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ISSN Online: 2377-424X

ISBN Print: 1-56032-797-9

International Heat Transfer Conference 11
August, 23-28, 1998, Kyongju, Korea

NATURAL CONVECTION DOMINATED MELTING INSIDE UNIFORMLY AND DISCRETELY HEATED RECTANGULAR CAVITIES

Get access (open in a dialog) DOI: 10.1615/IHTC11.930
pages 109-114

Sinopsis

A numerical study has been conducted for natural convection dominated melting inside uniformly and discretely heated rectangular cavities. A computational methodology based on the enthalpy method for the phase change is first outlined and validated with experimental data. The model is next employed to determine the effect of the sources dimension β and span η, of the aspect ratio of the cavity A and of the wall-PCM thermal diffusivity ratio α on the melting process. Results show that for a uniformly heated wall, the melting time reach a maximum for A ≈ 1O. For A ≤ 10, convection dominated melting is enhanced and the melting time is reduced. For A ≥ 10, the larger heated surface area promotes conduction dominated melting and the resulting melting times are also reduced. For discretely heated cavities of aspect ratio A ≤ 4.0 with a low wall thermal diffusivity ratio (α ≈ 1.5), the source span η is the most influential parameter. For 0.625 ≤ A ≤ 2.5 and η ≥ 0.45, the melting times are larger and the top sources quickly overheat. If η ≤ 0.45, the melting times are shorter and the temperatures of the sources remain equal and moderate during the melting process. Threshold values αmin above which melting becomes independent of the source distribution were determined for cavities of aspect ratios ranging from 0.625 to 10.