Mass-Transfer-Controlled Impingement Corrosion at the Jet Inlet Zone of an Annulus under Turbulent Flow

Diffusion-controlled impingement corrosion of the lower part of the inner cylinder of an annulus caused by a perpendicular inlet jet was studied using the diffusioncontrolled dissolution of copper in acidified dichromate technique. Variables studied were solution velocity, physical properties of the solution, diameter of the perpendicular feed nozzle, and the effect of drag-reducing polymers. For blank solution, the rate of mass-transfer-controlled impingement corrosion was correlated by the equation Sh = 2.74Sc^0.33 Re^0.46(dn/d)^-0.4. Drag-reducing polymers were found to decrease the rate of mass-transfer-controlled impingement corrosion by an amount ranging from 29.9 to 68.9% depending on electrolyte concentration, polymer concentration, and feed nozzle diameter. The importance of the present results to the design of annular equipment was noted.