放射状すきま流れを用いた低騒音減圧機構に関する研究

抄録

This research proposed using the slit structure instead of the orifice structure to reduce the noise level in the pressure reducing system. The slit structure is comprised of disks similar to a cylinder that has been sliced. The compressed air enters the center of the disk and is exhausted through the slit. Because the pressure reducing is performed by the smooth flow in the slit, this can be performed quietly without causing turbulence flow or generating a shock wave. Parallel and radial type slits were manufactured. The pressure, velocity, and temperature were analyzed,and the silence effect was examined. The results obtained are summarized as follows: (1) In the radial type, the exit average velocity and Reynolds number were lower than the parallel type at the same inlet pressure. (2) The slit structure has the silence effect about 35dB more than an orifice. When the inlet pressure is more than 250KPa, the parallel type has the silence effect about 33dB and the radial type has the silence effect of about 39dB. By the above, the silence effect of the radial type is higher than the parallel type by about 6dB. (3) As a result of the frequency analysis of the noise level of the orifice and the radial types, the drop of the sound pressure level at high frequencies is remarkable.