Investigation of the turbulent swirl flow in pipe generated by axial fans using PIV and LDA methods
In this paper is presented experimental investigation of the turbulent swirl flow in pipe generated by axial fans. Two various models of industrial axial fans are used. One of these is axial fan W30, model AP 400, Minel, Serbia and has seven blades and outer diameter 0.397m. Second axial fa...
Main Authors: | , , |
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Format: | Article |
Language: | English |
Published: |
Serbian Society of Mechanics & Mathematical Institute of the Serbian Academy of Sciences and Arts, Belgrade
2015-01-01
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Series: | Theoretical and Applied Mechanics |
Subjects: | |
Online Access: | http://www.doiserbia.nb.rs/img/doi/1450-5584/2015/1450-55841503211C.pdf |
Summary: | In this paper is presented experimental investigation of the turbulent swirl
flow in pipe generated by axial fans. Two various models of industrial axial
fans are used. One of these is axial fan W30, model AP 400, Minel, Serbia and
has seven blades and outer diameter 0.397m. Second axial fan SP30 is model
TGT/2-400-6, S&P, Spain, has six blades and outer diameter 0.386m. This
results with greater clearance in the second case. Blades were adjusted for
both fans at the angle of 30° at the outer diameter. Test rig length is
27.74-D, where D is average inner diameter app. 0.4 m. Measurements are
performed in two measuring sections downstream the axial fans (z/D = 3.35
and z/D = 26.31) with one-component laser Doppler anemometry (LDA) system and
stereo particle image velocimetry (SPIV). Obtained Reynolds numbers,
calculated on the basis of the average axial velocity (Um) in the first
measuring section are for fan SP30 Re = 226757, while for fan W30 Re =
254010. Integral flow parameters are determined such as average circulation
and swirl number. Significant downstream axial velocity transformation occurs
for both fans, while circumferential velocity is decreased, but
non-dimensional velocity profile remains the same. Circumferential velocity
distribution for both fans in the central zone corresponds to the solid body,
while in r/R > 0.4, where D = 2R, distribution is more uniform. Radial
velocity in the case of fan SP30 has almost zero values in the measuring
section z/D = 3.35, while its values are significantly increased in the
downstream section with the maximum in the vortex core region. On the
contrary radial velocity decreases downstream for fan W30 and has also
maximum value in the vortex core region for both measuring sections. Level of
turbulence, skewness and flatness factors are calculated on the basis of the
experimental data. The highest levels of turbulence for circumferential
velocity are reached in the vortex core region for both fans. It is shown how
statistical moments of the third and fourth order differ from the values for
normal Gaussian distribution. In this paper are also analyzed velocity fields
by use of SPIV. [Projekat Ministarstva nauke Republike Srbije, br. TR 35046] |
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ISSN: | 1450-5584 2406-0925 |