中文摘要：

针对有限空间中易发生相变的液体化学品意外泄漏的情况,运用Fluent软件对其泄漏扩散进行数值模拟。湍流模型选用RNG k-ε模型,考虑液体发生相变时的蒸发潜热,分析了不同时刻的危害区域范围,数值预测其在有限空间的温度场、速度场及浓度场的时空分布。结果表明,在风的下游和地面附近化学品浓度较高,并且液体蒸发相变导致温度降低,化学品浓度越高,温度越低;液体蒸发相变是一个渐变过程,在刚开始泄漏时空间气相质量浓度较低,随时间继续气相质量浓度逐渐升高,并且在水平和垂直方向其扩散呈不同特点。

英文摘要：

The leakage and diffusion of a fluid--which is prone to phase change--accidentally released in a limited space have been simulated with the Fluent code. The renormalization group （RNG） k-8 turbulence model was used to describe the turbulence of the fluid. With consideration of the latent heat of the liquid phase change, the hazard area was analyzed at different times and the temperature, velocity and concentration distributions were nu- merically predicted in the limited space. The results show that the concentration distributions downwind and near the ground were higher than elsewhere. Moreover, liquid phase change resulted in a temperature decrease, with higher concentration leading to lower temperature. The liquid evaporation was a gradual process. At the start of flu- id leakage, the gas mass fraction in the limited space was low and it increased gradually with time. Furthermore, gas diffusion showed different characteristics in the horizontal and vertical directions.