HFP-co-PVDF/N6 hydrophobic/hydrophilic dual-layer membrane was used to study desalination with direct contact membrane distillation (DCMD). A one-dimensional (1-D) model was proposed to predict the flux and thermal efficiency. Heat and mass transfer equations were solved numerically for the combined hydrophilic and hydrophobic layers. The membrane characteristics of the hydrophobic layer were considered for the calculation of the mass transfer coefficients, while the hydrophilic layer was ignored since it was assumed to be filled with water. However, the hydrophilic layer was taken into account during the calculations of conductive heat transfer. Therefore, the equations are different, compared to single-layer hydrophobic membranes. It was found that with the same hydrophobic membrane characteristics, the single-layer membranes performed with better flux and thermal efficiency than the dual-layer membranes. Furthermore, the improvement of flux and thermal efficiency by an addition of the hydrophilic layer has not been observed experimentally, and it is suggested that the improved performance for dual-layer membranes reported previously is due to improved permeability by using thinner and more porous hydrophobic layers that can be mechanically reinforced by the hydrophilic layer. The validation of the model was conducted by comparing the experimental results for single- and dual-layer membranes with the modelling results. The predicted flux and thermal efficiency by the modelling were within 10% error to the experimental results.

HFP-co-PVDF/N6 疏水/亲水双层膜用于研究直接接触膜蒸馏 (DCMD) 的脱盐。提出了一个一维 (1-D) 模型来预测通量和热效率。对结合的亲水层和疏水层进行了数值求解的传热和传质方程。计算传质系数时考虑了疏水层的膜特性，而忽略了亲水层，因为假设它充满了水。然而，在计算传导传热时考虑了亲水层。因此，与单层疏水膜相比，方程式是不同的。结果发现，在具有相同疏水膜特性的情况下，单层膜比双层膜具有更好的通量和热效率。此外，在实验中还没有观察到通过添加亲水层提高通量和热效率，这表明先前报道的双层膜性能的提高是由于使用更薄和更多孔的疏水层提高了渗透性可以通过亲水层进行机械加固。通过将单层和双层膜的实验结果与建模结果进行比较，对模型进行了验证。通过建模预测的通量和热效率与实验结果的误差在 10% 以内。实验中尚未观察到通过添加亲水层提高通量和热效率，这表明先前报道的双层膜的性能提高是由于使用更薄和更多孔的疏水层提高了渗透性由亲水层机械增强。通过将单层和双层膜的实验结果与建模结果进行比较，对模型进行了验证。通过建模预测的通量和热效率与实验结果的误差在 10% 以内。实验中尚未观察到通过添加亲水层提高通量和热效率，这表明先前报道的双层膜的性能提高是由于使用更薄和更多孔的疏水层提高了渗透性由亲水层机械增强。通过将单层和双层膜的实验结果与建模结果进行比较，对模型进行了验证。通过建模预测的通量和热效率与实验结果的误差在 10% 以内。并且有人认为，先前报道的双层膜的性能改进是由于通过使用更薄和更多孔的疏水层提高了渗透性，疏水层可以通过亲水层进行机械增强。通过将单层和双层膜的实验结果与建模结果进行比较，对模型进行了验证。通过建模预测的通量和热效率与实验结果的误差在 10% 以内。并且有人认为，先前报道的双层膜的性能改进是由于通过使用更薄和更多孔的疏水层提高了渗透性，疏水层可以通过亲水层进行机械增强。通过将单层和双层膜的实验结果与建模结果进行比较，对模型进行了验证。通过建模预测的通量和热效率与实验结果的误差在 10% 以内。