Axial force at the vessel bottom induced by axial impellers.

This paper deals with the study of the axial force affecting the flat bottom of a cylindrical vessel stirred with a pitched-blade turbine. Measurements were conducted with a set of pressure transducers located along a radius at the vessel bottom. The dimensionless dynamic pressure depends significantly on the impeller off-bottom clearance. The data were evaluated to obtain the liquid flow rate at the vessel bottom: they were interpreted according to schematic flow pattern consisting of three regions characterised by liquid jet streams flowing downwards (beneath the impeller), upwards (at the vessel wall) and horizontally outwards (in an intermediate bottom region).