Reverse electrodialysis (RED) is a promising technology that directly converts salinity gradient energy into electrical energy through the directional permeation of ions across the ion exchange membranes (IEMs). Fundamental understanding of the multi-physical RED process requires a reliable description of all the related phenomena involved in the process. In this work, a two-dimensional RED model based on the Nernst-Planck framework was developed. The fluid dynamics and ion transport were modelled in a full-length cell pair domain by employing the continuity, Navier-Stokes and Nernst-Planck equations complemented by the Donnan exclusion theory and local electroneutrality. The experimentally inaccessible IEM diffusion coefficients were analytically determined using the counterion condensation theory incorporating the tortuosity effect. A numerical simulation was carried out using the developed model. The solution velocity, ion concentration and electric fields were obtained and the characteristics of ion transport were analyzed. The effects of solution inlet velocity, IEM fixed charge concentration and cell pair length on RED performance were investigated and the mechanisms governing the variations of performance parameters were revealed based on ion transport. The present model contributes to a clearer understanding of the connection between the ion transport behavior and the stack performance.

反向电渗析（RED）是一种很有前途的技术，它可以通过离子在离子交换膜（IEM）上的定向渗透，将盐度梯度能直接转换为电能。对多物理RED过程的基本理解要求对过程中涉及的所有相关现象进行可靠的描述。在这项工作中，开发了基于Nernst-Planck框架的二维RED模型。利用连续性，Navier-Stokes和Nernst-Planck方程，并结合Donnan排斥理论和局部电子中性，在全长细胞对域中对流体动力学和离子迁移进行建模。实验中无法达到的IEM扩散系数是使用结合了曲折效应的抗衡离子缩合理论进行分析确定的。使用开发的模型进行了数值模拟。得到了溶液的速度，离子浓度和电场，并分析了离子迁移的特性。研究了溶液入口速度，IEM固定电荷浓度和电池对长度对RED性能的影响，并基于离子迁移揭示了控制性能参数变化的机制。本模型有助于更清楚地了解离子传输行为与电池堆性能之间的关系。研究了IEM固定电荷浓度和细胞对长度对RED性能的影响，并基于离子迁移揭示了控制性能参数变化的机制。本模型有助于更清楚地了解离子传输行为与电池堆性能之间的关系。研究了IEM固定电荷浓度和细胞对长度对RED性能的影响，并基于离子迁移揭示了控制性能参数变化的机制。本模型有助于更清楚地了解离子传输行为与电池堆性能之间的关系。