Towards an Accurate Aerodynamic Performance Analysis Methodology of Cross-Flow Fans

Abstract

Cross-flow fans (CFFs) have become increasingly popular in recent years. This is due to their use in several domains such as air conditioning and aircraft propulsion. They also show their utility in the ventilation system of hybrid electric cars. Their high efficiency and performance significantly rely on the design parameters. Up to now, there is no general approach that predicts the CFFs’ performance. This work describes a new methodology that helps deduce the performance of CFFs in turbomachinery, using both analytical modeling and experimental data. Two different loss models are detailed and compared to determine the performance–pressure curves of this type of fan. The efficiency evaluation is achieved by realizing a multidisciplinary study, computational fluid dynamics (CFD) simulations, and an optimization algorithm combined to explore the internal flow field and obtain additional information about the eccentric vortex, to finally obtain the ultimate formulation of the Eck/Laing CFF efficiency, which is validated by the experimental results with good agreement. This approach can be an efficient tool to speed up the cross-flow fans’ design cycle and to predict their global performance.

Application of Digital Twins and Metaverse in the Field of Fluid Machinery Pumps and Fans: A Review

“…The formula for the efficiency of the Eck/Laing cross-flow fan was obtained, and the experimental results were well verified, thereby achieving efficiency evaluation. Hence, the proposed method could effectively speed up the design cycle of cross-flow fans and predict their global performance [ 98 ].…”

Control of Aerodynamic Characteristics of Thick Airfoils at Low Reynolds Numbers Using Methods of Boundary Layer Control

“…The increased pressure in the section of the airfoil from the slot to the blowing nozzle creates positive thrust. The CFF efficiency reaches about 80%, which is lower than that of axial fans, but this is compensated by the convenience of the design, less sensitivity to flow inhomogeneity in the boundary layer, and large back pressure [13]. When the boundary layer is blown off, air can be extracted from the high-pressure region at the bottom of the wing, and the CFF will play the role of an energy flap [25].…”

“…Without air extraction, such airfoils have poor streamlining, while with the required air flow through the internal channel, the tail section of the airfoil generates thrust. The procedure for air extraction is technically executed through a transverse (tangential) fan (crossflow fan or CFF) [11][12][13]. By altering the fan blade rotation speed, separation of the boundary layer can be avoided [4].…”

Control of Aerodynamic Characteristics of Thick Airfoils at Low Reynolds Numbers Using Energy Methods

“…tail section of the airfoil creates thrust. The technical implementation of air extraction is carried out using a transverse (tangential) fan (Cross Flow Fan, CFF) [6][7][8]. Changing the rotation speed of the fan blades prevents separation of the boundary layer [9].…”