In gas turbine engines, it is necessary to protect exhaust ducts with an insulating shield in order to prevent heated core gases from damaging the exhaust ducts. Typically, exhaust ducts are made from titanium-based alloys and may have temperature limits of approximately 300° F. or about 148.9° C. Exhaust gases, however, reach much higher temperatures. It is, therefore, necessary to line exhaust ducts with a material that is capable of withstanding the peak temperatures of the core gases and that prevents the exhaust duct from reaching its temperature limitations. Exhaust duct liners are typically made from nickel-based alloys, which have temperature limits of approximately 700° F. or about 371.1° C. In order to alleviate some of the heat from the exhaust gases imparted to the liner, cooling air is passed between the exhaust duct and liner.
In one exemplary embodiment, a method for cooling a rotatable nozzle includes rotating a curved seal about a seal land while maintaining contact therewith. Cooling air is directed through a first diffusion hole in the curved seal to cool the nozzle if the rotatable curved seal is in a first position where higher heat is encountered. Cool air is directed through a second diffusion hole in the curved seal to cool the nozzle if the rotatable curved seal is in a first position where higher heat is encountered and if in a second position where relatively lower heat is encountered.
In a further embodiment of any of the above, cooling air is directed into a first chamber in the curved seal and cooling air is directed into a second chamber in the curved seal.
In a further embodiment of any of the above, cooling air is directed from the first chamber through the first diffusion hole in the curved seal if the curved seal is in the first position. Cooling air is directed from the second chamber through the second diffusion hole in the curved seal if the curved seal is in the first position and in the second position.
In a further embodiment of any of the above, the curved seal includes an inner liner and an outer liner. The first diffusion hole and the second diffusion hole are located in the outer liner.
In a further embodiment of any of the above, the first diffusion hole and the second diffusion hole are located in a curved portion of the outer liner.
In a further embodiment of any of the above, a separator plate divides the first chamber from the second chamber.
In a further embodiment of any of the above, the inner liner is in register with the outer liner.
In a further embodiment of any of the above, the first diffusion hole is located axially forward of the second diffusion hole relative to a longitudinal axis of the nozzle.
In a further embodiment of any of the above, cooling air is directed into the first chamber through a first set of infusion holes. Cooling air is directed into the second chamber through a second set of infusion holes.
In a further embodiment of any of the above, cooling air is directed from the first chamber through the first diffusion hole in the curved seal if the curved seal is in the first position. Cooling air is directed from the second chamber through the second diffusion hole in the curved seal if the curved seal is in the first position and in the second position.
In a further embodiment of any of the above, first set of infusion holes are located axially forward of the second set of infusion holes relative to a longitudinal axis of said nozzle.
The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.
Referring now to
An actuator 25 drives a linkage 30 to move the nozzle 10 between various positions as shown in
Referring now to
A separator plate 71 is disposed between the inner liner 55 and the outer liner 60 to create a first chamber 65 and a second chamber 70. The inner liner 55 has a first set of infusion holes 75 and a second set of infusion holes 80. The first set of infusion holes 75 meters air to the first chamber 65. The second set of infusion holes 80 in the inner liner 55 feed the second chamber 70. The outer liner 60 has a first set of diffusion holes 85 and a second set of diffusion holes 90. The first set of diffusion holes 85 expels air from chamber 65 and the second set of diffusion holes 90 in the outer liner 60 diffuse air from the second chamber 70 from the cooling liner 53.
Air expelled from the first set of diffusion holes 85 of the outer liner 60 and the second set of diffusion holes 90 in the outer liner 60 travel along the convergent liner 95. The plenum 40 also delivers air through a divergent supply nozzle 100 to travel along the convergent flap seal 20 to the opening 22 of the divergent flap seal 15.
Referring now to
Referring to
Rotation of the convergent flap seal 20 rotates the cooling liner 53 to vary line contact with the seal land 45 and open and close portions of or all of the first set of diffusion holes 85 thereby metering cooling air as may be necessary for the convergent liner 95 and the convergent flap seal 20 and the divergent flap seal 15 during differing operation of the engine (not shown).
Traditionally, the inner and outer liners 55, 60 might be made of a scarce columbium alloy (Nb) for its inherent low thermal expansion and its ability to withstand heat. However, columbium alloy has limited strength and is difficult to process. For instance, producing cooling holes in Nb is difficult due to its need to be protected from oxygen exposure. Columbium requires application of protective coatings to survive gas turbine environment, said coatings are expensive and environmentally unfriendly. Additionally any hole or penetration in Nb must be produced prior to coating, hence producing small diameter/tight tolerance features are not feasible. By utilizing the designs disclosed herein, secondary cooling air is distributed throughout the exposed curved body 61 of cooling liner 53. The first and second sets of diffusion holes 85, 90 and the first and second sets of infusion (or metering) holes 75, 80 in the inner liner 55, actively meter secondary air flow to coincide with thermal gradients needed for various positions of the divergent flap seal 15 and the convergent flap seal 20. As a result, less expensive and more available materials can be used to create the inner liner 55 and the outer liner 60 rather than columbium alloy. For example, a 625 nickel alloy steel (AMS 5599) may be used.
Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.
This disclosure is a divisional of U.S. patent application Ser. No. 13/173,903 filed Jun. 30, 2011.
This invention was made with Government support under Contract No. N00019-02-C-3003 awarded by the Department of the United States Navy. The Government has certain rights in this invention.
Number | Name | Date | Kind |
---|---|---|---|
4000610 | Nash | Jan 1977 | A |
4544098 | Warburton | Oct 1985 | A |
4690329 | Madden | Sep 1987 | A |
4753392 | Thayer | Jun 1988 | A |
5092525 | Roach | Mar 1992 | A |
5101624 | Nash | Apr 1992 | A |
5239815 | Barcza | Aug 1993 | A |
5255849 | Mayer | Oct 1993 | A |
5398499 | Urruela | Mar 1995 | A |
5437411 | Renggli | Aug 1995 | A |
5586431 | Thonebe | Dec 1996 | A |
5680755 | Hauer | Oct 1997 | A |
5720434 | Vdoviak | Feb 1998 | A |
5839663 | Broadway | Nov 1998 | A |
6195981 | Hanley | Mar 2001 | B1 |
6199371 | Brewer et al. | Mar 2001 | B1 |
6301877 | Liang | Oct 2001 | B1 |
6966189 | Lapergue | Nov 2005 | B2 |
7032835 | Murphy | Apr 2006 | B2 |
7377099 | Cowan | May 2008 | B2 |
7581385 | Farah et al. | Sep 2009 | B2 |
7757477 | Kehret | Jul 2010 | B2 |
8205454 | Cowan | Jun 2012 | B2 |
8607574 | Moon | Dec 2013 | B1 |
20040003585 | Allore | Jan 2004 | A1 |
20050005608 | Pancou | Jan 2005 | A1 |
20050161527 | Murphy | Jul 2005 | A1 |
20050235628 | Senile | Oct 2005 | A1 |
20060137324 | Farah | Jun 2006 | A1 |
20070062199 | Cowan | Mar 2007 | A1 |
20080072604 | Swanson | Mar 2008 | A1 |
20090072044 | Kehret | Mar 2009 | A1 |
Number | Date | Country |
---|---|---|
0541346 | May 1993 | EP |
Entry |
---|
European Search Report for European Application No. 12173265.5 dated Apr. 7, 2017. |
Number | Date | Country | |
---|---|---|---|
20180156053 A1 | Jun 2018 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 13173903 | Jun 2011 | US |
Child | 15876602 | US |