Enhancing Mixing Efficiency: A CFD-Driven Design of a Helical Pipe-Type Motionless Mixer with a Kenics-Type Element

Abstract An approach to process intensification is the use of motionless mixers. Among various motionless mixers, the helical pipe-type motionless mixer has attracted considerable attention. However, its mixing performance can vary greatly depending on the location of raw material injection. In this study, we developed a helical pipe-type motionless mixer that provides consistent mixing performance regardless of the injection position of the raw materials. This helical pipe-type motionless mixer has only one Kenics-type element in the center of the helical pipe. The mixing performance of this design was evaluated using computational fluid dynamics (CFD). The mixing performance was evaluated using the mixing coefficient M c defined as an indicator of mixing efficiency between two liquids. The M c for the helical pipe-type motionless mixer without elements has at most 0.5. However, the results showed that the helical pipe-type motionless mixer having more than 4 turns with one Kenics-type element resulted in $${M}_{c}\ge 0.95$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>M</mml:mi> <mml:mi>c</mml:mi> </mml:msub> <mml:mo>≥</mml:mo> <mml:mn>0.95</mml:mn> </mml:mrow> </mml:math> in the region where Reynolds number was greater than 30.