Natural Convection from a Helical Heating Coil to the Surrounding Fluid.

Abstract

An experimental study is reported on natural convection heat transfer from a helical heating coil to the surrounding fluid. The coil is heated electrically and the surrounding fluid is selected to be water. The range of parameters are: Rayleigh number, 879 ?£ Ra ?£ 780168, Prandtl number, 4.22 ?£ Pr ?£ 10.02, dimensionless coil diameter,7.69 ?£ Dave /d ?£ 10.77, number of coil rings, 2 ?£ N ?£ 8, and the dimensionless coil pitch 1/d= 1. The results are correlated by means of a modified Nusselt number. The proposed correlation is a convenient tool for estimating heat transfer from helical coils.