KR20080034086A - Fan case reinforcement in a gas turbine jet engine - Google Patents

Abstract

Described is reinforcement of a fan case in a gas turbine jet engine. In one embodiment, a containment ring and a hear resistance ring are shrink interference fit on the inside diameter of the fan case, the containment ring where the large fan blades turn, and the heat resistance ring where heated air from backfiring heats up the fan case. In one example, the containment ring is made of a sue alloy to provide added strength to the fan case should a fan blade break, containing the fan blade within the fan case. Also, the containment ring may extent forward of at least the leading edge of each fan blade and aft of at least the trailing edge of each fan blade. The heat resistance ring is made of titanium or other suitable material. Additionally, one or more stiffener rings may be shrink interference fit on the outside diameter of the fan case. The containment ring and stiffener rings can reduce the flight weight of the fan case and lower the material costs, while increasing the containment strength of the fan case. Other embodiments are described and claimed.

Description

FAN CASE REINFORCEMENT IN A GAS TURBINE JET ENGINE}

Related Applications

The present invention discloses US patent application Ser. No. 10 / 947,923 (filed September 23, 2004; titled invention: Method and Apparatus for Improving Heat Resistance and Fan Case Blockage in Gas Turbine Jet Engines). And part of the pending PCT International Patent Application No. PCT / 2005/33564, which is part of the Fan Case Containment and Heat Resistance in a Gas Turbine Jet Engine.

In a full test of a gas turbine jet engine, the fan blade is intentionally released from the hub at full engine rotational speed by an explosion bolt located at the base of the fan blade. These tests are used to demonstrate the performance of the engine carcass to contain the impact of the fan blades and to handle the generated out-of-balance forces. These shocks are absorbed as vibrations through the fan case containment system surrounding the engine. Such a fan case is an element in a fan case containment system and is usually the heaviest component within a gas turbine jet engine due to its size and strength conditions that the fan case may possess for containment purposes. In gas turbine jet engines that are prone to backfiring, heated air moves rearward from the combustor to the fan area, raising the temperature inside the fan case and raising the fan case temperature. This higher temperature may be a factor in determining what material the fan case should be made of. A need in the art is to use a fan case material that can maintain or reduce the weight of the fan case while at the same time maintaining or improving the fan case containment strength and withstanding the pan case temperature described above.

1 is a schematic diagram of the overall structure of a conventional gas turbine jet engine with a typical fan case of the prior art.

2 is a cross-sectional view of the forging for a typical fan case of the prior art.

3 is a cross-sectional view of the forging for a fan case in an embodiment of the present invention.

4 is a machine having two stiffener rings (FIGS. 5A, 5B and 6A, 6B) and a containment ring (FIGS. 7A, 7B) shrink-fit into the fan case of FIG. 3 of an embodiment of the present disclosure. Cross section of the finished fan case.

5A is a cross sectional view of the forging for the first stiffener ring for the fan case of FIG. 3 of an embodiment of the present disclosure.

FIG. 5B illustrates the first stiffener ring of FIG. 5A fitted directly to the fan case of FIG. 3 of an embodiment of the present disclosure.

6A is a cross sectional view of the forging for the second stiffener ring for the fan case of FIG. 3 of an embodiment of the present disclosure.

FIG. 6B shows the second stiffener ring of FIG. 6A fitted directly to the fan case of FIG. 3 of an embodiment of the present disclosure.

FIG. 7A is a cross sectional view of the forging for a containment ring for the fan case of FIG. 3 herein. FIG.

FIG. 7B shows the containment ring of FIG. 7A fitted directly to the fan case of FIG. 3 of an embodiment of the present disclosure.

8 is a schematic diagram of airflow through a typical gas turbine jet engine.

9 is a schematic diagram of airflow through a typical gas turbine jet engine where backfire is likely to occur.

10 is a cross sectional view of forging for a fan case for improved thermal resistance in embodiments herein.

FIG. 11 is a cross-sectional view of a mechanically finished fan case having a ring of heat resistant material shrink-fit into the fan case of FIG. 10 in an embodiment of the present disclosure.

12 is a schematic cross-sectional view of a fan case having an inner containment ring of embodiments of the present disclosure.

13 is a schematic cross-sectional view of a fan case having an outer containment ring of embodiments of the present disclosure.

14 is a cross-sectional view of an alternative embodiment mechanically finished fan case with two stiffener rings and containment rings shrink-fit to the fan case with a pan case disposed therebetween.

FIG. 15 is a schematic cross-sectional view of the fan case of FIG. 14 with an inner containment ring facing the outer stiffener ring.

16 is a schematic diagram showing a blade collision containment area of the fan case of the embodiment of the present description.

17 is a schematic cross-sectional view of the fan blade of the fan case of FIG. 16.

Referring to the drawings, like reference numerals and designations indicate structural and / or functionally similar elements, and FIG. 1 shows a schematic diagram of the overall structure of a conventional gas turbine jet engine with a typical fan case of the prior art. do. Referring again to FIG. 1, the gas turbine jet engine 100 includes a fan 102 having a plurality of fan blades 104 embedded inside the fan case 106. The fan blade 104 rotates on the axis of rotation along the centerline 107 to provide suction, the thrust booster 108 supplies inlet air to the high pressure compressor rotor 110 and the blades and stators attached thereto. They force air to the combustor 112 and raise the pressure and temperature of the incoming air. The high pressure turbine rotor 114 and accompanying blades and stators are embedded inside the high pressure turbine case 116. The low pressure turbine rotor 118 and accompanying blades and stators are embedded within the low pressure turbine case 120. The low pressure turbine rotor 118 and its accompanying blades and stators extract energy from the high pressure, high velocity gas flow flowing from the combustor 112 and transfer energy to the low pressure turbine shaft 122, which in turn is a fan 102. ) And provide most of the propulsion for the gas turbine jet engine 100.

Figure 2 shows a cross sectional view of a forging for a typical fan case of the prior art. After machining, the fan case forging 200 yields a fan case 202 with outlines in dashed lines. In this example, the pan case forging 200 is forged with one piece of titanium cylinder. The operating temperature and rod characteristics of the particular gas turbine jet engine in which the fan case 202 is constructed may require a fan case 202 made of titanium. The forging weight of this particular pan case forging 200 is approximately 3,347 pounds. After machining, the fan case 202 has a flight weight of approximately 975.2 pounds. On gas turbine jet engines, the fan case can also be made of aluminum, steel or composite material. The composite material typically includes a core material, a reinforcing material and a resin binder. Core materials typically include wood, foams and honeycombs. Reinforcing materials include glass fibers, carbon fibers, and Kevlar ^® . Resin components usually include polyesters, vinyl esters and epoxies. As technology advances, and as the temperature in gas turbine jet engines rises, aluminum cases are often wrapped in Kevlar ^® to provide added strength for fan case containment purposes. For excessively higher operating temperatures not suitable for aluminum or steel, titanium, which may be wrapped with Kevlar ^® , is used if additional strength is required.

Structural shapes of the machined fan case 202 include a first stiffener ring 204 and a second stiffener ring 206. These two stiffener rings help prevent the fan case 202 from ellipsoidal under load and temperature conditions experienced during engine operation. Accessory flange 208 will have a through-drilled hole from which various engine components, such as gear boxes, tubes, wiring, and the like, hang. First containment ring 210 surrounds the exterior of fan case 202 and provides additional strength for fan case containment. The second containment ring 212 surrounds the interior of the fan case 202 and also provides additional strength for fan case containment. The section of the fan case 202 between the first containment ring 210 and the second containment ring 212 may be moved away from the hub if the fan blade 104 (FIG. 1) probably collides. This is the area to exit. Due to the size of the fan blade 104, which is typically the largest fan blade in a gas turbine jet engine, this section of the fan case 202 is often exceptionally rigid. Thus, the first containment ring 210 and the second containment ring 212 provide additional rigidity.

3 shows a cross section of a forging for a fan casing in an embodiment of the present disclosure. Referring again to FIG. 3, the fan casing herein can replace the fan case 202 for use within the same gas turbine jet engine, for which the fan case 202 is an alternative to existing engines. Anywhere in retrofit or in a newly manufactured engine. The properties herein are applicable to fan cases of gas turbine jet engines used in a variety of applications where fans draw air and generate propulsion. These applications include the aviation industry, amphibian and others. The fan case forging 300 obtains a fan case 302 as shown in dashed lines after machining. In this example, fan case forging 300 is also forged with one piece of titanium cylinder. In this example, the pan case forging 300 has a simpler shape that simplifies the forging process, but it is understood that this shape may vary depending on the particular application. In this embodiment, the forging weight for the pan case forging 300 is approximately 2,595 pounds and 752 pounds lighter than the pan case forging 200. After machining, the pan case 302 has a flight weight of approximately 751.3 pounds and is 223.9 pounds lighter than the pan case 202. The material, weight, and characteristics of the pan case forging 300 may vary depending on the particular application.

Structural features of the machined fan case 302 include a first stiffener ring notch 304 and a second stiffener ring notch 306 located in the central portion of the fan case 302. Two stiffener rings from two additional forgings (FIGS. 5A, 5B, 6A and 6B) prevent the fan case 302 from ellipsing under the load and temperature conditions experienced during engine operation. Will be positioned within the first stiffener ring notch 304 and the second stiffener ring notch 306 (see FIG. 4). Depending on the configuration of the particular fan case, to some extent stiffener ring notches may be used, and these stiffener ring notches may be located at various locations on the surface of the fan case. While stiffener rings 502 and 602 are shown to be located on the outer surface of fan case 302, it is understood that one or more stiffener rings may be installed on the inner surface of the fan case, depending on the application. The accessory flange 308 facing the rear end of the fan case 302 has a perforated hole or other attachment surface formed thereon, with various engine components such as gearboxes, tubes, wiring, etc. Supported by).

The containment ring notch 310 surrounds the interior of the fan case 302 around the front end. The containment ring (FIGS. 7A and 7B) from the additional forging will be located in the containment ring notch 310. FIG. 12 shows a schematic cross-sectional view of a fan case 302 fitted with a containment ring 702 located in an containment ring notch 310 therein. The section of the fan case 302 spanning the containment ring notch 310 is the area where the fan blades move away from the hub if the fan blades 104 (FIG. 1) possibly collide. In this embodiment the section of this fan case 302 is relatively rigid, and the containment ring from further forging machined into a predetermined shape conforming to the containment ring notch 310 provides additional strength and containment function. to provide. The fan case 302 is not a structure comparable to the first containment ring 210, which may be omitted from the fan case 302 herein due to the additional strength provided by the containment ring 702. It is understood that in other embodiments a second or additional containment ring may be added depending on the particular application.

5A shows a cross section of a forging for a first stiffener ring for the fan casing of FIG. 3 of an embodiment of the present disclosure, and FIG. 5B shows a shrinkage interference fit directly to the fan casing of FIG. 3 of an embodiment of the present disclosure. The first stiffener ring of FIG. 5A is shown when shrink interference fit. Referring again to FIGS. 5A and 5B, after being machined into a predetermined shape consistent with the first stiffener ring notch 304, the first stiffener ring forging 500 is shown with dashed outlines in FIG. 5A. A first stiffener ring 502 is obtained. In this example, the first stiffener ring forging 500 is forged with one piece of aluminum ring. The forging weight for the first stiffener ring forging 500 is approximately 154 pounds. After machining, the first stiffener ring 502 has a flight weight of approximately 41 pounds.

In this example, the first stiffener ring 502 manufactured separately from the fan case 302 is shrink-tight fit into the first stiffener ring notch 304. At ambient temperature, the inner diameter of the first stiffener ring 502 is somewhat smaller than the outer diameter of the first stiffener ring notch 304. The first stiffener ring 502 is heated, thereby expanding the first stiffener ring 502, increasing the inner diameter to a diameter larger than the outer diameter of the first stiffener ring notch 304, and the first ring gap 504. And allow the first stiffener ring 502 to be positioned as shown in the first stiffener ring notch 304. In this position, the first stiffener ring 502 can be cooled, thereby shrinking its diameter and placing itself around the first stiffener ring notch 304. At ambient temperature, the fan is driven by the first stiffener ring 502 due to the first stiffener ring 502 which attempts to return to a smaller inner diameter but fails to do so due to the larger outer diameter of the first stiffener ring notch 304. The radial circumferential compressive force is applied to the case 302 to cause shrinkage due to an interference fit, and the circumferential tensile force is applied to the first stiffener ring 502 by the fan case 302. In one embodiment, the radial compressive force can be centered on the axis of rotation formed by the centerline 107. In addition, the radial compressive force acts continuously around the entire circumference of the first stiffener ring 502 without interruption.

FIG. 6A shows a cross section of a forging for a second stiffener ring for the fan casing of FIG. 3 of an embodiment of the present description, and FIG. 6B shows a shrink-tight fit directly to the fan casing of FIG. 3 of an embodiment of the present disclosure. The second stiffener ring of FIG. 6A is shown. Referring again to FIGS. 6A and 6B, after being machined into a predetermined shape to conform to the second stiffener ring notch 306, the second stiffener ring forging 600 is shown with dashed outlines in FIG. 6A. A second stiffener ring 602 is obtained. In this example, the second stiffener ring forging 600 is forged with one piece of aluminum ring. The forging weight for the second stiffener ring forging 600 is approximately 148 pounds. After machining, the second stiffener ring 602 has a flight weight of approximately 40.6 pounds.

In this example, a second stiffener ring 602 manufactured separately from the fan case 302 is shrink-fitted into the second stiffener ring notch 306. At ambient temperature, the inner diameter of the second stiffener ring 602 is somewhat smaller than the outer diameter of the second stiffener ring notch 306. The second stiffener ring 602 is heated, thereby expanding the second stiffener ring 602, increasing the inner diameter to a diameter larger than the outer diameter of the second stiffener ring notch 306, and the second ring gap 604. And allow the second stiffener ring 602 to be positioned as shown in the second stiffener ring notch 306. In this position, the second stiffener ring 602 can be cooled, thereby shrinking its diameter and placing itself around the inside of the second stiffener ring notch 306. At ambient temperature, the fan is driven by the second stiffener ring 602 due to the second stiffener ring 602 that attempts to return to a smaller inner diameter but fails to do so due to the larger outer diameter of the second stiffener ring notch 306. A radial circumferential compressive force is applied to the case 302 to cause shrinkage due to an interference fit, and a circumferential tensile force is applied to the second stiffener ring 602 by the fan case 302. In one embodiment, the radial compressive force can be centered on the axis of rotation formed by the centerline 107. In addition, the radial compressive force acts continuously around the entire circumference of the second stiffener ring 602 without interruption. Further, in one embodiment, each stiffener ring may be a continuous, seam-free member of a solid, monolithic or one piece, forged or machined in a closed loop shape. In another embodiment, the stiffener ring can be manufactured by using an open loop-shaped member to join the ends together, for example by welding, to form a closed loop shape.

It is understood that the stiffener ring may be located at different locations in the fan case depending on the application. It is also understood that the size, dimensions, shape, material and gaps may vary depending upon the particular application. It is understood that stiffener rings, such as the first stiffener ring 502, may not engage 100% of the circumference of the outer surface of the fan case 302 due to various factors such as nonperfect roundness. For example, the first stiffener ring 502 may contact 70% of the circumference of the outer surface of the fan case 302, but the amount of such contact may vary depending on the particular application. Nevertheless, when the first stiffener ring 502 is shrink-fitted with the fan case 302, the first stiffener ring 502 has a length around the inner circumferential surface of the first stiffener ring 502. Consider the application of radial compressive forces. In some applications, it is also understood that it may be appropriate to provide the liner material between the shrinkage interference fit of the stiffener ring to the fan case such that the compressive force between the stiffener ring and the pan case is transmitted through the liner material. In one embodiment, the liner material may be made of a compressible material. It is understood that in other embodiments the liner material may have relatively hard or other physical properties.

FIG. 7A shows a cross section for a containment ring for the fan case of FIG. 3 in an embodiment of the present disclosure, and FIG. 7B shows a containment of FIG. 7A that shrink-fits directly to the fan casing of FIG. 3 of an embodiment of the present disclosure. Show the ring. Referring again to FIGS. 7A and 7B, after being machined into a predetermined shape that matches the containment ring notch 310, the containment ring forging 700 is a containment ring 702 with an outline outlined in FIG. 7A. ). In this example, the containment ring forging 700 is forged into a ring of nickel-based superalloy such as Inconel 718 in one piece. The forging weight for the containment ring forging 700 is approximately 467 pounds. After machining, containment ring 702 has a flight weight of approximately 138.1 pounds. It is understood that the containment ring may be located at different locations in the fan case depending on the application. It is also understood that the size, dimensions, shape, material and gaps may vary depending upon the particular application. For example, containment ring 702 may be made of other superalloys, steel, titanium, or other suitable material for sealing the blades. Further, in one embodiment, each stiffener ring may be a continuous, seam free member of a solid, monolithic or one piece, forged or machined in a closed loop shape. In another embodiment, the stiffener ring can be made by joining the ends together by welding, for example, to form a closed loop shape using an open loop-shaped member.

In this example, a containment ring 702 manufactured separately from the fan case 302 is shrink-fitted into the containment ring notch 310. At ambient temperature, the outer diameter of containment ring 702 is somewhat smaller than the inner diameter of containment ring notch 310. The fan case 302 is heated, thereby expanding the fan case 302, increasing the inner diameter to a diameter larger than the outer diameter of the containment ring 702, generating a containment ring gap 704, and a containment ring 702. ) May be positioned as shown in containment ring notch 310. In this position, the fan case 302 can be cooled such that the diameter shrinks and the containment ring 702 itself can be positioned around the inside of the containment ring notch 310. At ambient temperature, due to the fan case 302 attempting to return to a smaller inner diameter but failing to do so due to the larger outer diameter of the containment ring 702, the radial circumference of the containment ring 702 by the fan case 302. As a compressive force is applied, shrinkage due to an interference fit occurs, and a circumferential tensile force is applied to the fan case 302 by the containment ring 702. In one embodiment, the radial compressive force may be centered on the axis of rotation formed by the centerline 107 as schematically indicated by the arrows in FIG. 12. In one embodiment, the radial compressive force acts continuously around the entire circumference of the containment ring notch 310 of the fan case 302 without interruption. It is understood that a variety of factors, such as incomplete roundness, may prevent a containment ring such as containment ring 702 from engaging 100% of the circumference of the inner surface of fan case 302. For example, the containment ring 702 may contact 70% of the circumference of the inner surface of the fan case 302, but the amount of such contact may vary depending on the particular application. Nevertheless, when the fan case 302 is shrink-fitted to the containment ring 702, the fan case 302 applies radial compressive force along the length of the circumference of the inner circumferential surface of the containment ring notch 310. Consider that. In some applications, it is also understood that it may be appropriate to provide the liner material between the shrinkage interference fit of the containment ring to the fan case such that the compressive force between the containment ring and the pan case is transmitted through the liner material. In one embodiment, the liner material may be made of a compressible material. It is understood that in other embodiments the liner material may have relatively hard or other physical properties.

For fan cases made of composite material, containment ring 702 is cooled by liquid nitrogen to reduce its outer diameter, create containment ring gap 704, and containment ring 702 is containment ring notch 310. To be positioned as shown in FIG. In this position, containment ring 702 can be warmed to ambient temperature, increased in diameter and positioned itself circumferentially into containment ring notch 310. At ambient temperature, due to the containment ring 702 attempting to return to a larger outer diameter but failing to do so due to the smaller inner diameter of the containment ring notch 310, a radial circumference to the containment ring 702 by the fan case 302. The compression force is applied to create an interference fit, and the circumferential tensile force is applied to the fan case 302 by the containment ring 702. The cooling of the containment ring 702 and the heating of the fan case 302 may also result in a shrink fit in certain situations.

In one embodiment of the present disclosure, the containment ring notch 310 is formed by a reverse taper such that the point A of the inner diameter of the fan case 302 is smaller than the point B of the inner diameter of the fan case 302. Machined on the perimeter. Such inverse taper may vary from fan case to fan case, ranging from an angle greater than 0 ° to the cylindrical case to an appropriate angle that depends on the particular shape of the conical pan case. The containment ring 702 is machined circumferentially on its outer surface to conform to this same reverse taper. Although the containment ring 702 is shrink-fit on the fan case 302, this reverse taper may add additional safety to prevent the containment ring 702 from sliding axially on the fan case 302. Can be.

Further, machining of the fan case 302 may be performed in a first direction, such as in the radial direction, and machining for the containment ring 702 in a second direction, such as in the axial direction, substantially perpendicular to the first direction. Can be implemented. Since machining leaves spiral or record continuous grooves on the machining surface, these grooves on each surface are aligned in a cross-hatch fashion with respect to each other, increasing friction between the two surfaces. And reduce the potential for rotation of containment ring 702 within containment ring notch 310. The plurality of grooves on the containment ring 702, which may be made of, for example, nickel-based superalloy, may be, for example, on the containment ring notch 310 of the fan case 302, which may be made of titanium, or another fan case that may be made of steel or aluminum It may be harder than a plurality of grooves in the inside. Alternatively, the containment ring 702 may simply be spot welded at one or more locations to the containment ring notch 310 to prevent the containment ring 702 from rotating in connection with the containment ring notch 310. Or may be bolted to one or more flanges secured to containment ring notch 310. Machining in the cross direction may be appropriately applied or omitted depending on the application.

4 is a machine with two stiffener rings (FIGS. 5A, 5B, 6A and 6B) and a containment ring (FIGS. 7A and 7B) that were shrink fit fitted to the fan casing of FIG. 3 in embodiments herein. A cross sectional view of a finished fan casing is shown. Referring back to FIG. 4, the containment ring 702 can replicate a portion of the structure compared to the second containment ring 212 and utilize the first containment ring 210 in whole or in part depending on the application. Can be removed. By shrink-fitting the containment ring 702 onto the inner diameter of the fan case 302, in contrast to the outside, the harder superalloy containment ring 702 can provide an initial impact surface that breaks the blade. . It may function as a shock absorbing device due to different expansion rates between the two materials of the softer titanium, steel or aluminum fan case 302 on the exterior of the containment ring 702. As the superalloy containment ring 702 begins to move, the containment ring 702 can push out the pan case 302 of titanium, steel or aluminum having a different coefficient of expansion. It is like having two nets close to each other. The superalloy containment ring 702 may be subjected to an initial strike and a portion of the force is transferred to a pan case 302 of titanium, steel or aluminum, such as a shock absorber.

The first stiffener ring 502 and the second stiffener ring 602 are shown to be carefully positioned within the first stiffener ring notch 304 and the second stiffener ring notch 306. The first stiffener ring 502 and the second stiffener ring 602 reinforce the fan case 302 to prevent the engine from being deformed or elliptical during operation under temperature and load conditions.

In this particular example, Table 1 below shows a comparison of the forging weight, flight weight and price of a conventional fan case 202 relative to the fan case 302 herein.

Part / Material Forging weight (lbs) Flight weight (lbs) Cost / lb Total cost Fan case (202) titanium 3,347.0 975.2 $ 8.00 $ 26,776.00 Fan case (302) titanium 2,595.0 751.3 $ 8.00 $ 20,760.00 First stiffener ring (502) aluminum 154.0 40.5 $ 1.50 $ 231.00 Second stiffener ring (602) aluminum 148.0 40.6 $ 1.50 $ 222.00 Containment Ring (702) Inconel (718) 467.0 138.1 $ 7.00 $ 3,269.00 sum 3,364.0 970.5 $ 7.28 $ 24,482.00 Savings -17.0 4.7 $ 0.72 $ 2,294.00

Thus, in this example, the flight weight is less than 4.7 pounds, even if the forging weight is 17 pounds or more. In addition, the average cost per pound of material of the fan case 302 is $ 0.72 / lbs less than the fan case 202, resulting in a total savings of $ 2,294.00. Also, in this example, fan case 302 is considerably more rigid than fan case 202.

In other applications, the savings may be greater. For example, for a fan case that requires Kevlar® reinforcement, the fan case herein can be more rigid enough to eliminate the need for Kevlar® reinforcement, resulting in substantial savings in both material and labor costs. . This specification may also be used with Kevlar® reinforcements to achieve higher fan case strength. For gas turbine jet engines that currently use steel or titanium for fan cases, the present specification may allow aluminum to replace steel or titanium, and is required for containment by containment rings of nickel-based superalloys or other suitable materials. Strength is provided. The same volume of aluminum or titanium is about 30% to 55% of the weight of the same volume of steel, which can result in substantial savings. This weight saving is manifested in increased cargo transport capacity or reduced fuel consumption or a combination of both.

In the field of gas turbine jet engines, the trend is to make fan blades longer to increase trust. The tip of the fan blade can rotate at supersonic speed, while the base of the fan blade rotates at subsonic speed. This can cause harmonic vibrations in the blades that cause the tips of the blades to break. To solve this problem, instead of manufacturing a straight fan blade, the blade is further shaped like a wide paddle. This wider and longer blade is an additional mass that must be included inside the fan casing. In addition, as the engine improves more efficiently, the engine will operate at hotter temperatures, potentially adding more difficulty to containment problems. This detailed description is believed to not only help significantly meet the challenges for greater fan case containment strength and potentially lower weight and lower cost, but also provide additional properties in addition to or instead of depending on the particular application. .

8 shows a schematic of the airflow through a typical gas turbine jet engine. Referring again to FIG. 8, for a gas turbine jet engine that is not easily susceptible to backfire, airflow 824 flows into fan case 806 and into booster 808. The high pressure compressor rotor 810 compresses the airflow 824 as it enters the combustor 812. After passing through the high and low pressure turbines, airflow 824 flows outward from the rear of the gas turbine jet engine 800. The heated air stream 824 in the combustor 812 moves outwards through the rear of the gas turbine jet engine 800.

9 shows a schematic of a typical gas turbine jet engine vulnerable to backfire. Referring back to FIG. 9, in contrast to FIG. 8, the gas turbine jet engine 900 has a fan 902 through which the heated air 926, represented by a dotted line, which is part of the airflow 924, passes through the gas turbine jet engine 900. It is vulnerable to backfire that causes it to flow back into the domain of. The heated air 926 causes the temperature inside the fan case 906 to rise, which in turn also raises the temperature of the fan case 906 itself in the area indicated by the area 928. Of course, temperature is one of the major factors in determining what material the fan case 906 should be made of. If the fan case temperature exceeds 800 degrees, aluminum is no longer suitable. More expensive heat resistant materials such as steel, titanium, or superalloys may be suitable.

10 shows a cross section of a forging for a fan case for improved heat resistance in an embodiment of the present description. Referring back to FIG. 10, it is believed that for gas turbine jet engines that are vulnerable to backfire, the fan case of the present description can be used to neutralize thermal issues and improve the thermal resistance of the fan case 1002. The fan case forging 1000 is similar to the fan case forging 300 shown in FIG. 3. Machining the fan case forging 1000 yields a fan case 1002 shown in dashed lines similar to the fan case 302. In this example, the pan case forging 1000 is forged from one piece of aluminum.

Structural characteristics of the machined fan case 1002 are similar to those shown in FIGS. 3 and 4, but with a heat resistant ring that surrounds the interior of the fan case 1002 around the position formed in the region 928 of FIG. 9 as a whole. It also includes a notch 1012. The ring of heat resistant material is located in the heat resistant ring notch 1012 in the present embodiment in a shrinkage inhibited fit. The section of the fan case 1002 spanning the heat resistant ring notch 1012 is an area where heated air from backfire can cause elevated fan case temperatures.

It is understood that the heat resistant ring may be located at different locations in the fan case, depending on the application. It is also understood that the size, dimensions, shape, material and gap may vary depending on the particular application.

As described above, machining of the fan case 1002 may be performed in a first direction, such as radially, and machining of the heat resistant ring 1112 may be performed in a second, such as an axial direction, substantially perpendicular to the first direction. Direction can be implemented. Since the machining can leave spiral or recorded continuous grooves on the machining surface, the grooves on each machining surface can be aligned in a cross-hatch fashion with respect to each other, Increases friction between the machining surfaces and reduces the potential for rotating the heat resistant ring 1112 inside the heat resistant ring notch 1012. The plurality of grooves on the heat resistant ring 1112 made of titanium may be harder than the plurality of grooves on the heat resistant ring notch 1012 of the fan case 1002 made of aluminum. Titanium grooves pit into softer aluminum grooves. Alternatively, the heat resistant ring 1112 may be simply spot welded at one or more locations to the heat resistant ring notch 1012 or bolted to one or more flanges secured to the heat resistant ring notch 1012, such that the heat resistant ring 1112 Rotation is prevented with respect to this heat resistant ring notch 1012. In this case, machining in the cross direction may not be necessary or may be applied in addition thereto.

FIG. 11 illustrates a cross section of a machined finished fan case having a ring of heat resistant material shrink-fit into the fan case of FIG. 10 of an embodiment of the present description. Referring back to FIG. 11, the heat resistant ring 1112 is shown to be shrinkage fit onto the inner diameter of the fan case 1002 in the heat resistant ring notch 1012. In this example, the heat resistant ring 1112 is made of titanium, but heat resistant properties to maintain the structural integrity required for the fan case 1002, such as steel, steel alloys, or any number of commonly used aerospace superalloys. It may be made of another material having a bonding property of over strength property. The heat resistant ring 1112 may be made of a titanium sheet material that is cut, bent into a cylindrical shape and welded along the seam, and may be formed to match the inner diameter of the heat resistant ring notch 1012. The heat resistant ring 1112 may be forged as described above.

By contracting the interference fit as described above, the fan case 1002 is heated and the fan case 1002 is inflated to cause the heat resistant ring 1112 to slide to a position and to be cooled in that state. The fan case 1002 and the heat resistant ring 1112 are forcibly applied to each other with a shrink fit. Alternatively, the heat resistant ring 1112 may be cooled by liquefied nitrogen, reducing its outer diameter and allowing the heat resistant ring 1112 to slip into the heat resistant ring notch 1012. In addition, a combination of the fan case 1002 and the heat resistant ring 1112 may be used to secure the shrinkage interference fit. The heat resistant ring 1112 of titanium is not structurally weakened by the fan case temperature and functions as a buffer in the aluminum fan case 1002 due to the different expansion rates between the two materials. The heat resistant ring 1112 of titanium is exposed to the internal fan case temperature and a portion of the heat is transferred to the fan case 1002. Titanium provides the required strength, which lacks aluminum at higher temperatures. The containment ring 1102 may be made of superalloy. It is understood that a heat resistant ring, such as heat resistant ring 1112, may not engage 100% of the circumference of the outer surface of fan case 1002 due to various factors, such as incomplete curves. For example, the heat resistant ring 1112 may contact 70% of the circumference of the inner surface of the fan case 1002, but the amount of contact may vary depending on the particular application. Nevertheless, when the fan case 1002 is shrink-fitted to the heat resistant ring 1112, the fan case 1002 applies a compressive force radially along the circumference of the inner circumferential surface of the heat resistant ring notch 1012. To be considered. In some applications, it is also understood that it is appropriate to provide a linear material between the heat resistant ring shrinkage interference fits to the fan case such that the compressive force between the heat resistant ring and the fan case is transmitted through the linear material. In one embodiment, the linear material may be made of a compressible material. In other embodiments it is understood that the linear material may be relatively hard or may have other properties such as improved thermal insulation properties to further protect the fan case.

The first stiffener ring notch 1104 and the second stiffener ring notch 1106 may be made of aluminum, titanium, or steel, for example. Depending on the particular gas turbine jet engine being envisioned, the containment ring and one or more stiffener rings may not necessarily require a heat resistant ring, and the heat resistant ring may not necessarily require a containment ring and one or more stiffener rings. This detailed description provides engine designers with a number of options regarding materials, weight, strength, and heat resistance that can be combined to meet the optimum design for a particular engine's purpose and requirements. For example, the pan case 302 may be made of a relatively low weight, low cost material such as aluminum, and the containment ring 702 may have a relatively higher containment strength (such as superalloy inconel 718) as compared to the material of the pan case. It may be made of a material having. However, since the containment ring 702 is made of substantially less mass than the fan case 302, the material of the containment ring 702 is more expensive or heavier than the material of the fan case 302, and depending on the particular application, the total weight or Achieve savings in cost or both. Similarly, fan case 1002 may be made of a relatively low heat resistant material, such as aluminum, and heat resistant ring 1102 may be made of a material having relatively higher heat resistance properties (such as titanium) as compared to the fan case. . However, the heat resistant ring 1112 is substantially less mass than the pan case 1002 so that the material of the heat resistant ring can be more expensive or heavier than the material of the pan case 1002, and also the total weight depending on the particular application. Or a reduction in cost or both.

As discussed above, FIG. 12 schematically illustrates a containment ring 702 located within a containment ring notch 310 formed within an inner surface of a fan case 302. Referring again to FIG. 13, it is understood that the containment ring 702a may be located within the containment ring notch 310a formed in the outer surface of the fan case 302a as in FIG. 13. In this example, containment ring 702a applies radial compressive force directed towards the axis of rotation formed by centerline 107 as schematically indicated by the arrows in FIG. 13. In one embodiment, the radial compressive force is applied continuously around the entirety of the containment ring 702a without interruption.

As described above, the stiffener rings may be disposed at various positions of the fan case 302. 14 illustrates an example where a pair of stiffener rings 502, 602 are disposed opposite the containment ring 702b. As shown in the cross-sectional diagram of FIG. 15, the stiffener ring 502 and the containment ring 702b are respectively shrink fit by a fan case 302 located between the stiffener ring 502 and the containment ring 702b. These stiffener rings 602 are similarly shrink fit fitted to the fan case 302 located between the stiffener ring 602 and the containment ring 702b, respectively. The stiffener rings 502, 602 provide additional containment strength to supplement the containment ring 702b in this embodiment in addition to their reinforcing function.

Again, the pan case 302 may be made of a relatively low weight and relatively inexpensive material, such as aluminum, and the stiffener rings 502 and 602 may be (superalloy inconel 718 or other superalloys, steel, Material with a relatively higher containment or reinforcement strength, such as titanium or other suitable material. However, since the stiffener rings 502, 602 can be made of substantially less mass than the fan case 302, the material of the stiffener rings 502, 602 is more expensive or heavier than the material of the fan case 302. It is also possible to achieve savings in total weight or cost or both, depending on the particular application.

As schematically shown in FIG. 16, a section of the fan case 302 spanning the width of the containment ring 702 may be a portion of the fan blade or fan blade, such as the fan blade 104 (FIGS. 1, 16). A fan blade collision containment area 1600 that may collide with the fan case 302 or portions thereof and leave the remaining blade portions. In such embodiments, the fan blade collision containment area 1600 may be determined by empirical rules through appropriate computer modeling and / or laboratory testing of similar or potential trajectories of separate fan blades or fan blade portions. It is understood that in some embodiments the width of the containment ring may exceed the width of the potential impact area.

Inside fan blade impact zone 1600 there is an area 1602 where a fan blade or a portion of a fan blade may first or potentially collide with fan case 302. As shown in FIG. 16, in many engine designs, the width of the first impact zone 1602 is the rear edge 1608 of the fan blade 104 from the line in front of the front edge 1604 of the fan blade 104. Extends to the rear line. The front direction is a direction toward the front of the fan case 302 through which air enters. The rearward direction is the direction in which air is exhausted from the engine to provide trust in the forward direction.

As best shown in the cross-sectional view of FIG. 17 of the fan blade 104, the front edge 1604 is a portion of the fan blade 104 that extends furthest in the forward direction. In contrast, the rear edge 1608 of the fan blade 104 is the portion of the fan blade 204 that extends farthest in the rearward direction. In the illustrated embodiment, the width of the containment ring 702 spans at least the width of the fan blade first impingement region 1602. Thus, the width of the containment ring 702 when installed in the engine extends at least from the line in front of the front edge 1604 of the fan blade 104 to the line behind the rear edge 1608 of the fan blade 104. do. The width of the fan blade impact containment region 1600 and containment ring 702 may extend beyond the boundaries of the first impact region 1602 in either or both directions, beyond the boundaries of the first impact region 1602. Understand that it may be.

In the embodiment shown, containment ring 702 has a thickness T (FIG. 16). The thickness T of the containment ring 702 is sufficient to prevent the containment ring 702 from being penetrated by the separated blade 104 and the blade fragments in the illustrated embodiment. This thickness may be determined by empirical experiments or appropriate computer modeling based on the strength of the material of the containment ring 702 and the intended or observed speed and mass of the blade or blade fragments.

In the above-described embodiments, rings such as rings 702, 702a, 702b, 502, 602, 1112 are each described as being located within an associated notch. It is understood that one or more rings manufactured separately from the fan case 302 may be attached to the fan case to reinforce the fan case without using the associated notch.

In the above-described embodiments, rings such as rings 702, 702a, 702b, 502, 602, 1112 are described as being in shrinkage fit with fan cases 302, 302a, respectively. It is understood that one or more rings manufactured separately from the fan case 302 may be attached to the fan case to reinforce the fan case so that radial compressive force is applied between the ring and the fan case without using a shrinkage interference fit.

Given the present description, those skilled in the art will understand that numerous modifications in widely different embodiments, applications and configurations of the present description will be presented by themselves without departing from the scope of the present description.

Claims (60)

A turbine case having a turbine configured to rotate along an axis of rotation inside the fan case, and a fan blade connected to the turbine and configured to rotate along the axis of rotation inside the fan case and having a front edge and a rear edge, respectively An outer circumferential surface of either the fan blade containment region and the containment ring of the fan case of the gas turbine jet engine having a fan; the other of the fan blade containment region and the containment ring of the fan case of the gas turbine jet engine. Enclosing the inner perimeter of The inner circumference along the width of the fan blade containment region extending toward at least the rear of the rear edge of each fan blade and at least forward of the front edge of each fan blade using the enclosing inner circumferential surface. Applying a radial compressive force to the outer circumferential surface along the length of the circumference of the face. The method of claim 1, And applying the radial compressive force comprises shrinkage-fitting the containment ring to the fan case. The method of claim 1, Applying the radial compressive force includes placing the containment ring inside a notch formed by the fan case and shaped to secure the containment ring against displacement in the longitudinal direction relative to the fan case. Way. The method of claim 1, The radial compressive force is directed towards a center located on the axis of rotation. The method of claim 1, Machining the containment ring notch in the circumferential direction into the inner surface towards the front end of the fan case, wherein the enclosing and applying the containment ring in the containment ring notch through a shrinkage interference fit. Positioning the method. The method of claim 1, Machining the containment ring notch in the circumferential direction toward the outer surface toward the front end of the fan case, wherein the enclosing and applying the containment ring in the containment ring notch through a shrinkage interference fit. Positioning the method. The method of claim 5, Machining the containment ring notch further includes machining the containment ring notch in a first direction into the inner surface of the fan case, wherein a plurality of grooves are formed on the inner surface in the first direction. How it is formed and aligned. The method of claim 7, wherein Prior to machining the containment ring notch, forging one piece of the containment ring, and machining the containment ring notch into a predetermined shape conforming to the containment ring notch. . The method of claim 8, The containment ring is forged from a piece of containment material, the containment material being selected from the group consisting of steel, titanium, nickel-based superalloys. The method of claim 8, Machining the containment ring further comprises machining an outer surface of the containment ring in a second direction, wherein a plurality of grooves are formed and aligned on the outer surface in the second direction, The inner surface of the containment ring and the outer surface of the containment ring are disposed together, the plurality of grooves on the inner surface of the containment ring notch and the plurality of grooves on the outer surface of the containment ring notch to each other. Aligned in a cross-hatched manner, increasing friction between the containment ring notch and the containment ring and reducing the potential for spin rotation of the containment ring within the containment ring notch. The method of claim 8, Spot welding the containment ring to the containment ring notch at one or more locations to prevent spin rotation of the containment ring relative to the containment ring notch. The method of claim 8, Bolting the containment ring to one or more flanges secured to the containment ring notch to prevent the containment ring from spinning with respect to the containment ring notch. The method of claim 8, Machining the containment ring further includes machining the containment ring by reverse taper, wherein a first outer diameter of the containment ring at a first point toward the front end is remote from the front end. Less than a second inner diameter of said containment ring at said point. The method of claim 5, Machining the containment ring further includes machining the containment ring by reverse taper, wherein a first inner diameter of the fan case at a first point of the containment ring is directed from the front end to the front end. Less than a second inner diameter of said fan case at a second point of said containment ring located remotely. The method of claim 5, Placing the containment ring within the containment ring notch, Heating the fan case to increase the inner diameter of the containment ring to a second diameter greater than the outer diameter of the containment ring at ambient temperature, Placing the containment ring within the containment ring notch, and Causing the fan case to cool to the ambient temperature, causing the containment ring notch to be reduced from the second diameter towards the inner diameter and preventing the decrease by the outer diameter of the containment ring at the ambient temperature; Generating a shrinkage fit. The method of claim 5, Placing the containment ring within the containment ring notch, Heating the fan case to cause the inner diameter of the containment ring notch to increase to a second diameter, Cooling the containment ring to reduce the outer diameter of the containment ring to a second diameter, wherein the second diameter of the containment ring is less than the second diameter of the containment ring notch. Steps, Placing the containment ring within the containment ring notch, and Allowing the fan case to cool to ambient temperature such that the containment ring notch is reduced from the second diameter toward the inner diameter, and the containment ring warms up to the ambient temperature such that the containment ring increases toward the outer diameter And generating the shrinkage fit. The method of claim 5, Placing the containment ring within the containment ring notch, Cooling the containment ring to reduce the outside diameter of the containment ring toward a second outside diameter less than the inside diameter of the containment ring notch, Placing the containment ring within the containment ring notch, and Causing the containment ring to warm up to the ambient temperature such that the containment ring increases towards the outer diameter and inhibits the increase by the inner diameter of the containment ring notch at the ambient temperature, thereby generating the shrinkage inhibiting fit The method further comprises the step of. Way. The method of claim 5, Machining one or more stiffener ring notches in the circumferential direction into the surface of the fan case, and Further comprising placing a stiffener ring within said at least one stiffener ring notch, Wherein the stiffener ring prevents the fan case from turning elliptical under load and temperature conditions generated during operation of the gas turbine jet engine. The method of claim 18, The stiffener ring notch is machined into the outer surface of the fan case, Positioning the stiffener ring, Heating the stiffener ring to increase the first inner diameter of the stiffener ring to a second inner diameter that is greater than an outer surface of the at least one stiffener ring notch at ambient temperature, Placing the stiffener ring in the stiffener ring notch, and Causing the stiffener ring to cool to the ambient temperature, causing the stiffener ring to decrease from the second inner diameter towards the first inner diameter and to prevent the decrease by the outer diameter of the one or more stiffener ring notches, Generating a shrinkage fit. The method of claim 1, The fan case is made of a first material having a first containment strength, and the containment ring is made of a second material having a second containment strength higher than the first material. The method of claim 20, Said first material is aluminum and said second material is a nickel-based superalloy. The method of claim 18, The fan case is made of a first material having a first strength, and the stiffener ring is made of a second material having a second strength higher than the first material. The method of claim 22, Said first material is aluminum and said second material is a nickel-based superalloy. The method of claim 1, The containment ring having a thickness sufficient to prevent penetration of the containment ring by a separate blade. A turbine case having a turbine configured to rotate along an axis of rotation inside the fan case, and a fan blade connected to the turbine and configured to rotate along the axis of rotation inside the fan case and having a front edge and a rear edge, respectively An apparatus for use in a gas turbine jet engine having a fan, the apparatus comprising: A fan case having an inner circumferential surface including a fan blade containment area, and An outer circumferential surface, positioned around the fan case within the fan case containment area to seal the fan blade when the fan blade is detached from the fan, and at least in front of at least the front edge of each fan blade And a containment ring extending rearward of at least the rear edge of each fan blade, The fan blade containment region of the fan case is configured to apply radial compressive force to the outer perimeter surface of the containment ring along a length of the perimeter of the fan blade containment region of the inner perimeter surface. Device for. The method of claim 25, The containment ring having a thickness sufficient to prevent penetration of the containment ring by a separate blade. A turbine case having a turbine configured to rotate along an axis of rotation inside the fan case, and a fan blade connected to the turbine and configured to rotate along the axis of rotation inside the fan case and having a front edge and a rear edge, respectively An apparatus for use in a gas turbine jet engine having a fan, the apparatus comprising: A fan case, wherein the fan case has a front end including a fan blade containment area, an outer surface and an inner surface facing the front end of the fan case, the outer surface and the inner surface within the fan blade containment area. And forming a containment ring notch which is machined in a circumferential direction into one of the outer surface and the inner surface of the fan case; A containment ring, comprising: at least a front edge of at least a front edge of each fan blade and at least a rear edge of each fan blade to provide radial compression from one of the fan case and the containment ring to another of the fan case and the containment ring. And a containment ring extending toward the rear of the containment ring and configured to be disposed within the containment ring. The method of claim 27, And the containment ring is configured to be disposed via a shrink fit fitting. The method of claim 28, And the containment ring notch is machined circumferentially into the inner surface of the fan case towards the front end of the fan case. The method of claim 27, The containment ring is forged from a single piece of containment material and machined into a predetermined shape, the material being selected from the group consisting of steel, titanium, nickel-based superalloys. The method of claim 29, The outer diameter of the containment ring is somewhat larger than the inner diameter of the containment ring notch at ambient temperature, the fan case is heated such that the inner diameter of the containment ring notch increases to a second diameter greater than the outer diameter of the containment ring, Enabling a containment ring to be disposed within the containment ring notch such that the shrinkage restraint fit occurs when the fan case is cooled to the ambient temperature. The method of claim 31, wherein The containment ring notch is machined by reverse tapering such that the first inner diameter of the fan case at a first point towards the front end is less than the second inner diameter of the fan case at a second point far from the front end. And the containment ring is machined in a circumferential direction on the outer surface to conform to the reverse taper. The method of claim 29, The outer diameter of the containment ring is somewhat larger than the inner diameter of the containment ring notch at ambient temperature, the fan case is heated such that the inner diameter of the containment ring notch is increased to a second diameter, and the containment ring is outer diameter of the containment ring Cooled to be reduced to this second outer diameter, allowing the containment ring to be disposed within the containment ring notch, wherein the shrinkage inhibiting fit occurs when the fan case is cooled to the ambient temperature and the containment ring warms up And the second diameter of the containment ring is less than the second diameter of the containment ring notch. The method of claim 29, The outer diameter of the containment ring is somewhat larger than the inner diameter of the containment ring notch at ambient temperature, the containment ring is cooled to reduce the outer diameter of the containment ring to a second diameter, and the containment ring is to be disposed within the containment ring notch. And wherein the containment ring warms up to the ambient temperature, the shrinkage interference fit occurs, and wherein the second diameter of the containment ring is less than the inner diameter of the containment ring notch. . The method of claim 29, A plurality of grooves aligned in a first direction on the machined inner surface of the containment ring notch, and Further comprising a plurality of grooves aligned in a second direction on the machined outer surface of the containment ring, The plurality of grooves on the inner surface of the containment ring notch and the plurality of grooves on the outer surface of the containment ring when the inner surface of the containment ring notch and the outer surface of the containment ring fit together to shrink-fit Which are aligned in a cross-hatched manner with respect to each other, increasing friction between the containment ring notch and the containment ring and reducing the potential for spin rotation of the containment ring inside the containment ring notch. Device for use within. The method of claim 27, Further comprising spot welding at one or more locations for welding the containment ring to the containment ring notch to prevent spin rotation of the containment ring with respect to the containment ring notch. . The method of claim 27, And at least one flange secured to the containment ring notch, wherein the containment ring is bolted to the at least one flange to prevent spin rotation of the containment ring about the containment ring notch. Device for use. The method of claim 27, One or more stiffener ring notches machined in a circumferential direction into the surface of the fan case, A stiffener ring disposed within the at least one stiffener ring notch, the stiffener ring disposed through a shrinkage interference fit, the stiffener ring being operated under load and temperature conditions generated during operation of the gas turbine jet engine. Apparatus for use in a gas turbine jet engine that prevents the fan case from deforming to an elliptical shape. The method of claim 38, And the stiffener ring is forged from one piece of aluminum. The method of claim 27, The stiffener ring notch is machined into the outer surface of the fan case, the inner diameter of the stiffener ring is somewhat smaller than the outer diameter of the one or more stiffener ring notches at ambient temperature, and the stiffener ring is the inner diameter of the stiffener ring. Heated to be increased toward a second diameter greater than the outer diameter of the stiffener ring notch, wherein the stiffener ring can be positioned within the one or more stiffener ring notches, the shrinkage inhibiting when the stiffener ring is cooled to the ambient temperature Apparatus for use in a gas turbine jet engine, where a fit occurs. The method of claim 27, The fan case is forged with any one of steel, titanium and aluminum. The method of claim 27, The fan case is made of any one of steel, titanium and aluminum, the apparatus for use in a gas turbine jet engine. The method of claim 27, The fan case is made of composite material. The method of claim 43, The outer diameter of the containment ring is somewhat larger than the inner diameter of the containment ring notch at ambient temperature, and the containment ring is cooled such that the outer diameter of the containment ring is reduced to a second diameter less than the inner diameter of the containment ring notch, The containment ring may be disposed within a containment ring notch, wherein a shrinkage restraint fit occurs when the containment ring warms to the ambient temperature. The method of claim 27, And the fan case is made of a first material having a first containment strength and the containment ring is made of a second material having a second containment strength higher than the first material. The method of claim 45, Wherein the first material is aluminum and the second material is a nickel-based superalloy. The method of claim 38, And the fan case is made of a first material having a first strength and the stiffener ring is made of a second material having a second strength higher than the first material. The method of claim 47, Wherein the first material is aluminum and the second material is a nickel-based superalloy. As a gas turbine jet engine, A fan case having an inner circumferential surface including a fan blade containment area; A turbine case having a turbine configured to rotate along a rotation axis within the fan case; A fan having a plurality of fan blades configured to rotate along an axis of rotation inside said fan case and connected to said turbine, each having a front edge and a rear edge, and Having an outer circumferential surface, positioned around the fan to seal the fan blade when the fan blade is detached from the fan, toward the front edge of each fan blade and toward the rear edge of each fan blade An extending containment ring, And the fan blade containment region of the fan case is configured to apply radial compressive force to the outer circumferential surface of the containment ring along the length of the circumference of the fan blade containment region of the inner circumferential surface. The method of claim 49, And at least one flange secured to the fan case, wherein the containment ring is bolted to the at least one flange to prevent the containment ring from spin-rotating with respect to the fan case. 51. The method of claim 50, One or more stiffener ring notches machined in a circumferential direction into the surface of the fan case, and A stiffener ring disposed within the at least one stiffener ring notch, the stiffener ring disposed through a shrinkage interference fit, the stiffener ring being operated under load and temperature conditions generated during operation of the gas turbine jet engine. A gas turbine jet engine that prevents the fan casing from going elliptical. The method of claim 49, The fan case has an intermediate portion having an inner surface that forms a heat resistant ring notch that is machined in the circumferential direction into the surface of the fan case, wherein the gas turbine jet engine has a radial compression force from the fan case to the heat resistant ring. And a heat resistant ring configured to be disposed within said heat resistant ring notch to provide a. The method of claim 52, wherein And the heat resistant ring is configured to be disposed through a shrinkage interference fit. As a method of retrofitting a gas turbine jet engine, Removing the fan case from the gas turbine jet engine, and Installing a replacement fan case on the gas turbine jet engine, wherein the replacement fan case is disposed within an inner circumferential surface of the replacement fan case via a shrink fit and collides with the replacement fan case. A containment ring configured to seal the block, the containment ring extending forward of at least the front edge of each of the fan blades and rearward of at least the rear edge of each of the fan blades when retained inside the replacement fan case; How to retrofit a gas turbine jet engine. The method of claim 54, Prior to installing the replacement fan case, further comprising placing the containment ring in a circumferential notch of the inner circumferential surface of the replacement fan case via a shrink fit. A method of operating a gas turbine jet engine, Rotating the fan blades of the fan held inside the fan case along the rotation axis to provide air intake and trust, On the outer circumferential surface of either the containment ring and the fan blade containment region of the fan case, using the inner circumferential surface of the containment ring surrounding the outer circumferential surface and the other of the fan blade containment region of the fan case Applying a radial compressive force, said radial compressive force extending along the length of the circumference of said inner circumferential surface and towards at least a front of a front edge of each fan blade and at least a rear of a rear edge of each fan blade Is directed along a width of the fan blade containment region and directed toward a center located on the axis of rotation. The method of claim 56, wherein And applying radial compressive force to an outer circumferential surface of the fan case using an inner circumferential surface of a stiffener ring surrounding the outer circumferential surface of the fan case. The method of claim 56, wherein And applying radial compressive force to the outer circumferential surface of the heat resistant ring using the inner circumferential surface of the fan case surrounding the outer circumferential surface of the heat resistant ring. A turbine case having a turbine configured to rotate along an axis of rotation inside the fan case, and a fan blade connected to the turbine and configured to rotate along the axis of rotation inside the fan case and having a front edge and a rear edge, respectively An apparatus for use in a gas turbine jet engine having a fan, the apparatus comprising: A fan case having a front end portion and an outer surface and an inner surface facing the front end portion, the fan case comprising a first material having a first containment strength and a first heat resistance, wherein the inner surface defines a fan blade containment region and a flashback heatable region. Shaped, with fan case, Located inside the fan case containment area to seal the fan blades when the fan blades are detached from the fan, at the front of at least the front edge of each fan blade and the rear of the at least rear edge of each fan blade And a containment ring made of a second material having an outer circumferential surface and having a second containment strength higher than the first material, wherein the fan blade containment ring region of the fan case is defined by the outer perimeter of the containment ring. A containment ring, configured to apply a radial compressive force to the face, A stiffener ring, the material being disposed on the outer surface of the fan case rearward of the containment ring to provide a radial compressive force from the stiffener ring to the outer surface of the fan case, the material having a higher strength than the first material. Stiffener ring, and A heat resistant ring, configured to be disposed on the inner surface of the fan case inside the back heatable region to provide a radial compressive force from the back heatable region of the fan case to the heat resistant ring; Apparatus for use in a gas turbine jet engine comprising a heat resistant ring made of a third material having a second heat resistance. The method of claim 59, And wherein the first material is aluminum, the second material is a nickel-based superalloy, the material of the stiffener ring is a nickel-based superalloy, and the third material is titanium.

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