Research On Properties Of Moist Air By Using Molecular Dynamics Simulations

Due to high-temperature and pressure moist air is currently being considered for use in the new thermodynamic circulation, molecular dynamics simulation (MDS) is adopted to investigate the properties of moist air which used in moist air turbine and compressed air energy storage (CAES) system in this paper. Based on the theory of statistical thermodynamics, the way to calculate the properties parameter of moist air is presented by different state equations such as: virial state equation, Duan et. al. state equation and RDF state equation via L-J and TIP4P models. Main contents listed as bellow:1. Combined with The state phase,the RDF was analyzed by Stirling equation,Lagrange undefined multiplicator,partition function,Planck hypothesis and uncertainty relation via canonical ensemble and microcosmic energy level.2. Combined with viral state equation, Duan et. al. state equation and RDF state equation, a suitable molecular dynamics simulation model is chosen for calculating the properties of moist air by comparing the performance of Lennard-Jones model and TIP4P model when they are used in calculating the properties of water vapor.3. Properties of moist air are simulated by a new moist air state equation and calculated by Van der waals mixing-rule.4. Parameter of moist air are given for humidity ratios from 0.1 to 2.0 kg/kgda, specific volume s from 1/400m3/kg to 1/25m3/kg and temperature from 0℃to300℃by calculating with moist air state equation.5. Combined with gas-liquid phase balance theory and RDF state equation, the saturated moist air`s parameters was simulated and a new phase balance theory was established.6. Parameters of saturated moist air are given for pressure from 5MPa to 20Mpa, temperature from 0℃to 400℃, dry air specific volume s from 0.01m3/kg to 0.5m3/kg by new gas-liquid phase balance model.7. New solid heat model was established by the research of two-phase principle and molecular dynamic simulations.