Abstract
Recently, nano-encapsulated phase change material (NEPCM) has received great attention due to its ability to absorb and release heat, making it a perfect choice for many engineering and industrial applications. The current work examines the natural convection of NEPCM confined in a cubic enclosure having two wavy sidewalls and under the effect of an external magnetic field. The enclosure is heated from below via a duct or cavity having a U shape; both wavy sidewalls experience cold temperatures, and the other walls are thermally insulated. The impacts of different operational and geometrical parameters on heat transfer inside the enclosure were numerically investigated. These parameters include the external magnetic field applied, Rayleigh number (Ra), sidewall wavenumber (N), Hartmann number (Ha), nanoparticle volume fraction (φ), and heat source position. Heat transfer within the enclosure was found to be most affected by the Ra and Ha numbers, while the other factors studied had little to no effect. The maximum local Nusslet number at Ra = 106 was four times greater than that at Ra = 103. As for the effect of the Ha number, increasing Ha from 0 to 100 decreased the average Nusselt number by 38 %.
•Natural convection of NePCM confined in a cubic enclosure with two wavy sidewalls is analyzed.•The effect of heating with U-shaped duct or cavity on heat transfer is reported.•The effect of cold wavy walls on heat transfer is analyzed.•Effect of magnetic field on enclosure heat behavior is discussed.•Nanoparticle volume fraction, heat source position, Rayleigh, sidewall wave, and Hartmann numbers are examined.