Passive control of hot air injection for swirling rotational type anti-icing system
First Claim
1. An anti-icing system for a nose cowl for an annular inlet of an aircraft jet engine propulsion system for an aircraft which comprises:
- 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 means coupled to the source of high pressure hot gas and having an outlet end extending into said nose cowl;
at least one outlet nozzle provided on the outlet end of said conduit means, said outlet nozzle being provided with circumferentially arranged means extending aft from said outlet nozzle and extending into the flow of hot gas issuing from said nozzle to create longitudinal vortices and transverse stirring in the hot gas flow, said outlet nozzle being oriented to eject said hot gas at high velocity in a direction substantially tangential to a centerline of said annular nose cowl, wherein said circumferentially arranged means extending from the outlet end of the conduit means includes a plurality of circumferentially arranged tabs that are canted inwardly into the flow of hot gas issuing from the nozzle, and whereby the turbulent high velocity hot gas flow issuing from said nozzle entrains the 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 single skin 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 nose cowl by the grazing flow of ambient air when the aircraft is in flight while also precluding the creation of an area of elevated temperature in said nose cowl at a location downstream of said outlet nozzle.
1 Assignment
0 Petitions
Accused Products
Abstract
An improved anti-icing system for a nose cowl of an aircraft jet engine. An improved injection nozzle is provided to passively 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 skin of the nose cowl to rise sufficiently to preclude the formation of ice thereon during flight. A plurality of spaced circumferentially arranged tab members, that are preferably triangularly shaped, are canted inwardly slightly to create large scale longitudinal vortices and transverse stirring during the introduction of hot gas and thereby 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 downstream of the position of the injection nozzle under certain severe design conditions.
-
Citations
19 Claims
-
1. An anti-icing system for a nose cowl for an annular inlet of an aircraft jet engine propulsion system for an aircraft which comprises:
-
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 means coupled to the source of high pressure hot gas and having an outlet end extending into said nose cowl;
at least one outlet nozzle provided on the outlet end of said conduit means, said outlet nozzle being provided with circumferentially arranged means extending aft from said outlet nozzle and extending into the flow of hot gas issuing from said nozzle to create longitudinal vortices and transverse stirring in the hot gas flow, said outlet nozzle being oriented to eject said hot gas at high velocity in a direction substantially tangential to a centerline of said annular nose cowl, wherein said circumferentially arranged means extending from the outlet end of the conduit means includes a plurality of circumferentially arranged tabs that are canted inwardly into the flow of hot gas issuing from the nozzle, and whereby the turbulent high velocity hot gas flow issuing from said nozzle entrains the 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 single skin 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 nose cowl by the grazing flow of ambient air when the aircraft is in flight while also precluding the creation of an area of elevated temperature in said nose cowl at a location downstream of said outlet nozzle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. An anti-icing system for annular aircraft jet engine housings which comprises:
-
a substantially annular single skin housing 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 housing;
a hot, high pressure gas region of a jet engine;
at least one conduit means adapted to carry hot gas from said region having a temperature of about 500 to 1000 degrees F. and a mass flow rate of up to 1.5 lbm/sec., said at least one conduit means having an outlet end extending into said housing through said bulkhead;
at least one outlet nozzle provided on said outlet end of each said conduit means, each outlet nozzle being oriented to eject said hot gas at a high velocity in a direction substantial tangential to the centerline of said annular nose cowl and being provided with circumferentially arranged means extending aft from said outlet nozzle and into the flow of hot gas issuing from said nozzle to create longitudinal votices and traverse stirring in said hot gas slow, wherein said circumferentially arranged means extending from the outlet end o the conduit means includes a plurality of circumferentially arranged tabs that are canted inwardly into the flow of hot gas issuing from the nozzle. - View Dependent Claims (12, 13, 14, 15, 16)
-
-
17. 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 cowl that comprises the steps of:
-
providing a single skin nose cowl positioned at the leading edge of an air inlet having an acoustically treated inner barrel 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 quantity of gas within the nose cowl to create a volume of mixed 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
to create longitudinal vortices and transverse stirring within the flow of high pressure hot gas during its introduction into said quantity of air and thereby enhance the commingling of injected said hot gas and hot 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 and permit reduction of the size of the nose cowl and a concomitant increase in the longitudinal size of said acoustically treated inner barrel, wherein said circumferentially arranged means extending from the outlet end of the conduit means includes a plurality of circumferentially arranged tabs that are canted inwardly into the flow of hot as issuing from the nozzle. - View Dependent Claims (18, 19)
-
Specification