The invention is an arrangement to support and retain a metering plate in a turbine engine. More particularly, this invention relates to retaining a metering plate within a trailing edge box without requiring additional fasteners.
Turbine engines may have afterburners, or augmenters, located at the rear of the engine before the exhaust nozzle. Afterburners utilize unused oxygen from the turbine engine to obtain a second combustion. The second combustion provides additional thrust for the turbine engine. An afterburner has a trailing edge box to house a fuel spraybar that sprays fuel to mix with unused oxygen. A metering plate is housed in the trailing edge box to create a pressure drop from the front of the trailing edge box toward a flameholder at the rear of the trailing edge box. The pressure drop creates airflow that causes a cooling air film to develop on a coated surface of the flameholder.
Turbine engines often must meet special requirements. One such special requirement is that all interfaces must be internal to the major components. Due to this requirement packaging for fasteners and other structural parts is difficult. As a result there is little room for fasteners at the rear of the trailing edge box for supporting the metering plate.
Additionally, turbine engines and afterburners are subject to heavy vibrations, which may cause high wear on the engine and afterburner components.
A lighter arrangement to retain a metering plate while providing support to a turbine engine component is needed.
A turbine engine afterburner has trailing edge boxes to house the afterburner components. Each trailing edge box uses a metering plate to create a pressure drop from the front to the rear of the trailing edge box where a flameholder is located. The pressure drop creates a positive pressure flowing out of the flameholder to create a film of cooling air on the surface of the flameholder.
Slots for receiving the metering plate are located in corrugations formed within the trailing edge box. The ends of the metering plate have hooks that correspond to the location of the slots. The hooks are placed within the slots to retain the metering plate. Once in place force is applied to the metering plate as a result of airflow through the trailing edge box.
The metering plate is at an angle to the load placed on the trailing edge box to create pressure on the hooks and retain the metering plate within the slots. The metering plate also adds structural support to the trailing edge box by reinforcing and connecting the walls of the trailing edge box.
Accordingly, the example trailing edge box of this invention retains a metering plate and strengthens the trailing edge box while eliminating the need for metering plate fasteners.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
Referring to
The example trailing edge box 32 is formed of sheet metal. The sheet metal is formed to create corrugations 40 on the internal side of the first wall 42 and the second wall 44 of the trailing edge box 32. The first wall 42 and the second wall 44 are opposing sides of the trailing edge box 32. When the trailing edge box 32 is assembled the corrugations from each side face one another running laterally from an outer case edge 39 toward an inner case edge 41. The corrugations 40 may be formed as one piece with the first wall 42 and the second wall 44 or may be separate pieces of sheet metal which are attached to the first wall 42 and the second wall 44.
A metering plate 62 fits within slots 66 in corrugations 40 on the first wall and slots 72 formed in the corrugations 40 of the second wall 44. When assembled the metering plate 62 is generally parallel to the flameholder 43. Exhaust holes 54 in the metering plate 62 and flameholder 43 allow exhaust gases to exit the trailing edge box. The flameholder 43 forms a wall at the trailing edge of the trailing edge box 32. The flameholder 43 assists in combustion by controlling the rate at which air flows through the trailing edge box 32, thereby providing for the desired second combustion.
A portion of the metering plate 62 has been removed to show the corrugations 40 on the first wall 42 and the corrugations 40 on the second wall 44. Slots 66 and 72 are formed in the straight sides 46 of the corrugations 40 for receiving the metering plate 62.
As a result of the angular sides 46 of the corrugations 40, the metering plate 62 is at an angle to the load L placed on the trailing edge box 32. The load L on the trailing edge box 32 creates pressure on the hooks 74 of the metering plate 62 to retain the metering plate 62 within the slots 66 and 72. The metering plate 62 also adds structural support to the trailing edge box 32 by reinforcing and connecting the first side 42 with the second side 44.
Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
The US Government may have certain rights in this invention in accordance with Contract Number N00019-02-C-3003 awarded by the United States Navy.