| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1994: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1993: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
In rotating machinery, it is generally found that exciting torque occurs at the same frequency as the rotating speed or at multiples of the rotating speed. An untuned vibration damper. such as the Lancaster damber, is frequently used to reduce torsional vibrations. However, it is not as effective as a dynamic absorber. If an attached dynamic absorber has the same natural frequency as the exciting frequency, vibration is suppressed. A centrifugal pendulum vibration absorber effectively eliminates torsional vibrations if it is well tuned. However, it sometimes does not operate satisfactorily due to friction or insufficient adjustment.
We have shown experimentally that torsional vibrations can be suppressed by attaching a hollow cylinder partially filled with liquid. The hollow cylinder is sectored into identical chambers by radial walls. Tuning conditions, such as the amount of water, the height of chambers and the number of sectors, were examined. The perturbation solution based on the t
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heory for inviscid liquid disregarding the Coriolis acceleration terms shows poor agreement with experiment.
An The experimental and theoretical study is performed on suppression of torsional vibrations of a rotor by attaching a hollow cylinder partially filled with liquid. The hollow cylinder is divided into identical sectors by radial walls. In addition to measuring torsional vibration, surface waves were photographed to observe the motion of the contained liquid. The number of divisions of tested hollow cylinders is 2,3,4,6 and 8. The tuning conditions for fill rations are also examined. Experimental results show that the surface waves move backward, that is, travel in the direction opposite the rotation. Analysis including the Coriolis acceleration terms is presented. Analytical results show good agreement with the experimental ones whereas the analysis without Coriolis terms shows poor agreement. Accordingly, the surface wave motion is not stationary due to the Coriolis force which acts while the liquid moves. Less
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