Natural Convection Mass Transfer Experiments in Horizontal Cylinders

Researches on the natural convection in horizontal cylinders have not been extensively studied. They are rare and most reported ones are for non-uniformly heated condition. It is difficult to find the literature on simple thermal condition. The natural convection in a horizontal cylinder is similar to that in an annulus with a cooled concentric inner cylinder and a heated outer cylinder. The fluid heated by the inner surface of the cylinder flows upward along inner surface and then at the top, it flows downward along the vertical centerline of the cylinder. Two D-shaped natural convective flows are developed. The heat transfer rate decreases as the thin boundary layer develops from the bottom toward the top and becomes thicker. At the top, the fluid is stably stratified and at the bottom it is unstably stratified. Thus the heat transfer rate is the maximum at the bottom and the minimum at the top. Sarac and Korkut carried out natural convection mass transfer experiments occurring at the external and internal surface of the cylinders by measuring the deposition of copper from aqueous copper sulfated solution containing sulfuric acid as a supporting electrolyte. The inside diameter of the cylinder was 0.6cm and concentrations of CuSO4 were 0.025, 0.050, 0.10, 0.15, 0.20M. They suggested an empirical heat transfer correlation for a horizontal cylinder as follows: Shd = 0.703(GrdSc)1/4, 5.7x109 <GrdSc<1.6x1011 (1) This study measured the natural convection mass transfers inside horizontal cylinders with varying the diameters of the cylinders at various angles. And it suggests a mass transfer correlation. A copper sulfate . cupric acid electroplating system was used as the mass transfer system