降膜分子蒸馏过程模型研究

通过对降膜分子蒸馏器蒸发表面上液膜流动和传质传热的分析,建立了液膜的传质和传热方程;并在单组分非线性BGK方程的基础上,建立了描述多组分稀薄气体流动的非线性BGK模型方程。通过适当的边界条件将液膜方程和气体方程耦合在一起,得到了降膜分子蒸馏过程的传质与传热数学模型。该模型揭示了液膜温度和浓度在径向和轴向上的变化规律以及气相空间气体的密度、温度和速度的变化规律,适用于恒壁温和绝热壁等不同操作情况。

Study on Mathematical Model of Falling-Film Molecular Distillation Process

On the basis of analysis of liquid flow, mass transfer and heat transfer as well as the new scheme for multi-component flow calculations between two closed surfaces of evaporation and condensation, a new mathematic model is developed to describe falling-film molecular distillation process. This model can be used to calculate the profiles of temperature and concentration of film and the profiles of density, temperature and velocity of vapor with the consideration of the feed rate, evaporation temperature and inert gas pressure. The model is applicable to simulate the evaporator with a constant wall temperature or with insulated wall.