Centrifugal compressor, impeller and operating method of the same

摘要

It is an object of the prevent invention to provide a centrifugal compressor equipped with an impeller having a blade angle distribution that makes it possible to achieve a relatively wide operating range. In a centrifugal compressor, assuming that a blade angle of a shroud side facing a circular plate of a blade is a first angle and a blade angle of a hub side disposed at the circular plate is a second angle, the shroud side is formed in a curved shape having an angle distribution from a front area in a shaft direction toward a centrifugal direction in which the first angle is the local maximum point before a substantially middle portion and the local minimum point after the substantially middle point, and the hub side is formed in a curved shape having an angle distribution from the front area in the shaft direction toward the centrifugal direction in which the second angle is the maximum local point before the substantially middle portion.