Hot air injection for swirling rotational anti-icing system

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.

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.

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.

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.

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.

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.

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.