Experimental investigation and simulation of the phase change process of enhanced paraffin by MWCNTs in a spherical container

Abstract

This study investigates the enhancement of phase change materials (PCMs) by incorporating highly thermally conductive carbon-based nanoparticles (multi-walled carbon nanotubes (MWCNTs)) into paraffin wax (PW) and the effect of added nanoparticles on the phase change process by experiments and numerical investigations.The melting and solidification processes were studied while melting was performed in a constant temperature oil bath and solidification in different fluid media (oil, water, and atmospheric air). Various parameters such as temperature distribution, liquid fraction, density, electrical conductivity, and thermal conductivity were measured for the PCM enclosed in a spherical container.The results show that adding nanoparticles to paraffin decreased the melting time by 9% and 14% for MWCNTs with 8 nm and 10–20 nm diameter, respectively. It also led to a decrease in solidification time of 23% for MWCNTs with a diameter of 8 nm and 28% for MWCNTs with a 10–20 nm diameter. Notably, the nanoparticles significantly impacted the solidification process more than melting.Additionally, this study shows that reducing the container's diameter from 68 to 48 mm resulted in a 40% reduction in melting time and a 47% reduction in solidification time. Changing the surrounding medium from oil to air and water further reduced solidification time by 16% and 48%, respectively.