Thermal investigation of natural convection heat transfer from a confined fin attached cylinder

Steady state condition of a two-dimensional free convection flow around a horizontal and isothermal fin attached cylinder which is located between two nearly adiabatic walls is studied experimentally by using a Mach- Zehnder interferometer. The walls inclination angle (θ) influence on heat transfer is studied for Rayleigh number ranging from 1000 to 15500. Experiments are performed for a fin attached cylinder between two nearly adiabatic walls. Two different diameter cylinders with diameters D=10 and 20mm are used forcovering a wide Rayleigh range. Results show that, heat transfer process differs for different Rayleigh numbers. For Rayleigh numbers less than 5500, heat transfer from cylinder surface is less than the heat transfer from an individual cylinder and it’s the result of no slip boundary condition on top of the cylinder. In this range by the use of walls heat transfer from the cylinder decreases slightly and walls inclination does not change heat transfer rate from the cylinder surface. For Rayleighnumber ranging from 5500 to 15500, heat transfer from the surface of the cylinder is less than the heat transfer from the surface of an individual cylinder. By raising the walls inclination angle from 0o to 20o, the chimney effect between walls and the fin become less. So the heat transfer amount is going to that of a fin attached cylinder which is unconfined between adiabatic walls.

کلیدواژه ها:

Natural convection ، Fin attachedcylinder ، Confining walls Interferometry ،