The diffuser of a centrifugal compressor having an unshrouded rotor has boundary layer fences on the walls bounding the diffuser in advance of the diffuser vanes. These vanes are directed across the direction of flow of boundary layer air on the diffuser wall and curve into the direction of the diffuser vanes as they merge with the leading edge of the vanes.
A radial flow compressor is described which includes a diffuser having an annular entrance chamber surrounding the circumferential discharge of the impeller of the compressor. Diffuser channels extend from this annular chamber to an axial flow diffuser from which the compressed air is discharged into a collection chamber. The annular chamber is provided with contoured nodes from which the channel diffusers respectively extend at relatively low angles, tangentially in relation to the periphery of the impeller.
A centrifugal compressor has diffusers which convert a high velocity, low pressure stream of fluid which flows out of an impeller to a high-velocity high-pressure flow due to the action of a purality of stator blades disposed near the outer periphery of the impeller. In this compressor, the portion of the stator blade or of an auxiliary blade which is provided in the diffuser located on the side of a front shroud is disposed closer to the impeller than the portion thereof located on the side of a main shroud, and the leading edge of the stator blade is thus inclined from the portion thereof located on the side of the main shroud to the portion thereof located on the side of the front shroud. The configuration of the front edge of a stator blade or of an auxiliary blade which is provided in the diffuser is so improved as to restrict back flow which occurs on the side of the front shroud when the flow rate is small and to lower the minimum flow rate. Furthermore, an auxiliary blade and an intermediate blade are disposed between the adjacent stator blades, and the leading edge of the auxiliary blade is so improved as to enlarge the operation range of the diffuser and to improve volume control greatly.
A centrifugal compressor has a diffuser with stator blades arranged therein for converting the kinetic energy of a fluid discharged from an impeller into a pressure energy. The stator blades have leading edges inclined in the downstream direction while extending away from a side plate toward a core plate. Auxiliary blades having a chord length shorter than that of each of the stator blades have leading edges inclined in the downstream direction while extending away from the side plate toward the core plate and are arranged at positions radially inward of the stator plates in such a manner that one of the surfaces of each of the auxiliary blades faces a stator blade. The compressor is capable of operating without suffering from surging and rotating stall even in a low flow rate region.
The improved diffuser includes pinching a portion of a diffuser flow passageway that has ribs therein extending partially across the diffuser passageway and that have their leading edges located away from the inlet of the diffuser passageway. The diffuser passageway is pinched from the diffuser inlet to the leading edge of the ribs to provide improved flow angle alignment and the leading edges of the ribs been moved away from the impeller to avoid buffeting and noise as the compressed gas leaves the impeller and enters the annular diffuser passageway.
