Combustion apparatus with combustion and dilution air modulating means

Claim 2

A COMBUSTION APPARATUS ADAPTED FOR USE IN A GAS TURBINE ENGINE CHARACTERIZED BY SUBSTANTIALLY COMPLETE COMBUSTION OF IQUID HYDROCARBON FUEL AND BY A LOW OUTPUT OF NITROGEN OXDES, THE APPARATUS COMPRISING A COMBUSTION LINER HAVING A DISCHARGE OUTLET FOR COMBUSTION PRODUCTS AT THE DOWNSTREAM AND OF THE LINER; THE LINER HAVING AN UPSTREAM END AND LINER WALL MEANS EXTENDING FROM THE UPSTREAM END TO THE DOWNSTREAM END, THE WALL MEANS ENCLOSING, IN SEQUENCE FROM THE UPSTREAM END TO THE DOWNSTREAM END, A PRECHAMBER,A REACTION ZONE, AND A DILUTION ZONE; THE PRECHAMBER INCLUDING FIRST AIR ENTRANCE MEANS AT ITS UPSTREAM END EFFECTIVE TO DIRECT COMBUSTION AIR WITH A SUBSTANTIAL TRANSVERSE VELOCITY COMPONENT DOWNSTREAM OVER THE INNER SURFACE OF THE PRECHAMBER WALL MEANS, LIQUID FUEL INTRODUCTION MEANS DOWNSTREAM OF THE SWIRLER MEANS DISPOSED TO LAY A FILM OF LIQUID FUEL ON THE SAID INNER SURFACE FOR EVAPORATION BY MIXTURE WITH THE SAID COMBUSTION AIR, AND SECOND AIR ENTRANCE MEANS THROUGH THE PRECHAMBER ADAPTED TO INTRODUCE AIR TO DILUTE THE FUEL-AIR MIXTURE, WHEREIN THE IMPROVEMENT COMPRISES A STRUCTURE OF THE SECOND AIR ENTRANCE MEANS PROVIDING A RING OF AIR ENTRANCE PORTS EXTENDING RADIALLY THROUGH THE PRECHAMBER WALL MEANS DISTRIBUTED AROUND THE PRECHAMBER, THE PORTS HAVING A CONFIGURATION INCLUDING LATERAL WALLS SUBSTANTIALLY INCLINED TO THE RADIAL DIRECTION SUCH AS TO INTRODUCE THE AIR RADIALLY INTO THE PRECHAMBER WITH A SUBSTANTIAL CIRCUMFERENTIAL COMPONENT OF MOTION IN THE SAME DIRECTION AS THE TRANSVERSE VELOCITY COMPONENT OF THE AIR FLOWING FROM THE FIRST ENTRANCE MEANS AND NO SIGNIFICANT AXIAL COMPONENT OF VELOCITY, RELATIVE TO THE AXIAL COMPONENT OF VELOCITY OF THE FUEL-AIR MIXTURE, THE PORTS BEING TAPERED AXIALLY OF THE PRECHAMBER, AND COMPRISES MEANS FOR VARYING THE FLOW CAPACITY OF THE SECOND AIR ENTRANCE MEANS INCLUDNG A SLEEVE SURROUNDING AND RECIPROCABLE AXIALLY OF THE PRECHAMBER WALL, THE SLEEVE HAVING V-NOTCHED EDGE PORTIONS COOPERATION WITH AT LEAST SOME OF THE PORTS SO AS TO PROVIDE GRADUATED MODULATION OF THE FLOW AREA DURING INITIAL OPENING AND FINAL CLOSING MOVEMENT OF THE SLEEVE.

Claim 3

A combustion apparatus adapted for use in a gas turbine engine characterized by substantially complete combustion of liquid hydrocarbon fuel and by a low output of nitrogen oxides, the apparatus comprising a combustion liner having a discharge outlet for combustion products at the downstream end of the liner; the liner having an upstream end and liner wall means extending from the upstream end to the downstream end, the wall means enclosing, in sequence from the upstream end to the downstream end, a prechamber, a reaction zone, and a dilution zone; the prechamber being of significantly smaller cross-sectional area than the reaction zone and beng joined to the reaction zone by an abruptly diverging wall portion; the prechamber including first air entrance means defined by swirler means at its upstream end effective to direct combustion air with a substantial transverse velocity component downstream over the inner surface of the prechamber wall means, liquid fueL introduction means downstream of the swirler means disposed to lay a film of liquid fuel on the said inner surface for evaporation by and mixture with the said combustion air, second air entrance means through the prechamber wall means near the downstream end of the prechamber adapted to introduce air to dilute the fuel-air mixture, and means for varying the flow capacity of the second air entrance means; the reaction zone providing turbulent recirculating flow of burning fuel-air mixture and combustion products resulting from the swirl of the entering mixture and the abrupt divergence of the wall means; the dilution zone including dilution air entrance means to admit air for mixture with recirculating gas in the reaction zone and dilution of the combustion products flowing from the reaction zone to the discharge outlet; means for varying the flow capacity of the dilution air entrance means; and actuating means connected to both said flow capacity varying means effective to vary the flow capacity of both said air entrance means concurrently and in reverse sense; the range of variation of the entrance means being sufficient to maintain an equivalence ratio of about 0.25 to 0.5 in the fuel-air mixture flowing from the prechamber into the reaction zone throughout the normal range of operation of the combustion apparatus, wherein the improvement comprises a structure of the second air entrance means providing a ring of air entrance ports extending radially through the prechamber wall means distributed around the prechamber, the ports having a configuration including lateral walls substantially inclined to the radial direction such as to introduce the air radially into the prechamber with a substantial circumferential component of motion in the same direction as the transverse velocity component of the air flowing from the first entrance means and no significant axial component of velocity relative to the axial component of velocity of the fuel-air mixture, the ports being tapered axially of the prechamber, and comprises means for varying the flow capacity of the second air entrance means including a sleeve surrounding and reciprocable axially of the prechamber wall, the sleeve having V-notched edge portions cooperating with at least some of the ports so as to provide graduated modulation of the flow area during initial opening and final closing movement of the sleeve.

Claim 4

A combustion apparatus adapted for use in a gas turbine engine characterized by substantially complete combustion of liquid hydrocarbon fuel and by a low output of nitrogen oxides, the apparatus comprising a combustion liner having a discharge outlet for combustion products at the downstream end of the liner; the liner having an upstream end and liner wall means extending from the upstream end to the downstream end, the wall means enclosing, in sequence from the upstream end to the downstream end, a prechamber, a reaction zone, and a dilution zone; the prechamber being of significantly smaller cross-sectional area than the reaction zone and beng joined to the reaction zone by an abruptly diverging wall portion; the prechamber including first air entrance means defined by swirler means at its upstream end effective to direct combustion air with a substantial transverse velocity component downstream over the inner surface of the prechamber wall means, liquid fueL introduction means downstream of the swirler means disposed to lay a film of liquid fuel on the said inner surface for evaporation by and mixture with the said combustion air, second air entrance means through the prechamber wall means near the downstream end of the prechamber adapted to introduce air to dilute the fuel-air mixture, and means for varying the flow capacity of the second air entrance means; the reaction zone providing turbulent recirculating flow of burning fuel-air mixture and combustion products resulting from the swirl of the entering mixture and the abrupt divergence of the wall means; the dilution zone including dilution air entrance means to admit air for mixture with recirculating gas in the reaction zone and dilution of the combustion products flowing from the reaction zone to the discharge outlet; means for varying the flow capacity of the dilution air entrance means; and actuating means connected to both said flow capacity varying means effective to vary the flow capacity of both said air entrance means concurrently and in reverse sense; the range of variation of the entrance means being sufficient to maintain an equivalence ratio of about 0.25 to 0.5 in the fuel-air mixture flowing from the prechamber into the reaction zone throughout the normal range of operation of the combustion apparatus, wherein the improvement comprises a structure of the second air entrance means providing a ring of air entrance ports extending radially through the prechamber wall means distributed around the prechamber, the ports having a configuration including lateral walls substantially inclined to the radial direction such as to introduce the air radially into the prechamber with a substantial circumferential component of motion in the same direction as the transverse velocity component of the air flowing from the first entrance means and no significant axial component of velocity relative to the axial component of velocity of the fuel-air mixture, the ports being tapered axially of the prechamber, and comprises means for varying the flow capacity of the second air entrance means including a sleeve surrounding and reciprocable axially of the prechamber wall, the sleeve having V-notched edge portions cooperating with at least some of the ports so as to provide graduated modulation of the flow area during initial opening and final closing movement of the sleeve.

Claim 5

A combustion apparatus adapted for use in a gas turbine engine characterized by substantially complete combustion of liquid hydrocarbon fuel and by a low output of nitrogen oxides, the apparatus comprising a combustion liner having a discharge outlet for combustion products at the downstream end of the liner; the liner having an upstream end and liner wall means extending from the upstream end to the downstream end, the wall means enclosing, in sequence from the upstream end to the downstream end, a prechamber, a reaction zone, and a dilution zone; the prechamber including first air entrance means at its upstream end effective to direct combustion air with a substantial transverse velocity component downstream over the inner surface of the prechamber wall means, liquid fuel introduction means downstream of the swirler means disposed to lay a film of liquid fuel on the said inner surface for evaporation by and mixture with the said combustion air, and second air entrance means through the prechamber wall means near the downstream end of the prechamber adapted to introduce air to dilute the fuel-air mixture, wherein the improvement comprises a structure of the second air entrance means providing a ring of air entrance ports extending radially through the prechamber wall means distributed around the prechamber, the ports having a configuration including lateral walls substantially inclined to the radial direction such as to introduce the air radially into the prechamber with a substantial circumferential component of motion in the same direction as the transverse velocity component of the air floWing from the first entrance means and no significant axial component of velocity relative to the axial component of the velocity of the fuel-air mixture, and comprises means for varying the flow capacity of the second air entrance means including a sleeve surrounding and reciprocable axially of the prechamber wall, the sleeve having V-notched edge portions cooperating with at least some of the ports so as to provide graduated modulation of the flow area during initial opening and final closing movement of the sleeve.

Claim 6

A combustion apparatus adapted for use in a gas turbine engine characterized by substantially complete combustion of liquid hydrocarbon fuel and by a low output of nitrogen oxides, the apparatus comprising a combustion liner having a discharge outlet for combustion products at the downstream end of the liner; the liner having an upstream end and liner wall means extending from the upstream end to the downstream end, the wall means enclosing, in sequence from the upstream end to the downstream end, a prechamber, a reaction zone, and a dilution zone; the prechamber including first air entrance means at its upstream end effective to direct combustion air with a substantial transverse velocity component downstream over the inner surface of the prechamber wall means, liquid fuel introduction means downstream of the swirler means disposed to lay a film of liquid fuel on the said inner surface for evaporation by and mixture with the said combustion air, and second air entrance means through the prechamber wall means near the downstream end of the prechamber adapted to introduce air to dilute the fuel-air mixture, wherein the improvement comprises a structure of the second air entrance means providing a ring of air entrance ports extending radially through the prechamber wall means distributed around the prechamber, the ports having a configuration including lateral walls substantially inclined to the radial direction such as to introduce the air radially into the prechamber with a substantial circumferential component of motion in the same direction as the transverse velocity component of the air floWing from the first entrance means and no significant axial component of velocity relative to the axial component of the velocity of the fuel-air mixture, and comprises means for varying the flow capacity of the second air entrance means including a sleeve surrounding and reciprocable axially of the prechamber wall, the sleeve having V-notched edge portions cooperating with at least some of the ports so as to provide graduated modulation of the flow area during initial opening and final closing movement of the sleeve.

Claim 7

A combustion apparatus adapted for use in a gas turbine engine characterized by substantially complete combustion of liquid hydrocarbon fuel and by a low output of nitrogen oxides, the apparatus comprising a combustion liner having a discharge outlet for combustion products at the downstream end of the liner; the liner having an upstream end and liner wall means extending from the upstream end to the downstream end, the wall means enclosing, in sequence from the upstream end to the downstream end, a prechamber, a reaction zone, and a dilution zone; the prechamber being of significantly smaller cross-sectional area than the reaction zone and being joined to the reaction zone by an abruptly diverging wall portion; the prechamber including first air entrance means defined by swirler means at its upstream end effective to direct combustion air with a substantial transverse velocity component downstream over the inner surface of the prechamber wall means, liquid fuel introduction means downstream of the swirler means disposed to lay a film of liquid fuel on the said inner surface for evaporation by and mixture with the said combustion air, second air entrance means through the prechamber wall means near the downstream end of the prechamber adapted to introduce air to dilute the fuel-air mixture, and means for varying the flow capacity of the second air entrance means; the reaction zone providing turbulent recirculating flow of burning fuel-air mixture and combustion products resulting from the swirl of the entering mixture and the abrupt divergence of the wall means; the dilution zone including dilution air entrance means to admit air for mixture will recirculating gas in the reaction zone and dilution of the combustion products flowing from the reaction zone to the discharge outlet; means for varying the flow capacity of the dilution air entrance means, and actuating means connected to both said flow capacity varying means effective to vary the flow capacity of both said air entrance means concurrently and in reverse sense; the range of variation of the entrance means being sufficient to maintain an equivalence ratio of about 0.25 to 0.5 in the fuel-air mixture flowing from the prechamber into the reaction zone throughout the normal range of operation of the combustion apparatus, wherein the improvement comprises a structure of the second air entrance means providing a ring of air entrance ports extending radially through the prechamber wall means distributed around the prechamber, the ports having a configuration including lateral walls substantially inclined to the radial direction such as to introduce the air radially into the prechamber with a substantial circumferential component of motion in the same direction as the transverse velocity component of the air flowing from the first entrance means and no significant axial component of velocity relative to the axial component of velocity of the fuel-air mixture, and comprises means for varying the flow capacity of the second air entrance means including a sleeve surrounding and reciprocable axially of the prechamber wall, the sleeve having V-notched edge portions cooperating with at least some of the ports so as to provide graduated modulation of the flow area during initial opening and final closing movement of the sleeve.

Claim 8

A combustion apparatus adapted for use in a gas turbine engine characterized by substantially complete combustion of liquid hydrocarbon fuel and by a low output of nitrogen oxides, the apparatus comprising a combustion liner having a discharge outlet for combustion products at the downstream end of the liner; the liner having an upstream end and liner wall means extending from the upstream end to the downstream end, the wall means enclosing, in sequence from the upstream end to the downstream end, a prechamber, a reaction zone, and a dilution zone; the prechamber being of significantly smaller cross-sectional area than the reaction zone and being joined to the reaction zone by an abruptly diverging wall portion; the prechamber including first air entrance means defined by swirler means at its upstream end effective to direct combustion air with a substantial transverse velocity component downstream over the inner surface of the prechamber wall means, liquid fuel introduction means downstream of the swirler means disposed to lay a film of liquid fuel on the said inner surface for evaporation by and mixture with the said combustion air, second air entrance means through the prechamber wall means near the downstream end of the prechamber adapted to introduce air to dilute the fuel-air mixture, and means for varying the flow capacity of the second air entrance means; the reaction zone providing turbulent recirculating flow of burning fuel-air mixture and combustion products resulting from the swirl of the entering mixture and the abrupt divergence of the wall means; the dilution zone including dilution air entrance means to admit air for mixture will recirculating gas in the reaction zone and dilution of the combustion products flowing from the reaction zone to the discharge outlet; means for varying the flow capacity of the dilution air entrance means, and actuating means connected to both said flow capacity varying means effective to vary the flow capacity of both said air entrance means concurrently and in reverse sense; the range of variation of the entrance means being sufficient to maintain an equivalence ratio of about 0.25 to 0.5 in the fuel-air mixture flowing from the prechamber into the reaction zone throughout the normal range of operation of the combustion apparatus, wherein the improvement comprises a structure of the second air entrance means providing a ring of air entrance ports extending radially through the prechamber wall means distributed around the prechamber, the ports having a configuration including lateral walls substantially inclined to the radial direction such as to introduce the air radially into the prechamber with a substantial circumferential component of motion in the same direction as the transverse velocity component of the air flowing from the first entrance means and no significant axial component of velocity relative to the axial component of velocity of the fuel-air mixture, and comprises means for varying the flow capacity of the second air entrance means including a sleeve surrounding and reciprocable axially of the prechamber wall, the sleeve having V-notched edge portions cooperating with at least some of the ports so as to provide graduated modulation of the flow area during initial opening and final closing movement of the sleeve.