Airfoil selector for fan applications: a multi-fidelity investigation

Energy saving is one of the most important milestones of the energy-green transition, for this reason, the fans’ consumers are very interested in upgrading the efficiency and in general, the performance of their products to comply with increasingly strict standards. To do that different strategies can be used, the one proposed inside the work is based on the redesign of the fan’s swirl adjuster blades to increase efficiency reducing the flow losses. An in-house tool, using a low-fidelity approach, is developed to select the best airfoil shape for prescribed flow conditions. The airfoil shape can be selected over a wide range of standard airfoils, i.e. NACA, Nrel, and Gottingen. The baseline swirl adjuster is realized with the same airfoil shape for all the considered stream-tube, while the optimal swirl adjuster has different airfoils for each flow tube, each with a significant increase in lift/drag ratio compared to the original airfoils. To validate the results obtained with the low-fidelity tool the new swirl adjuster is therefore simulated through CFD, which is considered the high-fidelity tool. The effects of the optimization are shown by comparing both the swirl adjuster pressure drop and the flow morphology inside the device.