Correlation of discharge flow rate in a vessel with pitched blade paddle impeller

The discharge flow rate Q d for both paddle impeller and pitched blade paddle impeller were measured with the flow follower method. The discharge flow rate number obtained for the paddle impeller Nq d was correlated with the power number Np and the impeller dimensions, based on the correlation form derived from the angular momentum balance between the impeller tip and the vessel wall. The correlation of Nq d obtained for the paddle impeller was modified with the blade angle 0 to give the correlation of Nq d for the pitched blade paddle impeller. The resultant correlations were (Nq d ) NB= 0.14(D/d) 1/2 β[(D 2 H/d 3 )Np] 1/2 (3.3γn p 0.7 bsin 1.6 θ/H) θ/π for γn p 0.7 bsin 1.6 θ/H 0.3 for a non-baffled vessel and (Nq d ) B =0.25(n p 0.7 b/d) -1/4 β[(D 2 H/d 3 )Np] 1/2 (2.5γn p 0.7 bsin 1.6 θ/H) θ/π for a baffled vessel, respectively. These correlations reproduced not only the present experimental results but also the results measured by other investigators within ±30% experimental error.