Flow field analysis-informed optimisation of structural parameters in propulsion agitator design

Propeller-type agitators have broad applications in industrial production. However, there has been limited research on their structural parameter optimisation and flow field performance. In this study, a physical model is established for a propeller-type agitator in practical engineering applications, and its accuracy is validated through physical experiments. The dimensionless structural parameters are optimised to quantitatively characterise the turbulence intensity distribution and mixing effectiveness using evaluation metrics, including the uniformity index and mixing uniformity. Optimisation of the structural parameters is performed using a combined approach integrating computational fluid dynamics (CFD) with the response surface methodology (RSM). The optimisation objectives focus on the impeller blade curvature, diameter, and installation height from the bottom of the tank to achieve optimal mixing performance. The results demonstrate that an appropriate installation height of H_f = 0.335 improves the mixing efficiency without increasing the power consumption. The blade curvature exhibits non-monotonic optimisation characteristics, with an optimal curvature B = 0.908. The optimal configuration is achieved with a blade curvature B = 0.908, diameter ratio D_R = 1.713, and installation height H_f = 0.335, which provide an enhanced mixing performance. The findings of this study establish a theoretical foundation for optimising the design of fluid mixing machinery and provide actionable guidelines for the design and operational refinement of industrial mixing processes.