1. Technical Field
The present disclosure relates to a centrifugal compressor of the like that compresses fluid such as air using centrifugal force.
2. Description of the Related Art
In recent years, various types of research and development have been made on centrifugal compressors used in turbochargers, gas turbines, industrial pneumatic devices and the like.
A general centrifugal compressor includes a compressor housing. The compressor housing has a shroud inside. A compressor wheel is rotatably provided around the center axis thereof in the compressor housing. The compressor wheel includes a hub (compressor disk). The hub has a hub surface extending outward in the radial direction (in the radial direction of the compressor wheel) from one axial side (one axial side of the compressor wheel). Furthermore, the hub surface has plural compressor blades integrally provided thereon at intervals in the circumferential direction. Each of the compressor blades has a distal end edge extending along the shroud of the compressor housing.
A fluid inlet port (fluid inlet flow passage) for taking in fluid such as air into the compressor housing is formed on the inlet side (upstream side) of the compressor wheel in the compressor housing. Furthermore, a ring-shaped diffuser (diffuser flow passage) that decelerates compressed fluid (compressed fluid such as compressed air) to increase its pressures is formed on the outlet side (downstream side) of the compressor wheel in the compressor housing. In addition, the diffuser having a high static-pressure recovery property usually has a ring-shaped parallel part, and a ring-shaped throttling part formed continuously to the inside of the parallel part in the radial direction. In the parallel part, a wall surface located on the shroud side and a wall surface located on the hub side are provided so as to be in parallel to the radial direction. On the other hand, in the throttling part, a wall surface located on the shroud side gradually approaches a wall surface located on the hub side toward the outside in the radial direction.
A compressor scroll (compressor scrolling flow passage) having a spiral shape is formed on the outlet side of the diffuser within the compressor housing to communicate with the diffuser. Furthermore, a fluid discharge port (fluid discharge flow passage) for discharging the compressed fluid to the outside of the compressor housing is formed at an appropriate position within the compressor housing to communicate with the compressor scroll.
In addition, conventional arts related to the present disclosure are described in Japanese Patent Laid-Open Publication Nos. 2013-199941 and 2007-309169, and Japanese Patent No. 5050511.