Experimental Study of Free Convection Heat Transfer From a Fin Attached Cylinder Confined Between Tilt and Low Conductive Plates

Abstract

Steady state and two-dimensional natural convection heat transfer flow around a horizontal and isothermal cylinder with a longitudinal fin attached to it that is located between two tilt and very low conductive plates is studied experimentally by using a Mach-Zehnder interferometer. Effects of the plates slope angel (θ) on heat transfer from the tube is investigated for Rayleigh number ranging from 1000 to 15500. Experiments are done for a fin attached cylinder placed between two low conductive plates. Two different diameter tubes with diameters of D=10 and 20mm are utilized for broad Rayleigh number range. Results specify that, heat transfer experience differs for special Rayleigh numbers. For Rayleigh numbers ranging less than 5500, rate of heat transfer amount from the cylinder surface is less than that of a lone cylinder and it’s the result of no slip boundary condition on the fin surface. For this range of Rayleigh number by the use of plates, heat transfer from the cylinder surface decreases slightly and plates leaning does not alter heat transfer speed from the cylinder surface. For Rayleigh number ranging from 5500 to 15500, heat transfer rate from the cylinder surface is lower than the heat transfer rate from the surface of an individual cylinder. Though, by adding placing the low conductive plates as plates to experimental model, heat transfer system differs and chimney effect between fin and the plates increases the heat transfer from the cylinder surface. By increasing the plates slope angel from 0° to 20°, the chimney effect between plates and fin weakens and heat transfer rate from the tube surface is going to the amount of heat transfer rate from a fin attached cylinder which is not placed between plates.