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

The present paper investigates the capabilities of the Lagrangian-Averaged Vorticity Deviation (LAVD) vortex detection method for turbomachinery applications. The tip leakage vortex of a low-speed axial fan is identified with multiple vortex detection methods. The investigation is carried out on a numerical simulation of a ducted fan. The results from the LAVD method are compared with the outcomes of the following vortex detection techniques: Q criterion, VR helicity density, vortex core distance technique of Li and Carrica, and Banks’ vorticity predictor-pressure corrector vortex core identification method. The position and extension of the vortex region and the location of the vortex core line are considered during the comparison. The results show that the vortex region and core detected by the LAVD technique are in great accordance with the outcome of the other methods. Compared to other methods, the advantage of the LAVD technique is that its parameters can be objectively defined from geometrical features of the flow field, e.g., blade chord length. The LAVD is also able to detect the core and the perimeter of the vortex region.