Experimental Studies of Free Convection Heat Transfer

Abstract

The free convection heat transfer from a vertical cylinder of about 360 mm in height and about 76 mm in diameter to ethyleneglycol or water has been studied experimentally. The local heat transfer coefficients, which are measured directly, are scarcely affected by the development of the vortex street in the boundary layer, but are discontinuously increased by the transition to a turbulent flow. The results for ethyleneglycol are as follows : G_rP_r < 8.5×10⁹ : N_ux=0.49 (G_rxP_r)^1/4 8.5×10⁹ < G_rP_r < 8×10¹⁰ : N_n=0.87 (G_rP_r)^1/4 The temperature distributions in the boundary layer are also measured.