Natural convection heat transfer in a vertical concentric annulus

Abstract EN

Experiments were carried out to study the local and average heat transfer by natural convection in a vertical concentric cylindrical annulus.

The experimental setup consists of an annulus has a radius ratio of 0.555 and inner cylinder with a heated length 1.2 m subjected to the constant heat flux while the outer cylinder is subjected to the ambient temperature.

The investigation covers heat flux range from 58.2 W / m2 to 274.31 W / m2.

Results show an increase in the natural convection as heat flux increases leads to an improve in the heat transfer process.

An empirical equation of average Nusselt number as a function of Raylieh number was deduced.