Heat Transfer by Free Convection From Heated Vertical Surfaces to Liquids

Abstract

The present investigation deals with the study of heat transfer by natural convection from vertical cylindrical surfaces to water and ethylene glycol. The results are correlated within the laminar range for (N_Gr·N_Pr) from 2(10⁸) to 4(10¹⁰) according to the expression $NNu=0.726(NGr⋅NPr)1/4$ and within the turbulent range for (N_Gr·N_Pr) from 4(10¹⁰) to 9(10¹¹) the correlation is best represented by the expression $NNu=0.0674[NGr(NPr)1.29]1/3$ The foregoing correlations represent the experimental data with a mean deviation of 5.6 per cent and 3.5 per cent for the laminar and turbulent ranges, respectively. The ranges of some of the important variables involved in the tests are given in Table 1 of the text.