Ho Chii-Dong, Chiang Ming-Shen, Ng Choon Aun
Department of Chemical and Materials Engineering, Tamkang University, Tamsui, New Taipei 251301, Taiwan.
Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman, Kampar 31900, Perak, Malaysia.
Membranes (Basel). 2025 May 10;15(5):144. doi: 10.3390/membranes15050144.
Theoretical and experimental investigations were conducted to predict permeate flux in direct contact membrane distillation (DCMD) modules equipped with turbulence promoters. These DCMD modules operate at moderate temperatures (45 °C to 60 °C) using a hot saline feed stream while maintaining a constant temperature for the cold inlet stream. The temperature difference between the two streams creates a gradient across the membrane surfaces, leading to thermal energy dissipation due to temperature polarization effects. To address this challenge, 3D-printed turbulence promoters were incorporated into the DCMD modules. Acting as eddy promoters, these structures aim to reduce the temperature polarization effect, thereby enhancing permeate flux and improving pure water productivity. Various designs of promoter-filled channels-with differing array configurations and geometric shapes-were implemented to optimize flow characteristics and further mitigate polarization effects. Theoretical predictions were validated against experimental results across a range of process parameters, including inlet temperatures, volumetric flow rates, hydraulic diameters, and flow configurations, with deviations within 10%. The DCMD module with the inserted 3D-printed turbulence promoters in the flow channel could provide a relative permeate flux enhancement up to 91.73% under the descending diamond-type module in comparison with the module of using the no-promoter-filled channel. The modeling equations demonstrated technical feasibility, particularly with the use of both descending and ascending hydraulic diameters of 3D-printed turbulence promoters inserted into the saline feed stream, as compared to a module using an empty channel.
开展了理论和实验研究，以预测配备湍流促进器的直接接触式膜蒸馏（DCMD）模块中的渗透通量。这些DCMD模块在中等温度（45°C至60°C）下运行，使用热盐水进料流，同时保持冷入口流的温度恒定。两股流之间的温差在膜表面形成梯度，由于温度极化效应导致热能耗散。为应对这一挑战，将3D打印的湍流促进器纳入DCMD模块。作为涡流促进器，这些结构旨在减少温度极化效应，从而提高渗透通量并提高纯水生产率。实施了各种填充促进器的通道设计——具有不同的阵列配置和几何形状——以优化流动特性并进一步减轻极化效应。针对一系列工艺参数（包括入口温度、体积流量、水力直径和流动配置）的实验结果验证了理论预测，偏差在10%以内。与使用无促进器填充通道的模块相比，在流动通道中插入3D打印湍流促进器的DCMD模块在菱形下降型模块下可提供高达91.73%的相对渗透通量增强。与使用空通道的模块相比，建模方程证明了技术可行性，特别是在盐进料流中使用插入3D打印湍流促进器的下降和上升水力直径时。
