Transient natural convection heat transfer analyses from a horizontal cylinder

Abstract

Experiments are conducted to analyze the power-on transient natural convection heat transfer around a horizontal cylinder heated in air. The heat flux ranges from 177 W/m2 to 2426 W/m2 and Rayleigh number from 4.13 × 104 to 4.35 × 104. The effects of transient heat transfer data on different angular position of the thermocouple (0°, 90°, 180°) are reported. The results indicate that the transient heat transfer around the cylinder is strongly affected by the position of thermocouples. The test rig working condition is verified by comparing the steady-state natural convection heat transfer data with those obtained from the literature. It is observed that the transient heat transfer data obtained at 90° and 180° are higher than that of stagnation point (0°). Finally, based on the transient data, correlations are presented to predict the heat transfer behavior around the heated cylinder.