Experimental comparison of wavy and pitched blade impellers for vortex suppression in un-baffled stirred tanks

Authors

  • Ameer K. Salho State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, 210016, Nanjing, P.R. China; International Joint Laboratory of Advanced Smart Structures and Control, Nanjing University of Aeronautics and Astronautics, 210016, Nanjing, P.R. China
  • Dhafer A. Hamzah Department of Mechanical Engineering, University of Al-Qadisiyah, Al-Qadisiyah 58001, Iraq
  • Ahmed M. Hassan Department of Mechanical Engineering, University of Al-Qadisiyah, Al-Qadisiyah 58001, Iraq
  • Qasim Mezher Turki Department of Materials Engineering, University of Al-Qadisiyah, Al-Qadisiyah 58001, Iraq
Article ID: 417
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DOI:

https://doi.org/10.18686/cest417

Keywords:

liquid interface; swirl generation; off-center stirred tank; energy dissipation

Abstract

Stirred tanks play a pivotal role in both mechanical and chemical processes. The current study delves into its dynamics through the experimental and numerical study of the vortex shape, vortex size, and depth experimentally and numerically using the finite volume method. Two types of impellers pitched and wavy blade with different rotational speeds of 150, 250, 350, and 450 RPM were used, location on the depth and density of the vortex, flow patterns, torque values, and the amount of power consumption were observed. Theoretically, the mathematical model liquid volume (VOF) used in order to capture the gas-liquid interface, as well as the numerical model (k-ε) was used to simulate turbulent flow in the stirred tank. The obtained experimental and theoretical results showed good convergence in the values. The results showed the vortex reached the maximum depth reaching the surface of the impeller for the pitched impeller at rotation speed 450RPM, followed by the wavy impeller, where the depth of the vortexes is relatively less. In the second case, with the eccentric stirred tank, the shape and location of the vortex formation were different and less intense than in the un-baffled stirred tank. As for the amount of power consumption, the wavy impeller achieved a 40.5% reduction (1.932 W) compared to the pitched blade impeller (3.251 W) at Reynolds number 1.077×10⁵, with vortex depths of 142 mm and 185 mm, respectively, at 450 RPM. Turbulent kinetic energy analysis revealed 28.9% lower values for the wavy impeller (0.096 J/kg) compared to the pitched blade (0.135 J/kg).

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Published

2025-11-05

How to Cite

Salho, A. K., Hamzah, D. A., Hassan , A. M., & Turki, Q. M. (2025). Experimental comparison of wavy and pitched blade impellers for vortex suppression in un-baffled stirred tanks. Clean Energy Science and Technology, 3(4), 417. https://doi.org/10.18686/cest417

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Vol. 3 No. 4 (2025)

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Article

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Copyright (c) 2025 Author(s)

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This work is licensed under a Creative Commons Attribution 4.0 International License.

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