EXPERIMENTAL STUDY OF RADIATION HEAT TRANSFER OVER VERTICALLY PLACED CIRCULAR DISKS

Abstract

The radiation heat transfer over vertically placed circular disks under vacuum and air medium were experimentally investigated. Two type’s disks black and grey were considered for the study, which were placed vertically inside a heated chamber called an oven. A constant temperature was imposed inside the chamber. The chamber was partially vacuumed to prepare vacuum medium by controlling the air pressure with -0.8 to 0.6 bar.  To understand the heat transfer, time requirement to obtain certain temperatures and heat transfer coefficient were calculated. Correlation between temperature and heat transfer coefficient were also analyzed. The findings highlighted that black disk provided the highest heat transfer coefficient and the lowest time requirement to achieve a certain temperature. Polynomial relationships between temperature and heat transfer coefficient for black and grey disks with R² less than 1 were obtained through the trendlines.