Heat transfer characteristics during cryoablation

Abstract

In the present study, the overall heat transfer coefficient of Zacarian disc in different media is investigated experimentally and predicted numerically. Copper disc is chosen for the study because of its high heat capacity; a property by which a material can withstand the heat for a longer time. In dermatology, heat transfer rate of the disc at the skin surface plays a crucial role for the necrosis of the tumour while applying the cryogen. The disc immersed in liquid nitrogen can be directly applied on to the tumour surface for the ablation of tumour. Cryoablation of tumour occurs by the formation of ice crystals within cells and the cellular metabolism gets affected which leads to the apoptosis of the cell. The cooled disc was allowed to thaw in different media viz. air, water, and gel. The formation of ice and maximum penetration were studied when the sub-cooled disc was exposed in water and gel. To mimic biological skin tissue, 0.2% agarose gel was used. Heat transfer characteristics for the biological skin tissue were studied. The overall heat transfer coefficient between the disc and air was found to be 19.5 W/m2K while it is 65.5 W/m2K for a system consisting of disc and water.