Effect of Baffle Dimensions on Liquid Free Surface in an Agitated Vessel with Paddle Impeller

Abstract

The vortex depth in an agitated vessel with paddle impeller is measured under various impeller dimensions and various baffle conditions. The vortex depth in a non-baffled vessel is correlated well by using the Froude number and the parameter n_p^0.7 (b/H) which is defined for the power correlation by Kamei et al. The difference of the vortex depth in a baffled vessel from that in a non-baffled vessel is also correlated by using the baffle condition parameter n_b^0.8 (B_w/D). The radius at the intersection of liquid free surface and static level is only affected by the ratio of the paddle impeller diameter to the vessel diameter. A new estimation method of the radius of cylindrically rotating zone from the vortex depth and the intersection radius was proposed. The radius of cylindrically rotating zone decreases with increasing baffle condition parameter (h_B/H) n_b^0.8 (B_wD) and vanishes where the baffled condition parameter is 0.24. This condition is independent of the impeller dimensions, and is weaker than the full baffle condition.