The Onset of Silica Scaling Around Circular Cylinders

Abstract

The pressure distribution around a cylinder has been measured at different Reynolds numbers in a water tunnel, in which temperature and fluid velocity can be controlled. These pressure distributions are compared with published data for dynamically similar flows and related to silica deposition experiments around circular cylinders, which were carried out in the same water tunnel, under the same flow conditions. Silica scale thickness varies around the cylinder with the greatest deposition rate occurring, at least initially, in regions of high wall shear stress. Tests on a cylinder fitted with a tripping wire show that scale formation is disrupted in the vicinity of the tripping wire confirming that particle inertia has an important influence on the deposition mechanism.