Abstract
The effect of immersion depth of the impeller on the power of a horizontal shaft agitator used as a gas-liquid contactor has been investigated.
In lower Froude number region, power number may be expressed by the sum of two terms: standard power number (Np)S and additional power number Δ.
It is found that (Np)s is the power number owing to the drag force of the impeller blade moving through liquid and Δ is the power number owing to the deformation of liquid surface caused by impeller blade which was immersed into and emergent from the liquid.
When the liquid surface is below the center of the rotating shaft, (Np)s is proportional to the dimension-less integral I derived from theoretical considerations and Δ is proportional to the dimensionless immersion depth of impeller.
In higher Froude number region, power number is proportional to the dimensionless integral.
