In turbulent flow, how large are the three components of flow for baffled and unbaffled tanks?
• A: That depends on the impeller type. For a flat bladed paddle in an unbaffled tank, Nagata showed that the tangential component of flow is as much as 75-80% of the tip speed (near the impeller). Nagata also showed that at the bottom and near the top, the tangential component was still as high as 70% of the tip speed. Now that’s a vortex! Put in baffles and Nagata found that the tangential flow component went down to about 25% of the tip speed between the baffles and the blade tips. He still determined about 80% of the tip speed at about 80% of the blade diameter at the impeller height. Nagata also showed that the radial component increased by a factor 4 with the baffles! Bernd Hoefler, Siegfired Buhlmann, and Bernd Lohr (1979) did a beautiful job of documenting the three components of velocity for a fully baffled tank and 4 different types of impellers: RT, PR, Ekato-MIG, and a very tall RP. They basically confirmed Nagata on the RP. They found the maximum tangential velocity right
