EXPERIMENTAL-STUDY OF FREEZING IN A RECTANGULAR ENCLOSURE

An experimental investigation into the freezing of n-paraffin solution s in a rectangular enclosure is reported. One vertical side of the enc losure was isothermal while the other walls were adiabatic. Using n-he xadecane and a binary mixture of 50% iz-hexadecane and 50% n-octadecan e, the effects of aspects ratio and wall temperature on the shape and advancement of the solid-liquid interface and the rate of freezing wer e investigated. For both the pure material and the binary mixture, hea t transfer during freezing for the early stages was conduction-dominat ed. The effect of natural convection is evident for longer times, with convection currents being confined mainly to the top of the enclosure . However, for enclosures of small aspect ratio, this effect may exten d to the bottom of the enclosure. It was also found that the aspect ra tio has no effect on the solidification rate. Frozen-mass fractions we re found to be greater for the binary mixture as compared to the pure material. For both materials, the freezing rate was greater for lower wall temperatures. (C) 1997 Elsevier Science S.A.