Patent ID: 8061961

Claim:
A fluid expansion device into which a fluid is adapted to enter at a first pressure, through which the fluid is adapted to flow, and from which the fluid is adapted to exit at a second pressure that is less than the first pressure, the fluid expansion device comprising: a stationary first member comprising an annular section; a stationary second member comprising a ring and defining first and second surfaces; a plurality of stationary blades extending from the second surface of the second member; a plurality of rotary blades extending from a rotatable wheel, the plurality of stationary blades directing the fluid to the plurality of rotary blades to thereby impel the wheel to rotate; and a plurality of first acoustic resonators disposed between adjacent ones of the plurality of stationary blades, each of the plurality of first acoustic resonators comprising: a first opening extending from the first surface defined by the second member, and into the second member; and a plurality of second openings extending from the second surface, and to the first opening; one of the first member and the second member extending circumferentially about the other so that the first member abuts the first surface of the second member and thereby caps an end of the first opening opposing the second openings; wherein one or more of the plurality of first acoustic resonators are sized to attenuate around a frequency of acoustic energy generated as the fluid flows past the plurality of stationary blades.