Review of computational multi-phase approaches of nano-fluids filled systems

•Eulerian-Lagrangian and Eulerian-Eulerian Multiphase approaches were overviewed.•The single-phase model is less accurate and produces a significant deviation.•The mixture model is superior and reduces CPU usage and computational time. Recently, Nano-fluids have gained great attention as a result of their significant possibility for heat transfer improvement. The heat transfer of Nano-fluids can be numerically investigated employing the single-phase and two-phase models. Nanofluids are a homogenous mixture of the base fluid and nanoparticles with minor slip in between in the single-phase approach. This model is a widely used approach due to its cost-effectiveness and simplicity. Meanwhile, the two-phase models are divided into the Eulerian-Lagrangian and Eulerian-Eulerian depending on the treatment of nanoparticles and fluid phases. The Eulerian-Eulerian approach consists of three numerical approaches: the mixture, volume of fluid (VOF), and Eulerian. Many articles emphasize two-phase approaches because they consider the motion between solid particles and fluid and their precise predictions. However, the accuracy of this approach is extensively based on several conditions, including the flow type and nanoparticle properties. Despite this, the accuracy of various computational approaches to simulate Nano-fluids is still debatable. Therefore, this review paper aims to analyze all the published studies about the homogenous, multi-phase Eulerian-Lagrangian and Eulerian-Eulerian (volume of fluid, mixture, Eulerian) approaches.