Aeroacoustic evaluation of the forward-curved fan inlet flow
* Presenting author
Forward-curved fans have been extensively used in various industrial and residential HVAC applications. Regarding their favourable characteristic properties, low noise emissions and small size, forward-curved fans have found use in various applications with requirement for high flow rates at moderate pressures and efficiency not being of primary importance. Design of the fan’s inlet flow channel is heavily influenced by limited space available, which results in adverse flow aerodynamics. One of the main reasons for poor efficiency of the forward-curved fan is the flow separation, which starts at the inlet, develops into the blade area and then into the volute. Such vortical flow occupies about a third of the rotor’s width, resulting in a significant flow rate and efficiency reduction. Local measurements of flow velocity using hot wire anemometry were performed and a novelty approach with psychoacoustic metrics adopted to velocity signal processing was used to improve the understanding of the aerodynamic phenomena in the inlet area. The findings exhibit distinct areas and properties of adverse vortical flow and are used in the further inlet channel design process.