Session: 10-01 Numerical Simulations and Fan Noise

Paper Number: 121322

121322 - Comparison of Vortex Detection Methods on the Numerical Simulation of Tip Leakage Flow of a Low-Speed Axial Fan 

Low-speed, ducted axial fans are commonly used in household appliances and industrial ventilation as well. In today’s energy crisis, efficiency is a timely issue, thus, any kind of loss reduction for machinery is welcomed. In the case of ducted fans, one prominent loss and noise source is the tip leakage flow. When the tip leakage flow rolls up, it constructs the so-called tip leakage vortex, which will be in the focus of the paper.

The authors have already conducted numerical simulations on a low-speed ducted axial fan in order to investigate the tip leakage flow [1]. The simulations presented the formation of tip leakage vortex and also its wandering motion. The detection of the vortex cores was performed using Banks’ vorticity predictor – pressure corrector vortex core line localization method [2].

In order to further investigate the formed tip leakage vortex,

another vortex detection method is applied, the Lagrangian Averaged Vorticity Detection (LAVD) [3]. The authors have already used the LAVD method to detect the location of the shed vortices in simulations on circular and square cylinders [4]. The usage of the LAVD method in the present case study would extend its utilization to turbomachinery applications. The advantage of the LAVD method compared to Banks’ is that it uses only kinematic quantities, thus is applicable for compressible media, and it may also offer information on the strength of the vortices besides the position of their core.

The results presented in the paper are organized as follows:

a)      Introduction of the LAVD vortex detection method for turbomachinery applications

b)      Presentation of the setup of the numerical simulation for the low-speed axial fan

c)      Comparison of the position of the vortex cores for multiple vortex detection methods

References

[1] Lendvai B., Benedek T.: Application of a Vortex Identification Method for Quantifying the Tip Leakage Vortex Wandering in a Low-Speed Axial Fan Case Study. European Turbomachinery Conference (ETC15) 2023.04.24.-28. (2023)

[2] Banks, D. C., Singer, B. A. (1995) A predictor-corrector technique for visualizing unsteady flow. IEEE Transactions on Visualization and Computer Graphics 1(2), 151–163. doi:10.1109/2945.468404

[3] Haller, G., Hadjighasem, A., Farazmand, M., Huhn, F. “Defining coherent vortices objectively from the vorticity”, Journal of Fluid Mechanics, 795, pp. 136-173, 2016. doi:10.1017/jfm.2016.151

[4] Kovács, K. A., Balla, E. “Parameter Identification of the Lagrangian-averaged Vorticity Deviation Vortex Detection Method Through the Investigation of Fluid Flow Around Solid Bodies”, Periodica Polytechnica Mechanical Engineering, 2023. doi:10.3311/PPme.22874

Presenting Author: Esztella Balla Dept. of Fluid Mechanics, Fact. of Mech. Eng., Budapest University of Tech. and Economics

Presenting Author Biography: Esztella Balla earned her PhD in 2020 from the Budapest University of Technology and Economics. She has been an assistant professor the Department of Fluid Mechanics since then.

Authors:

Esztella Balla Dept. of Fluid Mechanics, Fact. of Mech. Eng., Budapest University of Tech. and Economics
Kinga Andrea Kovács Dept. of Fluid Mechanics, Fact. of Mech. Eng., Budapest University of Tech. and Economics
Bálint Lendvai Dept. of Fluid Mechanics, Fact. of Mech. Eng., Budapest University of Tech. and Economics