International Journal of Fluid Machinery and Systems

Korean Society for Fluid machinery (한국유체기계학회)
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Experimental Study and Numerical Simulation of Cavity Oscillation in a Conical Diffuser

  • Chen, Chang-Kun (Graduate School of Engineering Science, Osaka University) ;
  • Nicolet, Christophe (Laboratory for Hydraulic Machines, EPFL - Swiss Federal Institute of Technology) ;
  • Yonezawa, Koichi (Graduate School of Engineering Science, Osaka University) ;
  • Farhat, Mohamed (Laboratory for Hydraulic Machines, EPFL - Swiss Federal Institute of Technology) ;
  • Avellan, Francois (Laboratory for Hydraulic Machines, EPFL - Swiss Federal Institute of Technology) ;
  • Miyazawa, Kazuyoshi (Nagasaki R&D Center, Mitsubishi Heavy Industries, LTD) ;
  • Tsujimoto, Yoshinobu (Laboratory for Hydraulic Machines, EPFL - Swiss Federal Institute of Technology)
  • Received : 2010.03.19
  • Accepted : 2010.03.24
  • Published : 2010.03.01
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Abstract

Based on the one-dimensional stability analysis, the self-excited oscillation in hydraulic power generating systems was studied by a simple experiment and numerical simulation. It was shown that a cavity in a conical diffuser can cause surge. With the diffuser, a high amplitude and low frequency oscillation occurs at low cavitation number. This oscillation was not observed with the straight pipe. It was confirmed that the diffuser effect of the draft tube can be the cause of the full load surge in hydraulic power system. Numerical results were also analyzed to check the validity of the one-dimensional stability analysis.

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References

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