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Centrifugal turbomachines, such a centrifugal compressors, centrifugal blower, and centrifugal pumps, having unique treatments that enhance their performance ranges. In one arrangement, the treatment involves injecting a relatively high-momentum flow proximate to the blade-tip clearance gap at the i

Centrifugal turbomachines, such a centrifugal compressors, centrifugal blower, and centrifugal pumps, having unique treatments that enhance their performance ranges. In one arrangement, the treatment involves injecting a relatively high-momentum flow proximate to the blade-tip clearance gap at the inlet to the impeller of the turbomachine in a manner that reenergizes flow at the gap. The injected high-momentum flow can be taken from a location downstream of the outlet of the impeller and/or from a flow external to the turbomachine. In another arrangement, the non-self-bleed-type treatment involves providing the centrifugal turbomachine with a secondary flow path upstream of the inlet to the impeller. In one example, the flow of working fluid to the secondary flow path is modulated according to the mass flow of the working fluid. During times of higher flow, the secondary flow path is opened, and at times of lower flow, the secondary flow path is closed.

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1. An apparatus for use in a combustion-gas-charging system of an internal combustion engine (ICE) system, the ICE system including combustion gas systems and exhaust gas systems, the apparatus comprising: a centrifugal compressor that includes: an impeller rotatable about a rotational axis and havi

1. An apparatus for use in a combustion-gas-charging system of an internal combustion engine (ICE) system, the ICE system including combustion gas systems and exhaust gas systems, the apparatus comprising: a centrifugal compressor that includes: an impeller rotatable about a rotational axis and having: an inlet region located proximate to said rotational axis;an outlet region located distal from said rotational axis; anda plurality of blades each having leading and trailing edges and extending between said inlet and outlet regions;a casing defining an intake and having a wall proximate said inlet region of said impeller so as to define a blade-tip clearance gap with said plurality of blades;said intake designed and configured to direct a working fluid to said inlet region of said impeller; anda performance-range-enhancing treatment applied to said intake and designed and configured to enhance the performance range of said centrifugal compressor, wherein said performance-range-enhancing treatment is a non-self-bleed treatment and includes at least one high-momentum-flow injector located upstream of said leading edges and designed and configured to inject a high-momentum flow from a location in said ICE system downstream of said outlet region of said impeller toward said blade-tip clearance gap;wherein said intake comprises a primary flow region for receiving a first portion of the working fluid during operation of said centrifugal compressor, said performance-range-enhancing treatment further comprising: a secondary flow region located radially outward from said primary flow region relative to said rotational axis of said impeller, said secondary flow region for receiving a second portion of the working fluid during operation of said centrifugal compressor; anda 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 working fluid is joined with the first portion of the working fluid downstream of the flow partition. 2. An apparatus according to claim 1, wherein said at least one high-momentum flow injector comprises a Coanda-flow injector having a curved outlet surface that smoothly transitions to said wall of said casing, said Coanda-flow injector being designed and configured to direct the high-momentum flow along said wall toward said blade-tip clearance gap. 3. An apparatus according to claim 2, wherein said Coanda-flow injector has an outlet having a throat having a dimension that is not greater than about said blade-tip clearance gap. 4. An apparatus according to claim 2, wherein said wall has a circumference and said Coanda-flow injector has a continuous opening around said circumference. 5. An apparatus according to claim 1, wherein said wall has a circumference and said at least one high-momentum-flow injector comprises a plurality of Coanda-flow injectors located discretely around said circumference and each having a curved outlet surface that smoothly transitions to said wall of said casing. 6. An apparatus according to claim 1, wherein said at least one high-momentum flow injector comprises an angled-slot injector. 7. An apparatus according to claim 6, wherein said wall has a circumference and said angled-slot injector has a continuous opening around said circumference. 8. An apparatus according to claim 6, wherein said wall has a circumference and said at least one high-momentum-flow injector comprises a plurality of angled-slot injectors located discretely around said circumference. 9. An apparatus according to claim 1, further comprising a self-bleed-type casing treatment. 10. An apparatus according to claim 1, wherein the exhaust gas systems include an exhaust gas recirculation (EGR) system and an exhaust system, wherein said at least one high-momentum flow injector injects at least one of a combustion gas from the combustion gas system, an exhaust gas from the EGR system, or an exhaust gas from the exhaust system. 11. An apparatus according to claim 1, further comprising a diffuser and a volute located downstream of said impeller and at least one flow channel fluidly connecting said at least one high-momentum-flow injector to at least one of said diffuser and said volute. 12. An apparatus according to claim 1, wherein said centrifugal compressor further includes an inducer rotatable about the rotational axis, and said flow partition comprises a shroud on said inducer. 13. An apparatus according to claim 12, wherein said inducer is not split relative to said impeller. 14. An apparatus according to claim 12, wherein said inducer is split relative to said impeller. 15. 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; anda plurality of blades extending between the inlet and outlet regions; anda 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; andprior to said injecting, cooling the high-momentum flow. 16. A method according to claim 15, wherein the working fluid has a first temperature, and said injecting includes injecting the high-momentum flow having a second temperature lower than the first temperature. 17. A method according to claim 15, wherein the working fluid has a first temperature, and said injecting includes injecting the high-momentum flow having a second temperature that is substantially the same as the first temperature. 18. A method according to claim 15, wherein the exhaust gas systems include an exhaust gas recirculation (EGR) system and an exhaust system, wherein said injecting includes injecting a portion of at least one of a combustion gas from the combustion gas system, an exhaust gas from the EGR system, or an exhaust gas from the exhaust system. 19. A method according to claim 18, wherein said cooling step includes cooling the portion of the exhaust-gas recirculation prior to said injecting. 20. A method according to claim 15, wherein said injecting includes injecting a Coanda flow toward the blade-tip-clearance gap. 21. A method according to claim 15, wherein said injecting includes injecting the high-momentum flow immediately upstream of the blade-tip-clearance gap. 22. A method according to claim 15, wherein said injecting further includes injecting high-momentum flow downstream of the blade-tip-clearance gap. 23. A method according to claim 15, wherein the exhaust gas systems include an exhaust gas recirculation (EGR) system for recirculating exhaust gas flow to the ICE, the method further comprising: splitting the exhaust gas flow in the EGR system between a first portion and a second portion; androuting the first portion of the exhaust gas flow directly from the EGR system to the ICE;wherein said injecting includes injecting the second portion of the exhaust gas with the high-momentum-flow injector. 24. A method according to claim 23, further comprising cooling the second portion of the exhaust gas flow prior to said injecting. 25. 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; andat 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. 26. A system according to claim 25, wherein said internal combustion engine is a reciprocating engine. 27. A system according to claim 25, further comprising an exhaust system for carrying the exhaust gas away from said exhaust gas outlet, said exhaust system including an expansion turbine mechanically coupled to said centrifugal compressor and designed and configured to drive said centrifugal compressor. 28. A system according to claim 25, wherein said centrifugal compressor is mechanically driven by said internal combustion engine. 29. A system according to claim 25, further comprising an exhaust-gas cooler fluidly coupled between said flow injector and said exhaust-gas outlet, wherein said exhaust-gas cooler is designed and configured to cool the flow provided by said flow injector to said centrifugal compressor. 30. A system according to claim 25, wherein said centrifugal compressor includes: 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; anda plurality of blades extending between the inlet and outlet regions; anda shroud circumferentially surrounding the impeller so as to defined a blade-tip-clearance gap between the shroud and the plurality of blades;wherein said at least one flow injector is designed and configured to direct the flow so as to reenergize flow at said blade-tip-clearance gap. 31. A system according to claim 30, wherein said at least one flow injector comprises a Coanda flow injector located upstream of said blade-tip-clearance gap. 32. A system according to claim 31, wherein said at least one flow injector comprises an angled slot injector. 33. A system according to claim 32, wherein said angled slot injector is located upstream from said inlet region of said impeller. 34. A system according to claim 32, wherein said angled slot injector is located downstream from said inlet region of said impeller. 35. 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; anda plurality of impeller blades extending between said impeller inlet and outlet and extending from said impeller hub to a location adjacent said casing wall; andan 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; anda 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. 36. An apparatus according to claim 35, wherein said secondary flow region has a substantially annular shape that is concentric around said primary flow region. 37. An apparatus according to claim 35, wherein said casing wall has a first inside diameter at a location downstream of said throat region and a second inside diameter at a location upstream from said throat region, wherein said first inside diameter is smaller than said second inside diameter. 38. An apparatus according to claim 37, wherein said secondary flow region has a radial height relative to said rotational axis, and said second inside diameter is substantially equal to said first inside diameter plus twice said radial height. 39. An apparatus according to claim 37, wherein said partial shroud is located so that said primary flow region within said inducer has a third inside diameter substantially equal to said first inside diameter. 40. An apparatus according to claim 35, wherein said performance-range-enhancing treatment includes a divider wall separating said primary flow region from said secondary flow region. 41. An apparatus according to claim 35, wherein said flow modulator is designed and configured to modulate flow of the working fluid to the portion of said inducer radially outward from said partial shroud relative to said rotational axis. 42. An apparatus according to claim 41, wherein said flow modulator is spaced from said inducer upstream from said inducer and said performance-range-enhancing treatment further includes a divider wall located between said flow modulator and said inducer. 43. An apparatus according to claim 42, wherein said divider wall is substantially radially aligned with said partial shroud. 44. An apparatus according to claim 35, wherein said inducer is spaced from said impeller by said throat region. 45. An apparatus according to claim 35, wherein each of said plurality of blades on said impeller has a leading edge at said impeller inlet and said partial shroud has a downstream end located substantially at said leading edge. 46. An apparatus according to claim 35, wherein said flow modulator comprises variable guide vanes. 47. An apparatus according to claim 35, wherein said flow modulator comprises shutters. 48. An apparatus according to claim 35, further comprising a controller designed and configured to control said flow modulator so as to increase flow of the working fluid in said secondary flow region during times of relatively high flow of the working fluid and to decrease flow of the working fluid in said secondary flow region during times of relatively low flow of the working fluid. 49. An apparatus according to claim 35, further comprising a self-bleed-type casing treatment for recirculating a portion of the working fluid from said centrifugal turbomachine to said intake. 50. An apparatus according to claim 49, wherein said self-bleed-type casing treatment includes a suction end located at said impeller proximate said inlet, and an injection end located upstream of said flow modulator. 51. 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; andan 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; andduring 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. 52. A method according to claim 51, wherein said opening the flow modulator includes opening a valve. 53. A method according to claim 51, wherein said opening the flow modulator includes adjusting a set of guide vanes. 54. A method according to claim 51, further comprising increasing the density of the portion of working fluid in the secondary flow region prior to the portion reaching the impeller. 55. A method according to claim 54, wherein said increasing the density of the portion of working fluid includes increasing the density using the inducer. 56. A method according to claim 51, further comprising monitoring the flow of the working fluid entering the centrifugal turbomachine and modulating the portion of the working fluid directed to the secondary flow region as a function of said monitoring.