Effects of Impeller and Baffle Dimensions on Power Consumption under Turbulent Flow in an Agitated Vessel with Paddle Impeller

Power Consumption under turbulent flow in a baffled agitated vessel with paddle impeller was measured for different impeller dimensions. The power number at the standard baffle condition was then correlated well with a parameter np0.7 (b/d), where b, d and np are impeller blade width, impeller diameter and the number of impeller blades, respectively. The power correlation under fully baffled conditions was derived using the parameter np0.7 (b/d). On the other hand, from a model analysis of the drag force acting on a baffle plate, the power number under weakly baffled conditions was correlated well with the parameter (Bw/ D) nb0.8, where Bw, D and nb are baffle plate width, vessel diameter and the number of baffle plates, respectively. The resultant correlation was expressed as Np-Npo=4.5 (BW/D) nb0.8Npmax0.8 where Npo and Npmax were power number under non-baffled conditions and that under fully baffled conditions, respectively. From the derivation of the power correlation over wide range of baffle and impeller dimensions, the fully baffled condition was expressed by the following equation (BW/D) nb0.8=0.27Npmax0.2