Visualization of natural convection heat transfer on a sphere

Natural convection heat transfer phenomena on spheres were investigated by adopting mass transfer experiments based on analogy concept. The diameters of spheres were varied from 0.01 m to 0.12 m , which correspond to the Rayleigh numbers of 1.69×10 8 –2.91×10 11 . The measured mass transfer coefficients agreed well with the existing correlations. The copper electroplating patterns on the spheres visualized the local heat transfer depending on angular distance. The streak plating patterns were observed on the upper part of the sphere, resulting from the wavy flow patterns caused by the instability.