Heat Transfer Characteristics in an Inclined Open Ended Concentric Annulus with Rotating Inner Shaft

Abstract The natural, forced and mixed convection in an inclined concentric open ended annulus with stationary and rotating inner shaft and uniformly heated stationary outer cylinder has been experimentally investigated. The study covers a wide ranges of heat flux 80 q 500 W/m2, rotational Reynolds number =0 (stationary inner cylinder) and 50 100 for laminar Couette flow ( ), and 150 300 for turbulent Taylor vortex flow, Rayleigh number 18560 58434, Richardson number 0.29 Ri 33.39, and angle of inclinations 00 900. The results showed that the heat transfer process improves as the angle of inclination deviates from horizontal to vertical position and the mean Nusselt number at =300, 450, 600, and 900 (vertical position) increases by 1.6%, 5.5%, 7.3%, and 8.3%; respectively, from that at horizontal position ( =00). A general empirical correlation for average Nusselt number (Num) has been deduced as a function of , Ra, and . The results are compared with previous works and show a good agreement. Keywords: Annulus, convection heat transfer, rotating inner cylinder