Variable cycle gas turbine engine

Claim 2

A variable cycle gas turbine engine comprising: a fan having a forward section axially spaced apart from an aft section; a variable flow bypassing valve disposed intermediate the forward and aft fan sections whereby a portion of the airflow between the forward and aft fan sections may be connected either in serial flow relation or in bypassing parallel relation, and wherein the variable flow bypassing valve includes a plurality of axially extending and circumferentially spaced apart ducts each of which is hinged at one end to the forward fan section to receive a portion of the pressurized airflow exiting from the forward fan section; means for simultaneously rotating the ducts about their hinges; a variable flow geometry inlet duct in direct flow connection to the fan for furnishing an inlet airflow to the fan; a core engine having a compressor, combustor and turbine in serial flow relation wherein the compressor receives another portion of the compressed airflow from the forward and aft fan sections; and a fan turbine drivably connected to the fan.

Claim 3

The variable cycle gas turbine engine of claim 1 wherein: the forward fan section includes a first outer shroud and at least one row of circumferentially spaced apart rotor blades peripherally disposed about a forward fan rotor with each rotor blade having a part span platform extending beyond the full chord thereof in abutting relation with the part span platforms of adjacent blades; the aft fan section includes a second outer shroud; and at least one row of circumferentially spaced apart rotor blades with each rotor blade having a part span platform extending beyond the full chord thereof in abutting relation with the part span platforms for adjacent blades; and there is further included an axially extending part span circumferential platform intermediate the forward and aft fan sections in general coaxial alignment with the forward and aft blade platforms and in spaced apart relation to an inner engine fairing defining an inner core flow annulus in flow connection to the core engine compressor.

Claim 4

The variable cycle gas turbine engine of claim 2 wherein: the forward fan section includes a plurality of circumferentially spaced apart inlet guide vanes extending radially outward from an inner circumferential support ring to the first shroud and a plurality of circumferentially spaced apart outlet guide vanes extending radially outward from the inner engine fairing to the first shroud; the aft fan section includes a plurality of circumferentially spaced apart inlet guide vanes extending radially outward from the inner engine fairing to the second shroud and a plurality of circumferentially spaced apart outlet guide vanes extending radially outward from an inner ring frame to the second shroud; the axially extending part span circumferential platform interconnects the forward fan section outlet guide vanes with the aft fan section inlet guide vanes and there is further included an axially extending circumferential nacelle spaced outward of the first and second shrouds to define first and second plenums respectively wherein the nacelle is also spaced outward from the core engine to define an annular bypass duct therebetween; the variable flow bypassing valve includes a plurality of axially extending and circumferentially spaced apart ducts, each of which is hinged to the first shroud to receive the pressurized airflow exiting from that portion of the forward fan section intermediate the forward part span blade platforms and first shroud; and the means for simultaneously rotating the ducts about their hinges operate so that the outlet airflow exiting from the ducts may be directed either to that portion of the aft fan section intermediate the aft part span blade platforms and second shroud in which caSe the variable geometry inlet simultaneously operates to block inlet airflow to the first plenum, or to the second plenum, in which case the variable geometry inlet simultaneously operates to allow inlet airflow to the first plenum whereupon te airflow is then directed between the spaced apart ducts to that portion of the aft fan section intermediate the aft part span blade platforms and second shroud.

Claim 5

The variable cycle gas turbine engine of claim 3 wherein: the rotating means include a plurality of circumferentially spaced apart actuators, each of which interconnects between one of the spaced apart ducts and the nacelle and a flexible drive shaft extending circumferentially around to interconnect the actuators.

Claim 6

The variable cycle gas turbine engine of claim 3 wherein: the annular bypass duct includes a fan burner stationed therein with the aft end thereof terminating in a variable area nozzle having a convergent primary nozzle and a divergent secondary nozzle; the forward fan secton inlet guide vanes have variable trailing edge flaps; the combustion gases from the core engine discharge through a core engine nozzle defined in part by a variable plug; and there are further included a plurality of bypass passages communicating between the inner core and bypass duct wherein the passages include a valve mechanism for controlling the flow of air therethrough.

Claim 7

A variable cycle gas turbine engine comprising: a fan having a forward section axially spaced apart from an aft section; a variable flow bypassing valve disposed intermediate the forward and aft fan sections whereby a portion of the airflow between the forward and aft fan sections may be connected either in serial flow relation or in bypassing parallel relation, and wherein: the variable flow bypassing valve includes a plurality of axially extending and circumferentially spaced apart ducts, each of which is hinged at one end to the aft fan section; means for simultaneously rotating the ducts about their hinges; a variable flow geometry inlet duct in direct flow connection to the fan for furnishing an inlet airflow to the fan; a core engine having a compressor, combustor and turbine in serial flow relation wherein the compressor receives another portion of the compressed airflow from the forward and aft fan section, and a fan turbine drivably connected to the fan.

Claim 8

A variable cycle gas turbine engine comprising: a fan having a forward section axially spaced apart from an aft section; a variable flow bypassing valve disposed intermediate the forward and aft fan sections whereby a portion of the airflow between the forward and aft fan sections may be connected either in serial flow relation or in bypassing parallel relation, and wherein: the variable flow bypassing valve includes a plurality of axially extending and circumferentially spaced apart ducts, each of which is hinged at one end to the aft fan section; means for simultaneously rotating the ducts about their hinges; a variable flow geometry inlet duct in direct flow connection to the fan for furnishing an inlet airflow to the fan; a core engine having a compressor, combustor and turbine in serial flow relation wherein the compressor receives another portion of the compressed airflow from the forward and aft fan section, and a fan turbine drivably connected to the fan.

Claim 9

The variable cycle gas turbine engine of claim 6 wherein: the forward fan section includes a first outer shroud, and at least one row of circumferentially spaced apart rotor blades peripherally disposed about a forward fan rotor with each rotor blade having a part span platform extending beyond the full chord thereof in abutting relation with the part span platforms of adjacent blades; the aft fan section includes a second outer shroud, and at least one row of circumferentially spaced apart rotor blades with each rotor blade having a part span platform extending beyond the full chord in abutting relation with the part span platforms of adjacent blades; and there is further included an axially extending part span circumferential platform intermediate the forward and aft fan sections in general coaxial alignment with the forward and aft blade platforms and in spaced apart relation to an inner engine fairing defining an inner core flow annulus in flow connection to the core engine compressor.

Claim 10

The variable cycle gas turbine engine of claim 7 wherein: the forward fan section includes a plurality of circumferentially spaced apart inlet guide vanes extending radially outward from an inner circumferential support ring to the first shroud and a plurality of circumferentially spaced apart outlet guide vanes extending radially outward from the inner engine fairing to the first shroud; the aft fan section includes a plurality of circumferentially spaced apart inlet guide vanes extending radially outward from the inner engine fairing to the second shroud and A plurality of circumferentially spaced apart outlet guide vanes extending radially outward from an inner ring frame to the second shroud; the axially extending part span circumferential platform interconnects the forward fan section outlet guide vanes with the aft fan section inlet guide vanes and there is further included an axially extending circumferential nacelle spaced outward of the first and second shrouds to define first and second plenums respectively wherein the nacelle is also spaced outward from the core engine to define an annular bypass duct therebetween; the variable flow bypassing valve includes a plurality of axially extending and circumferentially spaced apart ducts, each of which is hinged to the second shroud to deliver an outlet airflow to that portion of the aft fan section intermediate the aft part span blade platforms and second shroud; and the means for simultaneously rotating the ducts about their hinges operate so that the inlet airflow to the ducts may be received either from that portion of the forward fan section intermediate the forward part span blade platforms and first shroud, in which case the variable geometry inlet simultaneously operates to block inlet airflow to the first plenum, or from the first plenum in whcih case the variable geometry inlet simultaneously operates to allow inlet airflow to the first plenum and whereupon pressurized airflow from that portion of the forward fan section intermediate the forward part span blade platforms and first shroud is directed between the spaced apart ducts to the second plenum.

Claim 11

The variable cycle gas turbine engine of claim 8 wherein: the rotating means include a plurality of circumferentially spaced apart actuators, each of which interconnects between one of the spaced apart ducts and the nacelle, and a flexible drive shaft extending circumferentially around to interconnect the actuators.

Claim 12

The variable cycle gas turbine engine of claim 8 wherein: the annular bypass duct includes a fan burner stationed therein with the aft end thereof terminating in a variable area nozzle having a convergent primary nozzle and a divergent secondary nozzle; the forward fan section inlet guide vanes have variable trailing edge flaps; the combustion gases from the core engine discharge through a core engine nozzle defined in part by a variable plug; and there are further included a plurality of bypass passages communicating between the inner core and bypass duct wherein the passages include a valve mechanism for controlling the flow of air therethrough.

Claim 13

A variable cycle gas turbine engine comprising: a fan having a forward section axially spaced apart from an aft section wherein: the forward fan section includes a first outer shroud, and at least one row of circumferentially spaced apart rotor blades peripherally disposed about a forward fan rotor with each rotor blade having a part span platform extending beyond the full chord thereof in abutting relation with the part span platforms of adjacent blades; and the aft fan section includes a second outer shroud, and at least one row of circumferentially spaced apart rotor blades with each rotor blade having a part span platform extending beyond the full chord thereof in abutting relation with the part span platforms of adjacent blades; a variable flow bypassing valve disposed intermediate the forward and aft fan sections whereby the airflow between the forward and aft fan sections may be connected either in serial flow relation or in bypassing parallel relation; a variable flow geometry inlet duct in direct flow connection to the fan for furnishing an inlet airflow to the fan wherein the variable geometry inlet duct includes: a nacelle extending forwardly of the engine and terminating in a leading edge to provide an inlet opening; a plurality of movable panels interconnected by a plurality of hinges and stationed within the nacelle for movement relative to the nacelle; an inlet wall in fixed spaced apart relation relative to the nacelle defining a first passageway in flow communication with the bypassing valve and a second passageway in flow communication with the forward fan section and further including a first movable panel hinged to the forward edge of the wall whereby the inlet to the first passageway may be closed by movement of the movable panels into engagement with the first movable panel; a core engine having a compressor, combustor and turbine in serial flow relation wherein the compressor receives a portion of the compressed airflow from the fan, and a fan turbine drivably connected to the fan.

Claim 14

A variable cycle gas turbine engine comprising: a fan having a forward section axially spaced apart from an aft section wherein: the forward fan section includes a first outer shroud, and at least one row of circumferentially spaced apart rotor blades peripherally disposed about a forward fan rotor with each rotor blade having a part span platform extending beyond the full chord thereof in abutting relation with the part span platforms of adjacent blades; and the aft fan section includes a second outer shroud, and at least one row of circumferentially spaced apart rotor blades with each rotor blade having a part span platform extending beyond the full chord thereof in abutting relation with the part span platforms of adjacent blades; a variable flow bypassing valve disposed intermediate the forward and aft fan sections whereby the airflow between the forward and aft fan sections may be connected either in serial flow relation or in bypassing parallel relation; a variable flow geometry inlet duct in direct flow connection to the fan for furnishing an inlet airflow to the fan wherein the variable geometry inlet duct includes: a nacelle extending forwardly of the engine and terminating in a leading edge to provide an inlet opening; a plurality of movable panels interconnected by a plurality of hinges and stationed within the nacelle for movement relative to the nacelle; an inlet wall in fixed spaced apart relation relative to the nacelle defining a first passageway in flow communication with the bypassing valve and a second passageway in flow communication with the forward fan section and further including a first movable panel hinged to the forward edge of the wall whereby the inlet to the first passageway may be closed by movement of the movable panels into engagement with the first movable panel; a core engine having a compressor, combustor and turbine in serial flow relation wherein the compressor receives a portion of the compressed airflow from the fan, and a fan turbine drivably connected to the fan.

Claim 15

The variable cycle gas turbine engine of claim 11 wherein: a fixed ramp extends rearward from the nacelle leading edge to define a portion of the inside surface of the variable geometry inlet duct; the plurality of movable panels includes: a second movable panel hinged to the aft edge of the ramp for angular movement relative to the ramp while remaining in sealed relation to the inside of the inlet duct, a first perforated movable panel hinged to the aft edge of the second movable panel, a second perforated movable panel hinged to the aft edge of the first perforated movable panel, a third movable panel hinged to the aft edge of the second perforated panel with the upper edge thereof translatably engaged to the inside surface of the nacelle by a fixed track section, and a flexible seal fixedly connected to the aft edge of the second perforated movable panel for engagement with the first movable panel and a plurality of actuators connecting between the movable panels and nacelle for moving the movable panels.

Claim 16

The variable cycle gas turbine engine of claim 12 including: a two piece collapsible seal having one piece hinged to the inside surface of the nacelle and the other piece hinged to the aft edge of the first perforated movable panel with a center hinge interconnecting the two seal pieces wherein the collapsible seal extends the full transverse width of the inlet duct with the opposing sides thereof in sealing engagement to the inside surface of the nacelle; a first plenum defined by the cooperative arrangement of the nacelle, ramp, second movable panel, first perforated movable panel and collapsible seal for receipt of the boundary layer air bled through the perforations of the first perforated movable panel wherein the first plenum also communicates with a plurality of louvers through the nacelle for discharging the bleed air from the plenum; a second plenum defined by the cooperative arrangement of the nacelle, collapsible seal, second perforated movable panel, and third movable panel for receipt of the boundary layer air bled through the perforations of the second perforated movable panel wherein the second plenum communicates with a second plurality of louvers through the nacelle for discharging the bleed air from the second plenum; an annular duct around the inlet wall in communication with a plurality of perforations extending circumferentially around a portion of the axial length of the inlet wall for receipt of the boundary layer air bled therethrough, and a plurality of circumferentially spaced apart ducts having louvers disposed therein and communicating with the annular duct for the discharge of bleed air collected therein.

Claim 17

The variable cycle gas turbine engine of claim 13 wherein the means for simultaneously rotating the ducts include a plurality of circumferentially spaced apart actuators, each of which interconnects between one of the spaced apart ducts and the engine and a flexible drive shaft extending circumferentially around to interconnect the actuators.

Claim 18

The variable cycle gas turbine engine of claim 13 wherein the ducts maintain a near constant cross-sectional area and assume a near teardrop cross-sectional configuration through a portion of their axial length in order to diffuse the flow passing in the spaces therebetween.

Claim 19

A variable cycle gas turbine engine comprising: a fan having a forward section axially spaced apart from an aft section; variable flow bypassing valve means disposed intermediate the forward and aft fan sections for causing a portion of the airflow between the forward and aft fan sections to be connected either in serial flow realtion or in bypassing parallel relation, and wherein the variable flow bypassing valve means includes a plurality of axially extending and circumferentially spaced apart ducts, each of which is hinged at the same end of the fan; a core engine having a compressor, combustor and turbine in serial flow relation the compressor receives a portion of the compressed airflow from the fan, a fan turbine drivably connected to the fan, and means for simultaneously rotating the ducts about their hinges to a first position wherein a portion of the airflow between the forward and aft fan sections is connected in serial flow relation whereby another portion of the air flowing from both the front and aft fan sections enters the compressor and to a second position wherein a portion of the airflow between the forward and aft fan sections are connected in bypassing parallel relation whereby the air flowing through the front fan section bypasses the aft fan section.

Claim 20

A variable cycle gas turbine engine comprising: a fan having a forward section axially spaced apart from an aft section; variable flow bypassing valve means disposed intermediate the forward and aft fan sections for causing a portion of the airflow between the forward and aft fan sections to be connected either in serial flow realtion or in bypassing parallel relation, and wherein the variable flow bypassing valve means includes a plurality of axially extending and circumferentially spaced apart ducts, each of which is hinged at the same end of the fan; a core engine having a compressor, combustor and turbine in serial flow relation the compressor receives a portion of the compressed airflow from the fan, a fan turbine drivably connected to the fan, and means for simultaneously rotating the ducts about their hinges to a first position wherein a portion of the airflow between the forward and aft fan sections is connected in serial flow relation whereby another portion of the air flowing from both the front and aft fan sections enters the compressor and to a second position wherein a portion of the airflow between the forward and aft fan sections are connected in bypassing parallel relation whereby the air flowing through the front fan section bypasses the aft fan section.

Claim 21

The variable cycle gas turbine engine of claim 16 further including a variable geometry inlet duct in direct flow connection to the fan for furnishing an inlet airflow to the fan.

Claim 22

The variable cycle gas turbine engine of claim 17 wherein the variable flow geometry inlet duct includes means for dividing incoming airflow into inner and outer concentric flow paths.

Claim 23

The variable cycle gas turbine engine of claim 18 wherein said variable geometry inlet duct comprises: a nacelle extending forwardly of the engine and terminating in a leading edge to provide an inlet opening; a plurality of movable panels interconnected by a plurality of hinges ans stationed within the nacelle for movement relative to the nacelle; an inlet wall in fixed spaced apart relation relative to the nacelle defining a first passageway in flow communication with the outer concentric flowpath and a second passageway in flow communication with the inner concentric flowpath and further including a first movable panel hinged to the forward edge of the wall whereby the inlet to the first passageway may be closed by movement of the movable panels into engagement with the first movable panel.

Claim 24

The variable cycle gas turbine engine of claim 19 wherein: a fixed ramp extends rearward from the nacelle leading edge to define a portion of the inside surface of the variable geometry inlet; the plurality of movable panels includes: a second movable panel hinged to the aft edge of the ramp for angular movement relative to the ramp while remaining in sealed relation to the inside of the inlet duct, a first perforated movable panel hinged to the aft edge of the second movable panel, a second perforated panel hinged to the aft edge of the first perforated movable panel, a third movable panel hinged to the edge of the second perforated panel with the upper edge thereof translatably engaged to the inside surface of the nacelle by a fixed track section, and a flexible seal fixedly connected to the aft edge of the second perforated movable panel for engagement with the first movable panel and a plurality of actuators connecting between the movable panels and nacelle for moving the movable panels.

Claim 25

The variable cycle gas turbine engine of claim 19 including: a two piece collapsible seal having one piece hinged to the inside surface of the nacelle and the other piece hinged to the aft edge of the first perforated movable panel with a center hinge interconnecting the two seal pieces wherein the collapsible seal extends the full transverse width of the inlet duct with the opposing sides thereof in sealing engagement to the inside surface of the nacelle; a first plenum defined bY the cooperative arrangement of the nacelle, ramp, second movable panel, first perforated movable panel and collapsible seal for receipt of the boundary layer flow bled through the perforations of the first perforated movable panel wherein the first plenum also communicates with a plurality of louvers through the nacelle for discharging the bleed flow from the plenum; a second plenum defined by the cooperative arrangement of the nacelle, collapsible seal, second perforated movable panel, and third movable panel for receipt of the boudary layer flow bled through the perforations of the second perforated movable panel wherein the second plenum communicates with a second plurality of louvers through the nacelle for discharging the bleed flow from the second plenum; an annular duct around the inlet wall in communication with a plurality of perforations extending circumferentially around a portion of the axial length of the inlet wall for receipt of the boudary layer flow bled therethrough, and a plurality of circumferentially spaced apart ducts having louvers disposed therein and communicating with the annular duct for discharge of bleed flow collected therein.