Compressor with offset diffuser for integral bleed

A compressor system comprising:

• a compressor with a housing defining a compressor chamber;
• an impeller having an outer periphery and disposed to rotate in the compressor chamber, the impeller configured to move a fluid away from its outer periphery;
• a diffuser extending around the impeller and configured to collect the fluid leaving the outer periphery of the impeller;
• an exit through which a main flow of the fluid is discharged from the diffuser, the exit providing an opening that extends circumferentially around the compressor;
• a bleed annulus extending around the compressor in an annular shape and having a consistent cross-sectional area for circumferential flow of the fluid around the compressor;
• and
• a bleed port that opens the diffuser to the bleed annulus and that is configured to divert a bleed flow of the fluid from the main flow before discharge of the main flow through the exit, the bleed port having a circumference around the compressor and a flow size that varies around the circumference;
• wherein variation in the flow size of the bleed port is configured to maintain a uniform flow distribution around the exit.

A compressor system with a compressor for supplying combustion air to the combustor of an auxiliary power unit of an aircraft comprising:

• a housing defining a compressor chamber;
• an impeller disposed to rotate in the compressor chamber, the impeller having a discharge area defined by its outer periphery;
• a diffuser extending around the outer periphery to collect gas leaving the discharge area of the impeller;
• an annular exit through which the gas is discharged from the diffuser to the combustor;
• a bleed annulus extending around the compressor and having a consistent cross-sectional area around the compressor;
• a bleed port that opens the diffuser to the bleed annulus to divert gas from the diffuser before discharge through the annular exit, the bleed port having a circumference around the compressor and a flow size that varies around the circumference;
• and
• a bleed scoop receiving gas from the bleed annulus that is diverted from the diffuser through the bleed port;
• wherein variation in the flow size of the bleed port maintains a consistent, uniform flow distribution around the annular exit to the combustor.