Analysis of Burning Candle

J.S. Crompton, L.T. Gritter, S.Y. Yushanov, and K.C. Koppenhoefer
AltaSim Technologies LLC, Columbus, OH, USA

Analysis of burning candles is extremely complex; combustion produces a highly non-linear temperature profile through the flame in which local temperatures may exceed 1400 °C. Heat transfer includes radiation, conduction and convection components and the low melting point of the candle wax leads to a phase change that allows mass transport via capillary flow prior to combustion in the flame. COMSOL Multiphysics has been combined with generalized strategies to analyze heat transfer and fluid flow during candle burning. Radiation was included through a radiating surface that was non-locally coupled to the radiating gas volume. The dynamic behavior of the plume was incorporated by artificial diffusion to give a time-averaged approximation. Heat transfer within the liquid wax used an anisotropic thermal conductivity to account for convection in the horizontal direction. The analyses predict the velocity flow field for a half-burned three-wick candle and demonstrate spreading of the flow away from the flame. Predicted temperature distributions in the wax and candle container compare favorably with experimental measurements.