Improved modeling of Janus membrane considering the influence of hydrophilic layer characteristics

Abstract

Abstract Some of the previous investigations neglect the mass transfer contribution of the hydrophilic layer for modeling the Janus membrane that is used for direct contact membrane distillation (DCMD). This work studies the impact of adding such resistance on the performance of the DCMD, especially on the temperature polarization coefficient (TPC), thermal efficiency, and permeate flux. The commercial software Ansys 2020 was used to describe the transport behavior through the Janus membrane. The bulk-flow model was employed to evaluate the permeate flow through the hydrophilic layer for the first time. Simulation results were compared with the experimental results from the literature for validating the model, and a satisfactory agreement was found. Results demonstrated that the permeate flux increased by about 61.3 % with changing the porosity of the hydrophilic layer from 0.5 to 0.9 for the membrane with the lowest hydrophilic layer thickness. Moreover, the thermal conductivities of both layers contribute significantly to the DCMD’s overall performance enhancement. Vapour flux might be enhanced by increasing the hydrophilic layer’s thermal conductivity while decreasing the hydrophobic layer’s thermal conductivity. Finally, the DCMD thermal efficiency was investigated, for the first time, in terms of both layer characteristics.