抄録
Fuel cell systems may be regarded as noiseless electric power plants, the reason being that combustion engines are not used. However, small blowers have to run in order to supply fuel gas and air to the cell stack, and this generates noise and vibrations. Small type fuel cell systems for home appliances should be quiet, similar to air conditioning systems for home use. The problem with louder noise and vibrations from a small blower composed with a twin-screw rotor arose in the first version of developing this small blower. Non-contacting sensing of vibrations in the blower casing and the rotors was examined with the laser doppler vibrometer to clarify the mechanism of the vibrations. Also, a numerical analysis of the vibration characteristics of the blower was executed by FEM. It was recognized that the electromagnetic fluctuating force induced by the motor excited the natural vibration mode of the twin rotor. Optimizing the magnetic intensity of the magnetic coupling in order to smooth the fluctuating force and adapt a damping effect in the rotors was attempted to improve the large vibration mechanism. Finally, we achieved permissible quietness and low vibration levels radiated from the improved small blower.
