Numerical investigation of the effect of different forces on the relative velocity of nanofluid by developing a new solver in OpenFOAM

In this study the free convection heat transfer of a nanofluid, including water and nanoparticles suspended in a square cavity is simulated numerically for a laminar flow. Open source framework i.e. OpenFOAM was used to develop the equations and make changes in the desired terms such as relative velocity between the nanoparticles and the base fluid. To achieve the purpose of the research and to ensure the accuracy of the numerical algorithms used in this framework, at first the free convection inside the cavity was investigated using two-phase mixture model and the results of the present study were compared with the results presented in the literature. Then, with the help of existing mathematical equations, important parameters in simulating the forces acting on nanoparticles in the free convection inside the cavity were studied and as a result, the forces that had a significant impact were selected as the most important and corrected relative velocity was entered in the continuity, momentum, heat transfer and continuity equation of the second phase (nanoparticles) as a parameter called JP. This simulation was performed using the PIMPLE algorithm (SIMPLE + PIZO). To consider free convection, nanofluid’s density changes with Boussinesq relationship. The mixture two-phase model has used for modeling with higher speed and more accuracy and also effective thermophysical properties of nanofluid, related to JP parameter have been used in order to increase the accuracy of work. As a result, the effect of these forces on different conditions was investigated.