Hot air injection for swirling rotational anti-icing system

• US 6,267,328 B1
• Filed: 10/21/1999
• Issued: 07/31/2001
• Est. Priority Date: 10/21/1999
• Status: Expired due to Term

• Current Assignee: ROHR Incorporated (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: ROHR Incorporated (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Vest, Michael S.
• Primary Examiner(s): Swiatek, Robert P.
• Application Number:
  US09/422,918
• Time in Patent Office: 649 Days
• Field of Search: 244/134.B, 244/53.B, 244/134.R, 244/207, 244/210, 244/129.4, 244/129.5, 60/390.7, 602/62, 239/265.11, 239/296, 239/599, 239/428.5
• US Class Current: 244/134.00B
• CPC Class Codes: B64D 15/04 Hot gas application
• CPC Class Codes: B64D 2033/0233 comprising de-icing means

Abstract

An anti-icing system for a nose cowl of an aircraft jet engine. An improved injection nozzle is provided to enhance the injection of hot, pressure gas from the engine into the ambient air within the nose cowl to entrain such air and cause the entrained mass to rotate within the nose cowl in swirling rotational motion and thereby cause the temperature of the nose cowl to rise sufficiently to preclude the formation of ice thereon during flight. The improved injection nozzle preferably includes a plurality of serially spaced elliptically shaped jet nozzles arranged longitudinally and tangentially to the center line of the nose cowl to create vorticity in the resultant injected hot gas flow and enhance its mixture with the ambient air within the nose cowl and thereby preclude any tendency for the formation of an area of elevated temperature in the skin of the nose cowl aft of the position of the injection nozzle under certain design criteria.

Claims

1. An anti-icing system comprising:

a substantially closed annular single skin nose cowl having an exterior surface and an interior surface and positioned at the leading edge of an inlet of an aircraft jet engine propulsion system and arranged for grazing flow of ambient air over the exterior surface when the aircraft is in flight, the annular nose cowl containing a quantity of air;

a source of high pressure hot gas;

at least one conduit coupled to the source of high pressure hot gas and having an outlet end coupled to said nose cowl;

an outlet nozzle provided on the outlet end of said at least one conduit, said outlet nozzle including a plurality of spaced elliptically shaped jet nozzles to create turbulence and transverse sting in the hot gas low, said jet nozzles being oriented to eject said hot gas at high velocity in a direction substantially tangential to a centerline of said annular nose cowl, and

whereby the turbulent high velocity hot gas flow issuing from the jet nozzles entrain air within said annular nose cowl so that the total volume of air and hot gases swirling around the interior of said annular nose cowl in a rotational direction has a substantially uniform temperature intermediate between that of said air and said hot gas flow and by direct contact with the interior surface of the nose cowl substantially uniformly heats the single skin nose cowl to a temperature that is sufficiently high to preclude the formation of ice on the exterior surface of the single skin nose cowl by the grazing flow of ambient air when the aircraft is in flight while also precluding the creation of an area of unduly elevated temperature in said nose cowl at a location aft of said outlet nozzle.

2. The anti-icing system of claim 1 wherein the annular nose cowl is closed by a transverse bulkhead and an air outlet means is provided in the annular nose cowl to permit a volume of swirling heated air and hot gas to be exhausted at rate substantially equal to the volume of hot gas being injected into the housing through said at least one conduit.

3. The anti-icing system of claim 2 wherein the jet nozzles of the outlet nozzle are positioned about 90°

with respect to said bulkhead to provide said tangential orientation.

4. The anti-icing system of claim 3 wherein said plurality of jet nozzles are spaced from and extend serially longitudinally from the bulkhead into the annular nose cowl.

5. The anti-icing system of claim 3 wherein the number of spaced jet nozzles falls within a range of 2-4 and such jet nozzles are arranged longitudinally from the bulkhead.

6. The anti-icing system of claim 5 wherein each of said elliptically shaped jet nozzles has an outlet area having a horizontal length that is at least three times the height of such area.

7. The anti-icing system of claim 6 wherein each of said elliptically shaped jet nozzles has an outlet area having a vertical height that is at least three times the horizontal length of such area.

8. The anti-icing system of claim 7 wherein the cross-sectional area of the at least one conduit is greater that the total outlet nozzle area of the plurality of the jet nozzles to insure that all such jet nozzles receive a supply of hot gas having substantially the same pressure.

9. The anti-icing system of claim 8 wherein the plurality of jet nozzles are serially arranged and extend longitudinally into the nose cowl a distance that is no more than two/thirds of the distance from the leading edge of the nose cowl to the bulkhead.

10. The anti-icing system of claim 8 wherein the plurality of jet nozzles are serially arranged and extend longitudinally from the bulkhead a distance that is greater than two/thirds the distance from the leading edge of the nose cowl to the bulkhead but which permits the jet nozzle spaced furthest from the bulkhead to be spaced sufficiently distant from a leading edge of the nose cowl to preclude an area of unduly elevated temperature in an area of the nose cowl aft of the flow of hot gas from such jet nozzle.

11. The anti-icing system of claim 1 wherein the outlet nozzle injects a hot stream of gas into the mass of air within the nose cowl at a rate to provide a mass flow rate, of the hot gas and air swirling in said annular nose cowl in a rotational direction around the interior of said annular nose cowl and in direct contact with the interior surface of such nose cowl, being at least about three times the mass flow rate of mixed air and hot gases leaving said outlet.

12. An anti-icing system for annular aircraft jet engine inlet cowls which comprises:

a substantially annular single skin nose lip having an exterior surface and an interior surface and positioned at the leading portion of an aircraft jet engine;

a bulkhead substantially closing the aft end of said single skin nose lip to provide an annular D-shaped duct;

a region of the jet engine having therein a hot, high pressure gas;

at least one conduit adapted to carry hot gas from said region having a temperature of about 100 to 500 degrees F. and a velocity of about 3 to 30 ft./min, said at least one conduit having an outlet end coupled to said housing through said bulkhead;

an outlet nozzle which includes a plurality of spaced hot gas injection nozzles coupled to said outlet end of said conduit each injection nozzle having an elliptical shape and being oriented to eject said hot gas at a high velocity in a direction substantial tangential to the centerline of said annular nose lip and into the flow of hot gas issuing from said nozzle to create turbulence in said hot gas flow, and

the turbulent high velocity hot gas flow issuing from each injection nozzle entrains air within said annular single skin nose lip so that the total volume of air and hot gas swirling around the interior of said annular nose lip in a rotational direction has a substantially uniform temperature of from 35 to 41 degrees F. when the outside air temperature is about −

40 degrees F. and the mass flow rate of said hot gas and air is about three times the mass flow rate of the gases leaving said outlet nozzle whereby such rotating hot gas and air by direct contact with the interior surface of said single skin annular nose lip raises the temperature of said D-shaped duct to a substantially uniform temperature that is sufficiently high to preclude the formation of ice on the exterior surface of said nose lip while simultaneously precluding the creation of an area of elevated temperature in said nose lip at a location aft of the point of injection of hot gas through said outlet injection nozzles.

13. The anti-icing system of claim 12 that also includes an exhaust means that is sized to permit the exhaust of a volume of swirling air and hot gas from within the D-shaped duct at least equal to the volume of hot gas injected into the D-shaped duct though the plurality of jet nozzles.

14. The anti-icing system of claim 13 wherein there are three jet nozzles.

15. The anti-icing system of claim 14 wherein the three jet nozzles extend longitudinally from the bulkhead into the D-shaped duct a distance that is no greater than two/thirds the distance from a leading edge of the nose lip to said bulkhead.

16. The anti-icing system of claim 13 wherein there are four jet nozzles.

17. The anti-icing system of claim 16 wherein the four nozzles are serially arranged and extend longitudinally from the bulkhead into the D-shaped duct a distance that is greater than two/thirds of the distance from the bulkhead to the leading edge of the nose lip.

18. A method of providing an anti-icing system for a nose cowl for an annular air inlet of an aircraft jet engine propulsion system which precludes the creation of a hot spot on such nose cowl in the vicinity of injection of high pressure hot gas into such nose cowl, which method comprises the steps of:

providing a single skin nose cowl positioned at the leading edge of an air inlet of an aircraft jet engine that is substantially closed by an aft bulkhead to enclose a quantity of air;

providing a source of high pressure hot gas;

introducing said high pressure hot gas into the quantity of air enclosed within said nose cowl in a direction substantially tangential to a centerline of said nose cowl to entrain the mass of gas within the nose cowl to create a volume of hot gas and air swirling in a rotational direction around the interior of said nose cowl at a substantially uniform temperature that is sufficiently high to preclude the formation of ice on an exterior surface of said nose cowl during flight, and

creating turbulence and transverse stirring within the flow of high pressure hot gas during its introduction into said quantity of air by introducing such hot gas through a plurality of spaced elliptically shaped injection nozzles to thereby enhance the commingling of said hot gas and said quantity of air to preclude the creation of an area of elevated temperature on said nose cowl at a position aft of the point of introduction of said hot gas.

19. The method of claim 18 wherein the step of creating turbulence and transverse stirring within the flow of high pressure hot gas includes arranging such spaced injection nozzles to extend longitudinally into said nose cowl from the aft bulkhead.

20. The method of claim 19 which further includes the step of forming the shape of each elliptically shaped injection nozzle to have one dimension that is at least three times greater than its transverse dimension.

21. The method of claim 18 wherein the step of creating turbulence and transverse stirring within the flow of high pressure hot gas is created by introducing such hot gas through a single elliptically shaped injection nozzle arranged within said nose cowl in a direction tangential to the center line of said nose cowl to thereby enhance the commingling of said hot gas and said quantity of air to precluded the creation of an area of elevated temperature on said nose cowl at a position aft of the point of introduction of said hot gas.

22. An anti-icing apparatus comprising:

a substantially closed annular nose cowl comprising an exterior surface and an interior surface and capable of being positioned at the leading edge of an inlet of an aircraft jet engine propulsion system;

at least one conduit comprising an outlet end coupled to the nose cowl, wherein the at least one conduit is capable of being coupled to a source of high pressure hot gas; and

an outlet nozzle provided on the outlet end of the conduit, wherein the outlet nozzle comprises a plurality of spaced elliptically shaped jet nozzles oriented to eject hot gas in a direction substantially tangential to a centerline of the nose cowl.

23. The apparatus of claim 22, wherein the nose cowl is closed by a transverse bulkhead and the nose cowl further comprises an outlet to permit air and gas to exit the nose cowl.

24. The apparatus of claim 23, wherein the jet nozzles are positioned about 90°

with respect to the bulkhead.

25. The apparatus of claim 23, wherein the jet nozzles are spaced from and extend longitudinally from the bulkhead into the annular nose cowl.

26. The apparatus of claim 22, wherein each of the jet nozzles has an outlet area having a horizontal length that is at least three times the vertical height of the area.

27. The apparatus of claim 22, wherein each of the jet nozzles has an outlet area having a vertical height that is at least three times the horizontal length of the area.

28. The apparatus of claim 22, wherein the cross-sectional area of the conduit is greater than the total outlet area of all the jet nozzles.

29. The apparatus of claim 22, wherein the nose cowl is close by a transverse bulkhead and provides an annular D-shaped duct.

30. The apparatus of claim 29, wherein the nose cowl additionally comprises an outlet to permit air and gas to exit the D-shaped duct.

31. An anti-icing system comprising:

a substantially closed annular single skin nose cowl having an exterior surface and an interior surface and positioned at the leading edge of an inlet of an aircraft jet engine propulsion system and arranged for grazing flow of ambient air over the exterior surface when the aircraft is in flight, the annular nose cowl containing a quantity of air;

a source of high pressure hot gas;

at least one conduit coupled to the source of high pressure hot gas and having an outlet end coupled to said nose cowl;

an outlet nozzle provided on the outlet end of said at least one conduit, said outlet nozzle having a configuration selected from the group consisting of (i) a single elliptically shaped jet nozzle having an outlet area having a horizontal length which is eight times the vertical height of the nozzle, (ii) three elliptically shaped jet nozzles each having an outlet area having a vertical height which is three times the horizontal length for each nozzle, (iii) four elliptically shaped jet nozzles each having an outlet area having a vertical height which is three times the horizontal length for each nozzle, and (iv) four elliptically shaped jet nozzles each having an outlet area having a horizontal length which is three times the vertical height for each nozzle, wherein said jet nozzle or nozzles are oriented to eject said hot gas at high velocity in a direction substantially tangential to a centerline of said annular nose cowl, and

whereby the turbulent high velocity hot gas flow issuing front the jet nozzle or nozzles entrain air within said annular nose cowl so that the total volume of air and hot gases swirling around the interior of said annular nose cowl in a rotational direction has a substantially uniform temperature intermediate between that of said air and said hot gas flow and by direct contact with the interior surface of the nose cowl substantially uniformly heats the single skin nose cowl to a temperature that is sufficiently high to preclude the formation of ice on the exterior surface of the single skin nose cowl by the grazing flow of ambient air when the aircraft is in flight while also precluding the creation of an area of unduly elevated temperature in said nose cowl at a location aft of said outlet nozzle.

32. An anti-icing system comprising:

a substantially annular single skin nose lip having an exterior surface and an interior surface and positioned at the leading portion of an aircraft jet engine;

a bulkhead substantially closing the aft end of said single skin nose lip to provide an annular D-shaped duct;

a region of the jet engine having therein a hot, high pressure gas;

at least one conduit adapted to carry hot gas from said region having a temperature of about 100 to 500 degrees F. and a velocity of about 3 to 30 ft./min, said at least one conduit having an outlet end coupled to said housing through said bulkhead;

an outlet nozzle having a configuration selected from the group consisting of (i) a single elliptically shaped jet nozzle having an outlet area having a horizontal length which is eight times the vertical height of the nozzle, (ii) three elliptically shaped jet nozzles each having an outlet area having a vertical height which is three times the horizontal length for each nozzle, (iii) four elliptically shaped jet nozzles each having an outlet area having a vertical height which is three times the horizontal length for each nozzle, and (iv) four elliptically shaped jet nozzles each having an outlet area having a horizontal length which is three times the vertical height for each nozzle, wherein said jet nozzle or nozzles are oriented to eject said hot gas at high velocity in a direction substantially tangential to the centerline of said annular nose lip and into the flow of hot gas issuing from said outlet nozzle to create turbulence in said hot gas flow, and

the turbulent high velocity hot gas flow issuing from the outlet nozzle entrains air within said annular single skin nose lip so that the total volume of air and hot gas swirling around the interior of said annular nose lip in a rotational direction has a substantially uniform temperature of from 35 to 41 degrees F. when the outside air temperature is about −

40 degrees F. and the mass flow rate of said hot gas and air is about three times the mass flow rate of the gases leaving said outlet nozzle whereby such rotating hot gas and air by direct contact with the interior surface of said single skin annular nose lip raises the temperature of said D-shaped duct to a substantially uniform temperature that is sufficiently high to preclude the formation of ice on the exterior surface of said nose lip while simultaneously precluding the creation of an area of elevated temperature in said nose lip at a location aft of the point of injection of hot gas through said outlet nozzle.

33. A method of providing an anti-icing system for a nose cowl-for an annular air inlet of an aircraft jet engine propulsion system which precludes the creation of a hot spot on such nose cowl in the vicinity of injection of high pressure hot gas into such nose cowl, which method coniprises the steps of:

providing a single skin nose cowl positioned at the leading edge of an air inlet of an aircraft jet engine that is substantially closed by an aft bulkhead to enclose a quantity of air;

providing a source of high pressure hot gas;

introducing said high pressure hot gas into the quantity of air enclosed inlet said nose cowl in a direction substantially tangential to a centerline of said nose cowl to entrain the mass of gas within the nose cowl to create a volume of hot gas and air swirling in a rotational direction around the interior of said nose cowl at a substantially uniform temperature that is sufficiently high to preclude the formation of ice on an exterior surface of said nose cowl during flight; and

creating turbulence and transverse stirring within the flow of high pressure hot gas during its introduction into said quantity of air by introducing such hot gas through an outlet nozzle having a configuration selected from the group consisting of (i) a single elliptically shaped jet nozzle having all outlet area having a horizontal length which is eight times the vertical height of the nozzle, (ii) three elliptically shaped jet nozzles each having an outlet area having a vertical height which is three times the horizontal length for each nozzle, (iii) four elliptically shaped jet nozzles each having an outlet area having a vertical height which is three times the horizontal length for each nozzle, and (iv) four elliptically shaped jet nozzles each having an outlet area having a horizontal length which is three times the vertical height for each nozzle, wherein said jet nozzle or nozzles are oriented to eject said hot gas at high velocity in a direction substantially tangential to a centerline of said annular nose cowl to thereby enhance the commingling of said hot gas and said quantity of air to preclude the creation of an area of elevated temperature on said nose cowl at a position aft of the point of introduction of said hot gas.

34. An anti-icing apparatus comprising:

a substantially closed annular nose cowl comprising an exterior surface and an interior surface and capable of being positioned at the leading edge of an inlet of an aircraft jet engine propulsion system;

at least one conduit comprising an outlet end coupled to the nose cowl, wherein the at least one conduit is capable of being coupled to a source of high pressure hot gas; and

an outlet nozzle provided on the outlet end of the conduit, the outlet nozzle having a configuration selected from the group consisting of (i) a single elliptically shaped jet nozzle having an outlet area having a horizontal length which is eight times the vertical height of the nozzle, (ii) three elliptically shaped jet nozzles each having an outlet area having a vertical height which is three times the horizontal length for each nozzle, (iii) four elliptically shaped jet nozzles each having an outlet area having a vertical height which is three times the horizontal length for each nozzle, and (iv) four elliptically shaped jet nozzles each having an outlet area having a horizontal length which is three times the vertical height for each nozzle, wherein said jet nozzle or nozzles are oriented to eject said hot gas at high velocity in a direction substantially tangential to a centerline of said annular nose cowl.