An Experimental Study Of Combined Effect For Unsteady Natural Convection And Radiation Heat Transfer Through A Cavity Between Inclined Eccentric Cylinders

Abstract

An experimental investigation was carried out for combined effect for unsteady natural convection and radiation heat transfer between inclined eccentric cylinders under constant surfaces temperature condition. The study included the effect of transient Raleigh number, which includes the effect time required to reach the steady state, the angular position of the inner cylinder and the eccentricity ratio for the inner cylinder on the convection and radiation heat transfer for unsteady state through enclosure between inclined cylinders. The study showed that the ability of the inner cylinder on transient convection heat transfer decreased as the transient Raleigh number increased which is increase as time required to reach the steady state increase, perhaps this ability increase as the angular position for the inner cylinder increase and decrease as eccentricityratio increase except at the ratio (ε=0.351) in the angular position (δ=180o) where this ability will be higher than concentric state (ε=0). While the radiation heat transfer depended only on thetemperature, difference, which is a function of time, required to reach the study state.