DOI: 10.1615/ICHMT.2017.CHT-7
ISBN Print: 9781-56700-4618
ISSN: 2578-5486
A STUDY OF THE ONSET OF NATURAL CONVECTION DURING MELTING OF PCMS IN A CYLINDRICAL ENCLOSURE
ABSTRAKT
The onset of natural convection was studied numerically during melting of n-octadecane and dodecanoic acid within the annular space of a horizontal cylindrical enclosure. COMSOL Multiphysics was used to model the two-dimensional heat transfer process in the system; heating the PCM from the inner surface of the annulus with the outer surface insulated. The inner surface of the enclosure was heated with temperatures corresponding to Stefan numbers of 0.2, 0.3 and 0.4, which caused the PCMs to melt. Melting of the PCMs was simulated in enclosures with inner cylinders having diameters of 6.35 and 25.4 mm, while keeping the outer cylinder diameter constant at 127 mm. For both the PCMs studied, natural convective heat transfer rapidly exceeded initial pure conduction, with onset occurring faster at high Stefan numbers regardless of the diameter of the heating surface. Also, the onset of natural convection was slightly slower in dodecanoic acid compared to n-octadecane.