ABSTRACT
Temperature distribution and solid–liquid interface positions were measured during melting and solidification of paraffin wax (mixture of pentacosane and hexacosane) contained in a cylindrical cell, with an insulated wall to achieve one-dimensional heat flow. The lower face of the cell was subjected to a sudden temperature change, while the condition of no heat flux was maintained at the upper face.
Measurements of temperature distribution and interface positions during solidification from below were in excellent agreement with theoretical predictions based on pure conduction in both phases. Both the analytical solution of Neumann and the numerical solution of Murray and Landis were applied and found to have similar results.
Although the experimental results of melting from below showed distinct temperature distribution in both phases, the agreement with the theoretical estimates based on pure conduction was very poor.
To include the effect of convection, liquid thermal conductivity was replaced by an effective thermal conductivity according to a correlation of the form, Ke /Kt = cRn a . Values of c and n have been determined to achieve a good agreement between the experimental and theoretical values of the interface positions, and found to be different from those usually obtained with no phase change.
