Melting process investigation of a non-Newtonian phase change material containing multiwalled carbon nanotubes in a trapezoidal enclosure

This research examines the melting characteristics of nano-enhanced, non-Newtonian PCMs-multi-walled carbon nanotube (MWCNT). The process includes analyzing the impacts of various nanoparticle concentrations and trapezoidal angles by conducting simulations with these nanocomposites filled within the enclosure. The power-law shear-thinning effects are incorporated into the governing equations, which are then converted into a generalized dimensionless form using scaled parameters and solved using the finite element method. The findings underscore the significant role of enclosure geometry in influencing the melting dynamics and heat transfer process. Critical outcomes include the effect of nanoparticle concentration on the initiation of natural convection and the overall melting process, the influence of trapezoidal angle on the distribution of the molten liquid and melting dynamics, and the alteration of the melting interface shape due to nanoparticle concentration. The Nusselt number displayed intricate behavior during the melting process, changing with nanoparticle concentration. The study found that altering trapezoidal angles and nanoparticle concentrations could significantly affect melting time, with changes up to 62.5% observed. It was concluded that a trapezoidal enclosure with a slight outward angle (γ = 10°) was most effective in reducing interference and shortening melting time, offering valuable insights for optimizing PCM design for diverse applications.