Effects of the tip clearance on vortical flow and its relation to noise in an axial flow fan

Choon Man Jang, Tohru Fukano, Masato Furukawa

Research output: Contribution to journalArticlepeer-review

45 Citations (Scopus)


Three-dimensional vortical flow structures and velocity fluctuation near the rotor tip in an axial flow fan having two different tip clearances have been investigated by experimental analysis using a rotating hot wire probe and a numerical simulation. It is found that a tip leakage vortex is observed in the blade passage, which has a major role near the rotor tip. The tip leakage vortex formed close to the leading edge of the blade tip on suction side grows in the streamwise direction, and forms a local recirculation region resulting from a vortex breakdown inside the blade passage. The recirculation region is enlarged by increasing the tip clearance. The larger recirculation region induces the acceleration of the through flow, thus resulting in the increase of the broadband noise. High velocity fluctuation is observed at the interference region between the tip leakage vortex and the through flow in the flow field where the tip leakage vortex is tightly rolled up without its breakdown. Near the casing wall, a discrete frequency is formed between tip leakage vortex core and rotor trailing edge.

Original languageEnglish
Pages (from-to)356-365
Number of pages10
JournalJSME International Journal, Series B: Fluids and Thermal Engineering
Issue number3
Publication statusPublished - Aug 2003

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering
  • Physical and Theoretical Chemistry
  • Fluid Flow and Transfer Processes


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