Phase change dynamics in a cylinder containing hybrid nanofluid and phase change material subjected to a rotating inner disk

In this numerical study, the phase change dynamics of a 3D cylinder containing hybrid nanofluid and phase change material (PCM) is investigated with a finite element solver. The PCM consists of spherical encapsulated paraffin wax, and the flow is under the forced convection regime. The dynamic features of the phase change process are studied for different values of the Reynolds number (between Re=100 and 300), the rotational Reynolds number of the inner disk (Rew=0 and 300), and the size of the rotating disk (length between 0.1L and 0.55L; height between 0.001H2 and 0.4H2). The flow dynamics and separated flow regions are found to be greatly influenced by the rotational speed and size of the inner disk. As Re is increased, the difference between the transition times at different rotational disk speeds decreases. At Re=100, a 21% reduction in the phase transition time is observed when the inner disk rotates at the highest speed as compared to the motionless case. Up to a 26% variation in the phase transition time occurs when the size of the inner rotating disk is varied. A 5 input-1 output feed-forward artificial neural network is applied to achieve fast and reliable predictions of the phase change dynamics. This study shows that introducing rotational effects can have a profound effect on the phase change dynamics of a hybrid nanofluid system containing phase change material

RSM-based sensitivity analysis of hybrid nanofluid in an enclosure filled with non-Darcy porous medium by using LBM

The present analysis is performed to investigate the free convection MHD non-Darcyflow in hybrid nanofluid (TiO2/Cu-water) occupying a differentially heated square closedspace. The non-dimensional governing equations for mass, momentum and energy are solvedunder boundary conditions by using the D2Q9-based Lattice Boltzmann Method. A key noveltyof the work is the inclusion of an RSM-based sensitivity analysis. The current investigation hasbeen done considering the variation in Rayleigh number (103 ≤ Ra ≤ 106), Darcy number(0.0001 ≤ Da ≤ 0.1) and Hartmann number (0 ≤ Ha ≤ 50). It has been shown that the diagonallength of an eddy is boosted as the Rayleigh number increases. In addition, it has been shownthat the Nusselt number tends to drop as Ha values rise. From RSM, high Darcy parameter,low volumetric fraction and low Hartmann number are identified as the optimum functioningconditions for heat transfer rates