Research on power and flow field and temperature field characteristics during the amplification process of spiral stirred kettle based on CFD theory

• The power curves of stirred kettles with different volume amplification are similar. • Volume amplification has a significant effect on the temperature distribution inside the kettle. • The heat flux of non-Newtonian fluid decreases and then increases with the increase of Re . Spiral stirred kettles offer significant energy savings due to their unique structure. Due to the lack of a theoretical basis for special fluid handling and equipment volume amplification design, its industrial application still faces challenges. Therefore, the power, flow rate, and temperature characteristics of batch and continuous spiral stirred kettles with different amplification are compared and analyzed for Newtonian and non-Newtonian fluid conditions. The findings show that the torque of both types of spiral stirred kettles rises with the increase of Reynolds number ( Re ), and the fluctuation of power number ( Np ) tends to stabilize and converge; when dealing with Newtonian fluids, the power number ( Np ) of the continuous spiral stirred kettles is generally lower, the average wall heat flux increases with the increase of Re , and the heat transfer is better under the condition of high Re , and there is no significant change after the equipment amplification. When handling non-Newtonian fluids, the power characteristic curves of the two spiral stirred kettles are highly similar, and the average wall heat flux decreases with equipment amplification. Additionally, the equations relating Np to Re and equipment volume amplification ( n A ) were fitted for the intermittent and continuous spiral stirred kettles, respectively, for different fluids. The conclusions obtained provide a theoretical basis for designing spiral stirred kettles of different sizes.