US-12624648-B2 - Fire retardant engine casing apparatus

Abstract

Fire retardant engine casing apparatus are disclosed. An example engine casing includes an inner shell circumferentially surrounding blades of a fan, a compressor, or blades of a turbine, the inner shell including perforations to receive acoustic waves, an outer shell positioned around the inner shell, a fire retardant material between the inner shell and the outer shell, and a screen positioned between an outer radial end of the perforations and the fire retardant material.

Inventors

• Manish Singhal
• Vishnu Das K
• Sagar Pradhan
• Ravindra Shankar Ganiger

Assignees

• GENERAL ELECTRIC COMPANY

Dates

Publication Date

20260512

Application Date

20240229

Priority Date

20211013

Claims (20)

1. 1 . An engine casing comprising: an inner shell circumferentially surrounding blades of a fan, a compressor, or blades of a turbine, the inner shell including perforations to receive acoustic waves; an outer shell positioned around the inner shell; a fire retardant material between the inner shell and the outer shell; and a screen in contact with an outer radial surface of the inner shell and positioned between an outer radial end of the perforations and the fire retardant material.
2. 2 . The engine casing of claim 1 , further including a honeycomb structure fixed to the inner shell and the outer shell, the fire retardant material within cells defined by the honeycomb structure.
3. 3 . The engine casing of claim 1 , wherein the blades include titanium.
4. 4 . The engine casing of claim 1 , wherein at least one of the inner shell or the outer shell includes titanium.
5. 5 . The engine casing of claim 1 , wherein the fire retardant material is at least one of a composite metal foam, a porous casting, a gel, or a powder.
6. 6 . The engine casing of claim 1 , wherein the fire retardant material is a coating on at least one of an inner radial surface of the outer shell or an internal structure fixed to the inner shell and the outer shell.
7. 7 . The engine casing of claim 1 , wherein the fire retardant material includes graphene oxide and layered double hydroxide based nanocomposites.
8. 8 . The engine casing of claim 1 , wherein the fire retardant material includes ceramic nanostructures having graphene oxide layers.
9. 9 . The engine casing of claim 1 , wherein the outer shell is coated via cold spraying, thermal spraying, or electrochemical deposition.
10. 10 . The engine casing of claim 1 , wherein the fire retardant material defines between 60-80% of a volume between the inner shell and the outer shell.
11. 11 . An axial flow engine casing comprising: an inner shell including perforations to receive acoustic waves; an outer shell positioned around the inner shell; a fire retardant material between the inner shell and the outer shell, wherein the fire retardant material is in contact with at least one of an outer radial surface of the inner shell or an inner radial surface of the outer shell; and a screen positioned between the perforations and the fire retardant material.
12. 12 . The axial flow engine casing of claim 11 , further including an internal structure coupled to the inner shell and the outer shell.
13. 13 . The axial flow engine casing of claim 12 , wherein a volumetric ratio of the internal structure and the fire retardant material between the inner shell and the outer shell is based on an area of implementation of the axial flow engine casing in an axial flow engine.
14. 14 . The axial flow engine casing of claim 11 , wherein the fire retardant material includes a layered double hydroxide hybrid nanocomposite.
15. 15 . The axial flow engine casing of claim 11 , wherein the fire retardant material includes ceramic nanostructures having graphene oxide layers.
16. 16 . The axial flow engine casing of claim 11 , wherein the fire retardant material is coupled to an unperforated portion of the inner shell.
17. 17 . The axial flow engine casing of claim 11 , wherein the fire retardant material attenuates the acoustic waves that pass through the perforations.
18. 18 . An apparatus comprising: means for producing aerodynamic forces; means for circumferentially surrounding positioned around the means for producing aerodynamic forces, the means for circumferentially surrounding including a cavity between an inner radial surface of the means for circumferentially surrounding and an outer radial surface of the means for circumferentially surrounding, the inner radial surface including means for receiving acoustic waves; means for retarding fire inside the cavity; and means for screening positioned between the means for retarding fire and the means for receiving acoustic waves to inhibit at least one of (i) the means for retarding fire from flowing through the means for receiving acoustic waves or (ii) the means for retarding from oxidizing from airflow produced by the means for producing aerodynamic forces.
19. 19 . The apparatus of claim 18 , further including means for providing structural support inside the cavity.
20. 20 . The apparatus of claim 19 , wherein the means for retarding fire attenuates the acoustic waves.

Description

RELATED APPLICATION This patent claims the benefit of Indian Provisional Patent Application No. 202111046647, which was filed on Oct. 13, 2021, and U.S. patent application Ser. No. 17/543,347, which was filed Dec. 6, 2021. Indian Provisional Patent Application No. 202111046647 and U.S. patent application Ser. No. 17/543,347 are hereby incorporated herein by reference in their entirety. Priority to Indian Provisional Patent Application No. 202111046647 and U.S. patent application Ser. No. 17/543,347 is hereby claimed. FIELD OF THE DISCLOSURE This disclosure relates generally to turbofan engines and, more particularly, to fire retardant engine casing apparatus. BACKGROUND In recent years, titanium based alloys have been utilized for blades, casings, and/or disks in turbofan engines because of a low density and high strength-to-weight ratio compared to steel. As such, titanium enables greater thrust-to-weight ratios in turbofan engines than other metals. However, despite a higher melting point, most titanium alloys have a lower temperature resistance than steel or nickel alloys, which, accompanied with the ignitability of titanium alloys and the exothermic reaction with oxygen, can result in a titanium fire under certain conditions. Accordingly, steel or nickel alloys are often utilized in hotter areas of the engine. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a schematic cross-sectional view of a prior art example of a turbofan engine. FIG. 2 illustrates an example turbofan engine having at least one fire retardant engine casing apparatus in accordance with the teachings disclosed herein. FIG. 3 illustrates a magnified view of a section of the turbofan engine of FIG. 2. FIG. 4 illustrates a magnified view of the fire retardant engine casing apparatus of the turbofan engine of FIGS. 2 and 3. FIG. 5A illustrates a first example implementation of the fire retardant engine casing apparatus of FIG. 4. FIG. 5B illustrates a second example implementation of the fire retardant engine casing apparatus of FIG. 4. FIG. 5C illustrates a third example implementation of the fire retardant engine casing apparatus of FIG. 4. FIG. 6A illustrates a fourth example implementation of the fire retardant engine casing apparatus of FIG. 4. FIG. 6B illustrates a fifth example implementation of the fire retardant engine casing apparatus of FIG. 4. FIG. 6C illustrates a sixth example implementation of the fire retardant engine casing apparatus of FIG. 4. FIG. 7A illustrates a seventh example implementation of the fire retardant engine casing apparatus of FIG. 4. FIG. 7B illustrates an eighth example implementation of the fire retardant engine casing apparatus of FIG. 4. FIG. 8A illustrates a ninth example implementation of the fire retardant engine casing apparatus of FIG. 4. FIG. 8B illustrates a tenth example implementation of the fire retardant engine casing apparatus of FIG. 4. The figures are not to scale. In general, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. DETAILED DESCRIPTION Although titanium includes favorable characteristics for utilization in turbofan engines, such as a high strength to weight ratio, titanium alloys that are utilized in blades, casings, and/or discs of turbofan engines, are susceptible to fire (e.g., titanium fire). For instance, oxygen and heat, which can result from friction against the titanium surface, can cause titanium to ignite. In some examples, titanium fire can occur as a result of friction between adjacent titanium blades and/or between titanium blades and a surrounding casing as the heat generated from friction can exceed the relative ignition temperature of titanium alloys. In some examples, when a fragment of a titanium blade impinges against a casing, the fragment can burn through and ignite the casing. Accordingly, when turbofan engines include titanium blades and/or casings, more clearance space is incorporated between adjacent blades and/or between blade tips and the casing to reduce friction and, thus, a likelihood of titanium fire occurring. Damages that result from a titanium fire are most severe when the fire breaches an outer layer of the casing causing damage to engine support structures and/or other airframe structures. In some examples, a thicker casing is utilized to prevent the titanium fire from breaching the casing. However, the thicker casing increases the weight of the aircraft, which increases a size and/or quantity of support structures associated with the engine. As such, the increased weight reduces a specific fuel consumption efficiency of the aircraft. Additionally, tight manufacturing tolerances are needed to obtain thrust while preventing too much friction from occurring between the blades and the casing that would otherwise cause ignition. Examples disclosed herein provide fire retardant engine casing apparatus. In certain examples, a casing of an aircraft engin