Ported shroud system for turboprop inlets

A system for delivering a flow stream of a gas, comprising:

• a compressor configured to receive the gas and to increase a pressure of the gas, the compressor including an impeller rotatable about an axis;
• a shroud extending from an inlet that is open to atmosphere to the compressor at a location around the impeller, the shroud defining, at least in part:
• a main inlet passage configured to direct the gas from the inlet to the compressor, the main inlet passage transitioning from a first shape at the inlet to a second shape at the compressor that differs substantially from the first shape, the main inlet passage including a first section adjacent the inlet, the first section having a smile shape at the inlet and the main inlet passage transitioning from the first section to a second section adjacent the compressor and around the impeller of the compressor, the second section having an annulus shape;
• a communication plenum separated from the main inlet passage;
• and
• a port system that includes first and second port subsystems each providing an opening between the main inlet passage and the communication plenum, the first port subsystem disposed further from the compressor than the second port subsystem, the first port subsystem disposed in the first section and the second port subsystem disposed in the second section;
• wherein the port system is configured so that a portion of the gas enters the plenum from the main inlet passage through the second port subsystem and exits the plenum to the main inlet passage through the first port subsystem when the compressor has an excess of the gas, and the port system is configured so that alternatively, a portion of the gas enters the plenum from the main inlet passage through the first port subsystem and exits the plenum to the main inlet passage through the second port subsystem when the compressor has a deficiency of the gas.

A system for delivering a flow stream of gas in an engine, comprising:

• a compressor configured to receive the gas and to increase a pressure of the gas directed into the engine, the compressor including an impeller that is rotatable about an axis;
• a shroud extending from an inlet that is open to atmosphere to the compressor at a location around the impeller, the shroud defining, at least in part:
• a main inlet passage configured to direct the gas from the inlet to the compressor, the main inlet passage transitioning from a first shape at the inlet to a second shape at the compressor that differs substantially from the first shape;
• a communication plenum separated from the main inlet passage;
• and
• a port system with first and second port subsystems, the first port subsystem providing a first opening between a first point of the main inlet passage and the communication plenum, the second port subsystem providing a second opening between a second point of the main inlet passage and the communication plenum, the first point configured with a higher pressure in the flow stream than the second point and the first port subsystem disposed further from the compressor than the second port subsystem;
• wherein the shroud defines an anti-ice passage configured to circulate a heated gas, wherein the first and second port subsystems extend through the anti-ice passage, wherein each of the openings of the first and second port subsystems is surrounded by a wall when extending through the anti-ice passage;
• wherein the port system is configured so that a portion of the gas enters the plenum from the main inlet passage through the second port subsystem and exits the plenum to the main inlet passage through the first port subsystem to inhibit stall of the compressor when the compressor has an excess of the gas, and the port system is configured so that alternatively, a portion of the gas enters the plenum from the main inlet passage through the first port subsystem and exits the plenum to the main inlet passage through the second port subsystem to increase power output from the compressor when the compressor has a deficiency of the gas.