Thermal Transfer in Turbulent Gas Streams—Effect of Turbulence on Macroscopic Transport From Spheres

Abstract

Abstract The rate of thermal transport from spheres in a flowing stream is of interest in many industrial operations. Limited data are available concerning the effect of turbulence level on this transfer process. Measurements of the thermal transport from spheres to an air stream at four levels of turbulence were made at four velocities varying between 4 and 32 fps. Results are presented in terms of the Nusselt number. The experimental work is a portion of a detailed study of the local thermal and material transport from spheres in turbulent air streams. The data indicate a significant increase in the thermal transport with an increase in the level of turbulence at a constant Reynolds number. For example, the Nusselt number was increased from 53 to 62 upon an increase in the level of turbulence from 0.05 to 0.12 at a Reynolds number of 7200.