Centrifugal compressor and manufacturing method thereof

摘要

A centrifugal compressor includes an impeller, a casing, an impeller housing portion, an inlet port, an annular flow passage provided around the impeller, a discharge port communicated with the annular flow passage, an annular chamber provided around the inlet port, a downstream slot communicating a downstream end of the annular chamber with the impeller housing portion, and an upstream slot communicating an upstream end of the annular chamber with the inlet port. The downstream slot draws a one-cycle curved line pulsating in an axial direction of the inlet port. A most upstream point of the downstream slot is located at an upstream end portion of impeller blades of the impeller when seen along a direction perpendicular to a rotary shaft of the impeller. According to the centrifugal compressor, it becomes possible to expand its operating range by improving a surging restriction effect brought by more effective casing treatment.

主权项

1. A centrifugal compressor that includes an impeller and a casing, the compressor comprising:
an impeller housing portion provided in the casing to house the impeller; an inlet port provided in the casing coaxially with the impeller housed in the impeller housing portion; an annular flow passage provided in the casing so as to surround the impeller housed in the impeller housing portion; a discharge port provided in the casing so as to communicate with the annular flow passage; an annular chamber provided around the inlet port; a downstream slot that communicates a downstream end of the annular chamber with the impeller housing portion; and an upstream slot that communicates an upstream end of the annular chamber with the inlet port, wherein the axial position of the downstream slot varies along the circumference of the inlet port according to a curved line with one single cycle around the circumference and with a predetermined amplitude, the centrifugal compressor being characterised by a most upstream point on a center line of the downstream slot being located at an upstream end portion of impeller blades of the impeller when seen along a direction perpendicular to a direction of a rotary shaft of the impeller.