On the theoretical link between design parameters and performance in cross-flow fans: a numerical and experimental study

Cross-flow fan performance strictly depends on the complex configuration of the non-axisymmetrical flow field within the machine. The flow field, in turn, is deeply influenced by the design parameters of both casing and impeller geometry. In this paper, the relationship between the design parameters of the geometrical configuration and fan performance is discussed in a theoretical perspective, analyzing the features of the corresponding flow fields. These are reconstructed by a numerical study on cross-flow fan operation carried out for a representative set of configurations at different throttling conditions. Time-accurate solutions for a two-dimensional viscous and incompressible model of the fan using a sliding mesh technique are calculated with a commercial CFD code. The numerical results are validated with experimental data obtained from tests on performance and from local measurements of the flow field.