Fire retardant engine casing apparatus

1. An engine casing comprising:

an inner shell circumferentially surrounding blades of a fan, a compressor, or a turbine;

an outer shell positioned around the inner shell;

a fire retardant material between the inner shell and the outer shell; and

an internal structure coupled to the inner shell and the outer shell, wherein a volumetric ratio of the internal structure and the fire retardant material between the inner shell and the outer shell is based on at least one of an area of implementation within an axial flow engine or a size of the axial flow engine.

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. The engine casing of claim 1 , wherein at least one of the blades, the inner shell, or the outer shell include titanium.

4. The engine casing of claim 1 , wherein the fire retardant material is a coating on at least one of an outer radial surface of the inner shell, an inner radial surface of the outer shell, or the internal structure coupled to the inner shell and the outer shell.

5. The engine casing of claim 1 , wherein the fire retardant material includes at least one of a composite metal foam, a porous casting, a gel, a powder, an epoxy resin, a ceramic nanostructure, layered double hydroxide based nanocomposites, or ultra-high-temperature ceramics.

6. The engine casing of claim 1 , wherein the outer shell is coated via cold spraying, thermal spraying, or electrochemical deposition.

7. The engine casing of claim 1 , wherein the fire retardant material is formed via at least one of sintering, additive manufacturing, or casting.

8. The engine casing of claim 1 , wherein the inner shell circumferentially surrounds at least a portion of a combustor of the axial flow engine.

9. The axial flow engine of claim 7 , wherein the fire retardant filler material includes an epoxy resin or a ceramic nanostructure.

10. An apparatus comprising:

means for producing aerodynamic forces;

a casing positioned around the means for producing aerodynamic forces, the casing including a cavity between an inner radial surface of the casing and an outer radial surface of the casing;

means for retarding fire inside the cavity; and

means for providing structural support coupled to the inner radial surface and the outer radial surface, wherein a volumetric ratio of the means for providing structural support and the means for retarding fire within the cavity is based on at least one of an area of implementation of the casing in an axial flow engine or a size of the axial flow engine.

11. The apparatus of claim 10 , wherein the means for providing structural support at least partially surrounds the means for retarding fire within the cavity.

12. The engine casing of claim 1 , wherein the internal structure is at least one of a lattice structure or a metal sponge, and wherein the fire retardant material enmeshes with at least one of the lattice structure or the metal sponge.

13. The axial flow engine of claim 1 , wherein the inner shell includes perforations, further including a screen between the inner shell and the fire retardant material.

14. The engine casing of claim 1 , wherein the volumetric ratio of the internal structure and the fire retardant material is defined by each of the internal structure and the fire retardant material occupying between 10% and 90% of a volume between the inner shell and the outer shell.

15. The engine casing of claim 1 , wherein the volumetric ratio includes the internal structure occupying between 60% and 80% of a volume between the inner shell the outer shell, and wherein the volumetric ratio includes the fire retardant material occupying between 20% and 40% of the volume between the inner shell and the outer shell.

16. The engine casing of claim 1 , wherein the volumetric ratio includes a first volume percentage of the fire retardant material when the blades are of the fan or the compressor, and wherein the volumetric ratio includes a second volume percentage of the fire retardant material when the blades are of the turbine, and wherein the second volume percentage is greater than the first volume percentage.

17. An engine casing comprising:

an inner shell circumferentially surrounding blades of a fan, a compressor, or a turbine;

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 defines between 20-50% of a volume between the inner shell and the outer shell; and

at least one of a lattice structure or a metal sponge coupled to an inner radial surface of the outer shell and an outer radial surface of the inner shell, the fire retardant material to entangle with at least one of the lattice structure or the metal sponge, wherein the at least one of the lattice structure or the metal sponge defines between 40-80% of the volume between the inner shell and the outer shell.

18. The engine casing of claim 17 , wherein the inner shell and the outer shell are in contact with a first sidewall and a second sidewall, wherein a cross-sectional area is defined between the inner shell and the outer shell extending from the first sidewall to the second sidewall, and wherein the fire retardant material entangled with at least one of the lattice structure or the metal sponge includes at least a portion of the fire retardant material and at least a portion of the at least one of the lattice structure or the metal sponge occupying a same portion of the cross-sectional area.

19. The engine casing of claim 17 , wherein the inner shell includes a first surface and a second surface opposite the first surface, wherein the fire retardant material is in contact with the first surface, further including an abradable layer fixed to the second surface.