Patent ID: 8465251

Claim:
A compressor device comprising: a plurality of blades on an impeller rotated about a rotation axis; an air inlet extending along the rotation axis and introducing air to the blades; a circulating channel disposed on a circumference of the air inlet and centered on the rotation axis of the impeller and communicating between the air inlet and a shroud of the blades; and a strut extending radially centered on the rotation axis and dividing the circulating channel; wherein resonance frequencies determined from circumferential lengths in the circulating channels divided by the strut are higher than a noise frequency determined from a rotational speed of the blades and the number of blades, and wherein the circumferential length L of the circulating channel is shorter than a value expressed by the following equation: L= 60 c 1 ×C /( NZ ), where c1 is a coefficient determined by a shape of the circulating channel, C is the velocity of sound, N is a rotation speed of the blades, and Z is a number of blades.