Impact of Side Flow on Mixing Impeller

Authors:

R.J. Weetman

R.N. Salzman

The article examines the impact of side flow on axial and radial mixing impellers, analyzing velocity vectors, fluid forces, and mechanical loads within mixing vessels. Using advanced instrumentation, including laser velocimeters and strain-gaged shafts, the study provides precise, repeatable measurements that link flow behavior to impeller performance and tank turnover. The results highlight the importance of simultaneous process and mechanical measurements for reliable scale-up and efficient full-scale mixer design.

Key Learnings

• Side flow significantly affects the performance of both axial and radial impellers, altering power draw, fluid forces, and tank turnover.
• Precise measurement of velocity vectors and fluid forces using laser velocimeters and strain-gaged shafts is critical for accurate analysis and scale-up.
• Simultaneous monitoring of flow dynamics and mechanical loads ensures reliable design of full-scale mixing equipment.
• Asymmetric flow patterns from side jets can increase bending loads on impeller shafts, impacting mechanical integrity.
• Scale-up from laboratory to full-size plants requires linking fluid dynamics with process results and mechanical design considerations.
• High-quality instrumentation and integrated laboratory setups improve repeatability, accuracy, and efficiency in mixer testing.
• Understanding micro- and macro-scale turbulence, vortices, and flow asymmetries is essential for optimizing mixer efficiency and process outcomes.
• Empirical mixer models based on advanced measurements reduce the risk of failure and capital costs in full-scale installations.