Centrifugal turbomachines having extended performance ranges

A method of extending the performance-range of a centrifugal compressor of a combustion-gas-charging system of an internal combustion engine (ICE) system, the ICE system including combustion gas systems and exhaust gas systems, the centrifugal compressor including:

• an impeller rotatable about a rotational axis and having:
• an inlet region located proximate to the rotational axis;
• an outlet region located distal from the rotational axis;
• and
• a plurality of blades extending between the inlet and outlet regions;
• and
• a casing circumferentially enshrouding the impeller so as to define a blade-tip-clearance gap between the casing and the plurality of blades, the casing including a high-momentum-flow injector located upstream of the blade-tip clearance gap;
• the method comprising:
• injecting a high-momentum flow from a location in said ICE system downstream of said outlet region of said impeller through the high-momentum-flow injector in a direction of flow of a working fluid in the compressor so as to reenergize flow within the blade-tip-clearance gap;
• and
• prior to said injecting, cooling the high-momentum flow.

A system, comprising:

• an internal combustion engine having combustion-gas intake and an exhaust-gas outlet;
• a forced-induction system designed and configured to provide a combustion gas to said internal combustion engine, said forced-induction system including a centrifugal compressor having an inlet region;
• an exhaust-gas-recirculation system designed and configured to provide a portion of an exhaust gas from said exhaust-gas outlet to said combustion-gas intake;
• and
• at least one flow injector fluidly connecting said exhaust-gas recirculation system to said inlet region of said centrifugal compressor and designed and configured to provide a flow of at least some of the exhaust gas to said inlet region of said centrifugal compressor;
• said inlet region including a primary flow region for receiving a first portion of the combustion gas, a secondary flow region located radially outward from said primary flow region, said secondary flow region for receiving a second portion of the combustion gas, and a flow partition separating said secondary flow region from said primary flow region, wherein said flow partition is located so that the second portion of the combustion gas is joined with the first portion of the combustion gas downstream of the flow partition.

An apparatus comprising:

• a centrifugal turbomachine that includes:
• a casing having a wall and defining an intake and a throat region, said wall transitioning in said throat region from a larger cross-sectional flow area upstream of said throat region to a smaller cross-sectional area downstream of said throat region;
• an impeller disposed in said casing and rotatable about a rotational axis and having:
• an impeller inlet and outlet;
• an impeller hub;
• and
• a plurality of impeller blades extending between said impeller inlet and outlet and extending from said impeller hub to a location adjacent said casing wall;
• and
• an inducer disposed in said casing and rotatable about said rotational axis, said inducer having a partial shroud;
• said intake having a primary flow region located radially inward of said partial shroud and a secondary flow region located radially outward of said partial shroud;
• and
• a performance-range-enhancing treatment applied to said intake and designed and configured to enhance the performance range of said centrifugal turbomachine, wherein said performance-range-enhancing treatment includes a flow modulator located in said secondary flow region upstream of said inducer, said flow modulator being designed and configured to modulate flow of a working fluid in said secondary flow region.

A method of extending the performance-range of a centrifugal turbomachine, the turbomachine including:

• an impeller rotatable about a rotational axis;
• an inducer located upstream of the impeller and rotatable about the rotational axis, the inducer having a partial shroud and partially defining a primary flow region located radially inward of the partial shroud and a secondary flow region located radially outward of the partial shroud;
• a flow modulator located upstream of the inducer and located in the secondary flow region, the flow modulator designed and configured to modulate flow in the secondary flow region;
• and
• an inlet region upstream of the impeller, and an outlet region downstream of the impeller;
• the method comprising:
• monitoring a flow rate of a working fluid entering the centrifugal turbomachine;
• during times of relatively low flow of the working fluid into the centrifugal turbomachine, closing the flow modulator, thereby directing substantially all of the working fluid to the inlet region of the centrifugal turbomachine through the primary flow region;
• and
• during times of relatively high flow of the working fluid into the centrifugal turbomachine, opening the flow modulator to increase a throat area of the centrifugal turbomachine and direct a portion of the working fluid to the secondary flow region to increase a flow capacity of the turbomachine.