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Newsletter  2016.11  Index

Theme : "Mechanical Engineering Congress, 2016 Japan (MECJ-16)"

  1. Preface
  2. Counter-Rotating Type Turbo-Unit Leaving to Markets
    Toshiaki KANEMOTO (Saga University)
  3. Characteristics of Non-equilibrium Grid Turbulence and Scalar Transfer Mechanism
    Yasuhiko SAKAI, Koji Nagata, Yasumasa Ito, Tomoaki Watanabe, Koji Iwano (Nagoya University)
  4. New developments in study of complex fluids
    Takehiro YAMAMOTO (Osaka Electro-Communication University), Takatsune NARUMI (Niigata University), Shigeomi CHONO (Kochi University of Technology)
  5. Bio-related-particle suspensions as complex fluids
    Takehiro YAMAMOTO (Osaka Electro-Communication University)
  6. Energy transfer and drag reduction in the fluid diluted with non-affine polymers
    Kiyosi HORIUTI (Tokyo Institute of Technology)
  7. EFD workshop: optical measurement technique in fluid dynamics
    Masaki FUCHIWAKI (Kyushu Institute of Technology), Shouichiro IIO (Shinshu University), Ayumu  INASAWA (Tokyo Metropolitan University), Satoshi KIKUCHI (Gifu University)
  8. Instantaneous 3D-CT(Computer Tomography) measurements with instantaneous multi-directional photography for unsteady flame/flow phenomena; and 3D printing of 3D reconstructed distributions
    Yojiro ISHINO (Nagoya Institute of Technology)
  9. Simultaneous Measurement of Velocity and Heat Transfer in Unsteady Flow and Thermal Fields near the Wall Region
    Shunsuke YAMADA, Hajime NAKAMURA (National Defense Academy)


Counter-Rotating Type Turbo-Unit Leaving to Markets

Saga University



A unique idea “counter-rotating type turbo-unit” came into Kyushu Institute of Technology on January 25, 1998.  In the unit, tandem impellers/runners connect directly to inner and outer armatures of a peculiar motor/generator.  Both impeller speeds are automatically adjusted in response to the pumping discharge, while the rotational torques between both impellers/armatures are counter-balanced.  That is, the angular momentum change through the rear impeller must coincide with that through the front impeller.  Such adjustments contribute to suppress not only the unstable operation at the lower discharge but also the cavitation at the higher discharge, while the relative rotational speed is kept constant in an induction motor.  The relative rotational speed between the tandem runners, in the generating mode, is higher than the traditional type single runner/armature speed.  Such power units have promising advantages, for instance, (i) the induced voltage is higher at the same diameter, (ii) the diameter of the armature can be reduced at the same individual rotational speed, and then (iii) the rotational moments hardly act on the mounting bed.  The counter-rotation, whose advantages were verified experimentally in the pumping and the generating modes, has been also applied to wind power units, tidal power units.  These units are on stand-to work in the markets.


Key words

Turbomachine, Counter-Rotation, Pump, Turbine, Hydropower, Wind Power,Tidal Power



Fig. 1 Rotational torque acting on the armatures

Fig. 2 Operation in the field

Fig. 3 Performance of the model hydroelectric unit

Fig.4 Intelligent Wind Power Unit

Fig.5 Tidal stream power unit moored with a cable

Last update: 11.2.2016