基于VTPR方程计算N2/CF3I充填特性

采用比容平移法修正原始的Peng-Robinson状态（VTPR）方程，提高三氟碘甲烷（CF₃I）液相饱和区密度的计算精度。基于VTPR方程，结合经典的范德瓦尔混合规则，计算了N₂作为增压介质时，CF₃I充填1/2灭火瓶和2/3灭火瓶所需的N₂质量，并与试验值和文献值进行对比。结果表明，不同充填工况的计算值与试验值基本吻合，并且优于PROFISSY软件的结果。获得了充填压力分别为2.5 MPa和4.2 MPa、CF₃I不同充填密度下的总压力与温度的关系式，并计算了灭火剂热膨胀充满灭火瓶的临界温度和临界压力，该压力-温度关系式可用于以CF₃I为灭火剂的机载灭火系统工程设计。

Calculating filling properties for N2/CF3I based on volume translation Peng-Robinson equation

The volume translation method is used to correct the original Peng-Robinson state (VTPR) equation for representing the density of trifluoroiodomethane (CF₃I) in the saturated region. Based on VTPR equation associated with the classical van der Waals mixing rule, the mass of N₂ required to pressurize CF₃I is calculated. For the case of filling one-half and two thirds of extinguisher, the results show that calculated mass of N₂ agrees well with the experimental data and it is better than the values of PROFISSY software. With different filling density of CF₃I, the relationship of total pressure versus temperature is obtained when the super-pressurized pressure are 2.5 MPa and 4.2 MPa. Besides, the critical pressure and critical temperature are also acquired when the fire agent bottle is liquid-full. The relationship of pressure versus temperature for the agent of CF₃I will help to design fire suppression system in aircraft.