Turbulent mixing in baffled stirred tanks with vertical‐blade impellers

Mixing time and power consumption have been measured in baffled, paddle‐agitated cylindrical tanks with single‐ and double‐impellers, and mixing efficiency has been defined by a reciprocal of the product of the mixing time and power consumption. The mixing efficiency and mixing time of double‐impeller agitation have been compared with those of single‐impeller agitation, and they have been related, through a circulation time, to the flow patterns obtained from the measurements of mean axial and radial velocities.