Based on CFD and the Metzner-Otto theory: Mechanisms governing the influence of non-Newtonian fluid properties on flow field and power characteristics in spiral stirred kettles

Spiral stirred kettles are frequently employed for processing high-viscosity non-Newtonian fluids due to their exceptional stability and high energy efficiency. However, the complex helical structure and rheological properties of non-Newtonian fluids render flow field and power prediction challenging. Consequently, this study employs computational fluid dynamics (CFD) alongside the Metzner-Otto theory to simulate the flow field and power characteristics when spiral stirred kettles process various non-Newtonian fluids. Findings reveal that higher consistency coefficient ( m ) and higher flow index ( n ) of non-Newtonian fluids correlate with increased stirring torque and Np values. To reduce the effect of fluid rheology on the power prediction, the traditional Np - Re correlation was corrected by introducing m and n . The resulting equation is Np = 184.21096 m 0.0523 n 0.29841 Rea –0.98235 , (within 20% error and applicable to Rea : 0.3-16, m : 14–44, n : 0.07–0.57). The conclusions not only fill a gap in existing research on screw agitators but also provide a comprehensive theoretical basis for optimizing the design of stirring equipment for efficiently processing non-Newtonian fluids in actual industrial production.