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GUO Qiang
ZHU Xiaocheng
DU Zhaohui
School of Mechanical Engineering, Shanghai Jiaotong University,
Shanghai 200030, China
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EXPERIMENTAL INVESTIGATION
OF TIP CLEARANCE FLOW FOR
AN AXIAL FLOW FAN ROTOR*
Abstract:
The flow field in the tip region of an axial ventilation fan is investigated with a particle image velocimeter (PIV) system at the design condition. Flow fields with three different tip clearances are surveyed on three different circumferential planes, respectively. The phase-locked average method is used to investigate the generation and the development of a tip leakage vortex. The result from PIV system is compared with that from a particle dynamics anemometer(PDA) system. Both data are in good agreement and the structure of the tip leakage vortex for the rotor is illustrated. The characteris-tic of a leakage vortex is described in both velocity vectors and vortical contours. The unsteadiness of the leakage vortex and the position of the vortex are surveyed in detail, which interprets the discrep-ancy between the numerical simulation and PDA experimental results to a certain extent. The center loci of tip leakage vortex at different times and the mean center loci of the leakage vortex are dis-played particularly. Finally, the trajectories of the tip leakage vortex by the experimental measurement are compared with predictions from the existing models for high speed and high-pressure compressors and turbines when appropriately interpreted. A good agreement is obtained.
Key words:
Axial ventilation fan Tip leakage vortex Particle image velocimetry (PIV) Vortex center trajectory
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