234yf And Its Mixtures

Hydrofluorolefins and fluoropropene compounds have lately attracted great attention as alternative working fluid due to their low global warming potential(GWP). For instance, the working fluid HFO-1234 yf is currently regarded as the most promising replacement for the high GWP working fluid in air conditioning systems and heat utilization system. It is very significant to study the thermophysical properties for the new working fluid. In recent years, with the rapid development of computer technology, molecular dynamics simulations(MD) are increasingly used in the study of thermodynamics properties. In this thesis, molecular dynamics simulation was carried out to study the liquid and vapor-liquid equilibrium properties of the HFO-1234 yf and the binary mixtures of the R134 a and HFO-1234 yf, the main content is listed as follows:(1) By simulating the liquid physical properties of the HFO-1234 yf, the liquid density and diffusion coefficient properties are obtained under the condition of different temperature and pressure.(2) By simulating the vapor-liquid equilibrium physical properties of the HFO-1234 yf, the vapor-liquid phase density distributions are obtained at different saturation pressure and temperature and the properties of their relationship are studied between the vapor-liquid interface and temperature.(3) By simulating the liquid physical properties of the binary mixtures of the R134 a and HFO-1234 yf,the liquid density and diffusion coefficient properties are obtained at different temperature and mass ratio of 1: 3,1: 1,3: 1.(4) By simulating the vapor-liquid equilibrium physical properties of the binary mixtures of the R134 a and HFO-1234 yf,the vapor-liquid phase density distributions are obtained at different temperature, pressure and mass ratio of 1: 3,1: 1,3: 1. The temperature glide and azeotropic of the mixtures are discussed and it is found that the maximun of temperature slip is 0.028 K.