Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.
Cross Flow Fans (CFFs) are used in air
conditioning and ventilation technology because of their
compact design and low noise. In addition, CFFs can
provide a uniform velocity profile along the width of the
fan. This offers an enormous advantage in applications
with large width to diameter ratios as needed. However,
as the flow pattern inside a CFF is very complex,
classical fan design is not applicable. At present, the
design of CFFs is most often based on experimental
investigation and empirical experience. In order to
investigate the behaviour of these type of fans and its
relation to the complex flow structure inside casing and
rotor, CFD-simulations are carried out. In this study,
transient solutions for a two dimensional viscous and
incompressible model of the fan are used to assess the
cross flow fan with two parallel outlets. The impact of
the outlet configuration on the flow patterns is thereby
numerically investigated. It is shown that both the
diffuser and the position of the vortex wall play a crucial
role to achieve stable and balanced volumetric flows
through the two outlets.
