Session: 10-01 Fan Aerodynamic Design

Paper Number: 151471

Effects of Backward-Forward Blade Skew on the Performance of an Axial Flow Fan Designed for Automotive Applications 

Axial fans are conventionally designed assuming cylindrical stream tubes since secondary radial flows inside the machine are usually neglected in the preliminary design phase. This assumption is acceptable in the case of a rotor designed using a free vortex law, FVD, where minimal radial flows are present. However, in the case of a fan designed according to a controlled vortex approach, CVD, the assumption of two-dimensional flows over cylindrical surfaces is not suitable due to the occurrence of non-negligible radial fluid migration. According to the literature, a non-radial stacking law could be used to restore the flow closer to cylindrical flow surfaces. However, when properly applied, the non-radial stacking is not only limited to the control of the flow radial components but it is also useful for the improvement of fan efficiency, stall resistance, and noise emission (both overall level and tonal peaks). The most appropriate stacking law depends on many variables, such as vortex law, rotational speed, flow rate, hub-to-tip ratio, tubed or un-tubed fan, and shrouded or un-shrouded fan. For this reason, no general rules can be found in the literature for applying the stacking law to control the secondary flows and thus improve the performance of a CVD rotor. 

The current work shows a sensitivity analysis of the geometric parameters of a line-arc stacking law on the performance of a CVD axial flow fan. Different circumferential blade skew configurations are simulated using a single-blade channel CFD approach. The results obtained are analyzed using a statistical approach to identify the geometric parameters of the law that most influence the machine's performance.

Presenting Author: Mattia Piovan University of Ferrara

Presenting Author Biography: Graduated in Mechanical Engineering at the University of Ferrara in 2022, since the same year he has been a PhD student in Engineering Sciences at the Department of Engineering of the University of Ferrara.

His research activity is focused on the development of innovative methodologies for predicting and reducing the noise emitted by fans, mainly using an open-source numerical approach. Another topic of interest is the development of design criteria for high-efficiency turbomachinery.

His research activity is collected in scientific articles presented at national and international conferences and published in the sector scientific journals.

Authors:

Mattia Piovan University of Ferrara
Nicola Aldi University of Ferrara
Michele Pinelli University of Ferrara
Alessio Suman University of Ferrara
Nicola Zanini University of Ferrara
Enrico Mollica SPAL Automotive Srl