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以纯水为介质，用直接接触式膜蒸馏测定了材料或性能参数不同的三种多孔疏水膜在不同温度下的渗透通量。根据测量结果计算出了各种膜在不同温度下的渗透系数，发现渗透系数均随着温度的升高而升高；这一结果说明Poiseuille流动在跨膜传质中起着非常重要的作用。据此提出了Knudsen扩散-Poiseuille流动两参数跨膜传质模型，即TPKPT模型。用此模型拟合实验数据，得到了三种实验用膜的模型参数。用这些模型参数计算膜在不同温度下的渗透系数，其值与实验测量值吻合较好，说明TPKPT模型能较好地描述膜蒸馏的跨膜传质过程。
Using pure water as the medium, the permeation fluxes of three kinds of porous hydrophobic membranes with different materials or performance parameters at different temperatures were determined by direct contact membrane distillation. According to the measured results, the permeability coefficients of various membranes at different temperatures were calculated. The results show that the permeability increases with the increase of temperature. This result shows that Poiseuille flow plays a very important role in transmembrane mass transfer. The Knudsen diffusion-Poiseuille flow two-parameter transmembrane mass transfer model is proposed, which is TPKPT model. Using this model to fit the experimental data, the model parameters of three experimental films were obtained. Using these model parameters, the permeability coefficient of the membrane at different temperatures was calculated. The calculated values agree well with the experimental data, which shows that the TPKPT model can better describe the transmembrane mass transfer process of membrane distillation.