Comparison of Hybrid and CNT-Nanofluids Used as Heat Transfer Fluid for Forced Convection Through a Phase Change Material (PCM) Filled Vertical Cylinder

Abstract

Effects of different nano-additive types inclusion in the base fluid are numerically analyzed on the laminar forced convection through a phase change material embedded pipe. Hybrid nanofluid with Ag-MgO nanoparticles and CNT-nanofluid are used as heat transfer fluids while finite element method is used for the solution of governing equations. As the phase change material, spherical-shaped encapsulated paraffin wax material is used. Numerical simulation is performed for various values of Reynolds number (between 100 and 500) and nanoparticle volume fractions (between 0 and 0.02) for hybrid particles and CNT-particles. The dynamic features of heat transfer fluid and phase change material temperatures are altered by varying the Reynolds number and solid volume fraction of nanoparticles. The average liquid fraction increases with higher values of Reynolds number and solid volume fraction of hybrid particles. The reduction in the full phase change transition time during charging reduces by about 61–65% for nanofluids when lowest and highest Reynolds number cases are compared. There is 17% variation in the phase transition time between the lowest and highest solid volume fraction configurations when hybrid nanofluid is used. However, when CNT-nanofluid is used as heat transfer fluid, there is slight variation in the complete phase transition time occurs with varying solid volume fraction of nanoparticles.