12th European Conference on Turbomachinery Fluid dynamics & Thermodynamics
Authors
Abstract
Rotor-only axial fans feature rotors designed according to different vortex criteria. Nowadays the literature does not exhaustively clarify when a specific swirl distribution has to be used and which are the advantages/drawbacks in terms of fan performance and efficiency. A review of the experimental performance of rotor-only axial fans designed with different vortex criteria is summarized here in Φ-Ψ and σ-δ (specific speed - specific diameter) graphs to identify the best operating conditions of each design. Four rotor-only axial fans (two free-vortex, a constant-swirl and a rigid-body swirl one) are tested on an ISO-5801-A rig. For two of them, flow velocities at rotor exit are measured with a 5-hole probe. The result is an experimentally based map around the Cordier curve for rotor-only axial fans. Indications on the best Φ-Ψ range for fans designed using different vortex criteria are provided and explained. The effects of increasing the tip clearance on the rotor performance at design duty are investigated as well.
ETC2017-055
Paper is available for download