Silencer for reducing acoustic noise of fuel cell system
A silencer installed in a fuel cell system includes a plurality of expansion chambers connected to a predetermined apparatus of the fuel cell system, wherein the plurality of expansion chambers serially reduces acoustic noise of air discharged from the predetermined apparatus and a resonator connected to an expansion chamber of the plurality of expansion chambers, wherein the resonator reduces acoustic noise received from the expansion chamber in another frequency band, which is different from a frequency band of the acoustic noise reduced by the plurality of expansion chambers, where one of the plurality of expansion chambers comprises an inlet pipe which receives air from the predetermined apparatus, another of the plurality of expansion chambers comprises an outlet pipe which discharges air flowed into the plurality of expansion chambers, and an intermediate pipe is disposed between the plurality of expansion chambers.
1. A silencer installed in a fuel cell system, the silencer comprising:
a plurality of expansion chambers connected to a predetermined apparatus of the fuel cell system, wherein the plurality of expansion chambers serially reduces acoustic noise of air discharged from the predetermined apparatus; and
a resonator connected to an expansion chamber of the plurality of expansion chambers, wherein the resonator reduces acoustic noise received from the expansion chamber in another frequency band, which is different from a frequency band of the acoustic noise reduced by the plurality of expansion chambers,
wherein one of the plurality of expansion chambers comprises an inlet pipe which receives air from the predetermined apparatus,
wherein another of the plurality of expansion chambers comprises an outlet pipe which discharges air flowed into the plurality of expansion chambers, and
wherein an intermediate pipe is disposed between the plurality of expansion chambers.
2. The silencer of claim 1 , wherein
the plurality of expansion chambers and a cavity of the resonator are defined by a plurality of partitions which divides an inner space of the silencer.
3. The silencer of claim 2 , wherein
a cavity of a first resonator of the resonator shares the plurality of partitions with a first group of the plurality of expansion chambers,
a cavity of a second resonator of the resonator shares the plurality of partitions with a second group of the plurality of expansion chambers, and
a number of the plurality of expansion chambers in the second group is greater than a number of at least one expansion chamber in the first group.
4. The silencer of claim 1 , wherein a number of the plurality of partitions is substantially proportional to a sum of a number of the plurality of expansion chambers and a number of the cavity of the resonator.
5. The silencer of claim 2 , wherein a volume of the cavity is substantially inversely proportional to a size of a center frequency of the another frequency band.
6. The silencer of claim 2 , wherein
a first intermediate pipe extends through a first partition between a first expansion chamber and a second expansion chamber of the plurality of expansion chambers,
a second intermediate pipe extends through a second partition between the second expansion chamber and a third expansion chamber of the plurality of expansion chambers,
an end of an outlet of the first intermediate pipe is disposed closer to the second partition than an end of an inlet of the second intermediate pipe such that air discharged from the outlet of the first intermediate pipe into the second expansion chamber flows into the inlet of the second intermediate pipe in a backflow form.
7. The silencer of claim 1 , wherein
a neck of the resonator protrudes into the expansion chamber of the plurality of expansion chambers connected to the resonator such that internal air of the expansion chamber connected to the resonator flows into a hole of the neck of the resonator and the air flowed into the hole of the neck of the resonator is discharged into the expansion chamber connected to the resonator from the hole of the neck of the resonator.
8. The silencer of claim 2 , wherein
a length of a neck of the resonator is substantially inversely proportional to a size of a center frequency of the another frequency band which is different from the frequency band of the acoustic noise reduced by the plurality of expansion chambers, and
a size of a cross-section of the neck of the resonator is substantially proportional to the size of the center frequency of the another frequency band which is different from the frequency band of the acoustic noise reduced by the plurality of expansion chambers.
9. The silencer of claim 1 , wherein
the predetermined apparatus is an air pump which supplies air to a fuel cell of the fuel cell system, and
the outlet pipe is connected to an inlet at a cathode of the fuel cell of the fuel cell system such that air discharged from the outlet pipe flows into the inlet at the cathode of the fuel cell.