Affiliations: Department of Mechanical Engineering, Pohang
University of Science and Technology, Pohang 790-784, Korea. | Digital Appliance Research Laboratory, LG Electronics,
Seoul 153-023, Korea.
Abstract: The flow characteristics around a rotating axial fan were
experimentally investigated using a phase-averaged PTV velocity field
measurement technique. The axial fan has 5 forward-swept blades with a radius
of 25 mm. Measurements were carried out at 4 axial planes and 4 radial planes
perpendicular to the axis of rotation. For the axial plane measurements, one
fan blade was divided into 4 different phases in order to analyze the flow
structure according to blade phase. For each case, 500 instantaneous velocity
fields were measured and ensemble averaged to obtain phase-averaged velocity
vector fields and vorticity contours. In addition, measurements were carried
out at two planes around the blade surface. Phase averaged velocity fields show
periodic variations with respect to the blade phase. The periodic shedding of
the tip vortex at the blade tip is also observed. The phase averaged velocity
fields measured in the radial planes show periodic variations according to the
fan phase and the distance from the fan. These experimental results can be used
to validate numerical calculations and to understand the flow characteristics
of forward-swept axial fans.