Flow Phenomena and Heat Transfer Around a Sphere Submerged in Water Jet and Bubbling Jet

Abstract

Velocity and turbulence around a sphere made of synthetic resin submerged in water and bubbling jets in a cylindrical vessel with bottom blowing were measured by making use of LDV. The melting process of an ice sphere was recorded by video camera. The local Nusselt number Nu_θ of the ice sphere was determined from the initial change of the local radius. The mean Nusselt number Nu was calculated from Nu_θ by numerical integration over the surface of the sphere. The effects of velocity and turbulence intensity on Nu_θ and Nu were investigated. An empirical expression for Nu was proposed as a function of Reynolds number and turbulence intensity. A method of predicting the complete melting time of an ice sphere was presented.