阅读说明：本技术 包括可磨耗材料的蜂窝结构 (Honeycomb structure comprising an abradable material ) 是由 K·阿南德 R·R·阿达拉普拉普 E·卡拉 S·S·帕布拉 于 2020-02-13 设计创作，主要内容包括：各种实施方案包括具有可磨耗材料的蜂窝结构,以及将此类蜂窝结构施加到燃气涡轮发动机的钢部件以减少摩擦损伤的方法。具体实施方案包括具有多个巢室的蜂窝结构,该多个巢室中的每个巢室包括包围空隙的巢室壁,以及位于该多个巢室中的每个巢室的空隙内的可磨耗材料,该可磨耗材料包括金属合金和中空颗粒。(Various embodiments include honeycomb structures having abradable materials, and methods of applying such honeycomb structures to steel components of gas turbine engines to reduce friction damage. Particular embodiments include a honeycomb structure having a plurality of cells, each cell of the plurality of cells including a cell wall surrounding a void, and an abradable material located within the void of each cell of the plurality of cells, the abradable material including a metal alloy and hollow particles.)

1. A honeycomb structure, the honeycomb structure comprising:

a plurality of cells, each cell of the plurality of cells comprising a cell wall surrounding a void; and

an abradable material located within the voids of each cell of the plurality of cells, the abradable material comprising at least one metal alloy and a plurality of hollow particles, the at least one metal alloy comprising a braze alloy, and the plurality of hollow particles comprising hollow fly ash particles.

2. The structure of claim 1, wherein the braze alloy is an active nickel-based braze alloy having a braze temperature in a range of 900 ℃ to 1200 ℃, the active nickel-based braze alloy comprising at least one active element selected from titanium (Ti), zirconium (Zr), and hafnium (Hf).

3. The structure of claim 1, wherein the brazing alloy is Ni-Cr_7％-Si_4.5％-Fe_3％-B_3.2％-Ti_0.5-10％The percentages are weight percentages, and the balance is nickel (Ni).

4. The structure of claim 1 wherein the abradable material has a thickness in the range of 120 mils to 200 mils.

5. The structure of claim 1, wherein the metal alloy is non-porous.

6. The structure of claim 1, wherein the cell walls comprise the abradable material.

7. A honeycomb structure, the honeycomb structure comprising:

a plurality of cells, each cell of the plurality of cells comprising a cell wall surrounding a void; and

an abradable material located within the voids of each cell of the plurality of cells, the abradable material comprising at least one metal alloy comprising MCrAlY-NiAl and a plurality of hollow particles_xWherein M is one or more of Fe, Co and Ni, and x is 20% or more, and the plurality of hollow particles comprise at least one selected from the group consisting of zinc oxide, silicon oxide, aluminum oxide, zirconium oxide, cerium oxide and hydroxyapatite。

8. The structure of claim 7, wherein the metal alloy comprises CoNiCrAlY-NiAl_20％。

9. The structure of claim 8, wherein the plurality of hollow particles comprise zinc oxide and the abradable material comprises greater than 22 wt% of the zinc oxide.

10. The structure of claim 7, wherein the abradable material has a thickness in a range of 120 mils to 200 mils.

11. The structure of claim 7, wherein the metal alloy is non-porous.

12. The structure of claim 7, wherein the cell walls comprise the abradable material.

13. A method of reducing tribological damage to at least one steel component of a turbine engine, the method comprising:

applying a metal abradable filled honeycomb structure to the at least one steel component at a location susceptible to rubbing,

the honeycomb structure includes a plurality of cells, each cell of the plurality of cells including cell walls that surround a void,

the metal abradable includes at least one metal alloy and a plurality of hollow particles, and fills the voids of each cell of the plurality of cells.

14. The method of claim 13, further comprising, prior to applying the filled honeycomb structure to the at least one steel component:

filling the voids of each of the plurality of cells with the metal abradable and bonding the metal abradable to the cell walls.

15. The method of claim 13, wherein applying the honeycomb structure to the at least one steel component comprises bonding both the metal abradable of the honeycomb structure and the cell walls to a surface of the at least one steel component.

16. The method of claim 13, wherein the at least one metal alloy comprises a braze alloy and the plurality of hollow particles comprises hollow fly ash particles.

17. The method of claim 16, wherein the brazing alloy is Ni-Cr_7％-Si_4.5％-Fe_3％-B_3.2％-Ti_4.5％The percentages are weight percentages, and the balance is nickel (Ni).

18. The method of claim 13, wherein the at least one metal alloy comprises MCrAlY-NiAl_xWherein M is one or more of Fe, Co and Ni, and x is 20% or more, and the plurality of hollow particles comprise at least one selected from the group consisting of zinc oxide, silicon oxide, aluminum oxide, zirconium oxide, cerium oxide and hydroxyapatite.

19. The method of claim 18, wherein the metal alloy comprises CoNiCrAlY-NiAl_20％And the plurality of hollow particles comprise zinc oxide, the abradable material comprising greater than 22 wt% of the zinc oxide.

20. The method of claim 13, wherein the at least one steel component is a grade 304 stainless steel component or a grade 310 stainless steel component.

Technical Field

The present disclosure relates generally to honeycomb structures and abradable materials, and more particularly to honeycomb structures including abradable materials applied to steel components of gas turbine engines to reduce friction damage.

Background

Conventionally, abradable material is used between moving and stationary components in a rotating electrical machine, such that one of the components cuts or rubs a groove in the abradable material. In gas turbine engines, abradable material is typically placed on a stationary casing (e.g., shroud), and rotating blades cut/rub grooves into the abradable material. This allows for thermal growth and blade creep to be accommodated. However, when shrouds for gas turbine engines comprise stainless steel as the base material, there is a need to address the problem of increased Coefficient of Thermal Expansion (CTE) mismatch between steel shrouds and conventional abradable materials in order to provide an effective abradable system. These conventional abradable systems fail to account for the high temperature, atmospheric flow, and oxidizing environment of the gas turbine engine.

Disclosure of Invention

The invention discloses a honeycomb structure including abradable material and a method of reducing frictional damage to steel components of a turbine engine. In a first aspect of the disclosure, a honeycomb structure comprises: a plurality of cells, each cell of the plurality of cells comprising a cell wall surrounding a void; and an abradable material located within the voids of each cell of the plurality of cells, the abradable material comprising at least one metal alloy and a plurality of hollow particles, the at least one metal alloy comprising a braze alloy, and the plurality of hollow particles comprising fly ash particles.

In a second aspect of the present disclosure, a honeycomb structure includes: a plurality of cells, each cell of the plurality of cells comprising a cell wall surrounding a void; and in the interstices of each of the plurality of cellsAn abradable material comprising at least one metal alloy comprising MCrAlY-NiAl and a plurality of hollow particles_xWherein M is one or more of Fe, Co and Ni, and x is 20% or more, and the plurality of hollow particles comprise at least one selected from the group consisting of zinc oxide, silicon oxide, aluminum oxide, zirconium oxide, cerium oxide and hydroxyapatite.

In a third aspect of the present disclosure, a method of reducing frictional damage to at least one steel component of a turbine engine comprises: applying a metal abradable filled honeycomb structure to the at least one steel component at a location susceptible to rubbing, the honeycomb structure comprising a plurality of cells, each cell of the plurality of cells comprising a cell wall surrounding a void, the metal abradable comprising at least one metal alloy and a plurality of hollow particles, and filling the void of each cell of the plurality of cells.

Drawings

These and other features of the present disclosure will be more readily understood from the following detailed description of the various aspects of the present disclosure taken in conjunction with the accompanying drawings that depict various embodiments of the disclosure, in which:

FIG. 1 is a schematic cross-sectional view of a portion of a gas turbine engine including blades in close proximity to a casing/shroud.

FIG. 2 schematically illustrates blade wear and shroud cutting after rubbing.

Figure 3 shows a honeycomb structure.

It should be noted that the drawings of the present disclosure are not necessarily drawn to scale. The drawings are intended to depict only typical aspects of the disclosure, and therefore should not be considered as limiting the scope of the disclosure. In the drawings, like numbering represents like elements between the drawings.

Detailed Description

The present disclosure relates generally to honeycomb structures and abradable materials, and more particularly to honeycomb structures including abradable materials applied to steel components of gas turbine engines to reduce friction damage. As discussed above, when shrouds for gas turbine engines include stainless steel as the base material, there is a problem of an increased Coefficient of Thermal Expansion (CTE) mismatch between the steel shrouds and conventional abradable materials. As also noted above, these conventional abradable systems fail to account for the high temperature, atmospheric flow, and oxidizing environment of the gas turbine engine, in addition to the CTE mismatch issue.

Various aspects of the present disclosure include a honeycomb structure with abradable material that addresses the CTE mismatch issues associated with conventional stainless steel components and uses low cost materials while still maintaining high temperature capability (> 1620 ° f) even at large gas flow rates (about 1725 lbs/sec). Additional aspects of the present disclosure include methods for reducing and/or preventing oxidation of the honeycomb structure itself. Thus, damage (e.g., friction damage) and oxidation of steel engine components may be reduced by utilizing the honeycomb structure of the present disclosure as compared to conventional methods. In addition, the reduced susceptibility to damage and oxidation contributes to the extended life expectancy of steel engine components utilizing the honeycomb structures of the present disclosure.

Fig. 1 illustrates a cross-section of a gas turbine engine 100 including a blade 110 configured to rotate about a central (or primary) axis, and a stationary casing section 120 (e.g., a shroud) adjacent the blade 110. Without means for accommodating thermal growth and blade creep, one or both of blade wear and shroud cutting may occur-this is schematically illustrated in FIG. 2. The left side view ("before rub") and the horizontal dashed lines shown in FIG. 2 illustrate the clearance between the blades 110 and the shroud 120 before rubbing and blade wear/shroud cutting occurs. The right side view ("after rub") shows the blade wear gap 210 and shroud cutout 220 after rubbing. As shown in FIG. 2, the vane wear gap 210 and the shroud cutout 220 significantly increase the original clearance (indicated by the horizontal dashed line) between the vane 110 and the shroud 120. Such increased clearance may result in undesirable clearances and airflow leakage, which may reduce the overall performance of engine 100 (FIG. 1).

The honeycomb structure may be used for gap control purposes. Conventional honeycomb structures have a plurality of hexagonal cells, which typically include metal cell walls with air gaps (voids) in the middle to prevent excessive frictional heat and/or wear when rubbing/cutting occurs. However, air gaps within each honeycomb cell may generate air turbulence (e.g., rotational vortices), which is a source of aerodynamic losses. Accordingly, filling honeycomb cells with an abradable material may be beneficial because it may eliminate such aerodynamic losses while the honeycomb cell walls may provide structural integrity. Various aspects of honeycomb filled with abradable material are discussed below with reference to fig. 3.

In aspects of the present disclosure, as shown in fig. 3, a honeycomb structure 300 is provided that includes a plurality of cells 320. Each cell 320 has cell walls 330 that surround voids 310. Each cell 320 includes a cell size (sometimes referred to as a height) "h". Cell size/height h may include dimensions such as, but not limited to: 1/8 ', 3/16', 1/4 'and 3/8' (3.175, 4.7625, 6.35 and 9.525, respectively, in millimeters). In various aspects, cell walls 330 are metallic and may comprise a metal alloy, such as a nickel-based alloy. However, in various aspects, to improve oxidation resistance and/or prevention when compared to conventional methods, cell walls 330 may be provided with an aluminum coating.

According to various aspects, to reduce or prevent aerodynamic losses, voids 310 in cells 320 are filled with an abradable material. The abradable material may include at least one metal alloy and a plurality of hollow particles. The metal alloy of the abradable material may comprise any two or more of the following metals: iron (Fe), nickel (Ni), aluminum (Al), chromium (Cr), titanium (Ti), yttrium (Y), and cobalt (Co). Non-limiting examples of such metal alloys include brazing alloys or MCrAlY-NiAl_xWherein M is one or more of Fe, Co and Ni, and wherein x is 20% or more. The hollow particles of the abradable material may include hollow fly ash particles and hollow ceramic particles. The hollow ceramic particles may include, but are not limited to, hollow spheres of zinc oxide, silicon oxide, aluminum oxide, zirconium oxide, cerium oxide, and hydroxyapatite.

Is mainly composed of Al₂O₃And SiO₂Such particles have the benefit of being low cost fillers for the resulting hollow fly ash particles. Accordingly, one aspect of the present disclosure includes filling voids 31 of cells 320 with an abradable material0, the abradable material comprises hollow fly ash particles held together by an active braze alloy. Active braze alloys containing active elements such as, for example, titanium (Ti), zirconium (Zr), or hafnium (Hf) can wet and bond with metal surfaces such as cell walls 330 of cells 320 even if those cell walls contain oxides such as aluminum oxide, chromium oxide, and silicon oxide. The braze alloy may be, for example, a high temperature nickel-based active braze alloy. Non-limiting examples of Ni-based braze alloys are Ni-7Cr-4.5Si-3Fe-3.2B- (0.5-10) Ti, or more specifically Ni-7Cr-4.5Si-3Fe-3.2B-4.5Ti, where the numbers represent weight% and the balance is nickel (Ni). Such Ni-based braze alloys can bond metals to abradable particles, such as hollow particles (including ceramic particles), due to reaction of the active elements with the particles (e.g., ceramic particles). In addition, the brazing alloy may contain boron (B). When boron (B) is present in the braze alloy, it can react with and bond with, for example, the silica ceramic to form various borosilicate glass phases, thereby improving the adhesion between the braze and the ceramic particles. The composition of the brazing alloy may be selected such that the brazing temperature of the selected brazing alloy is in the range of 900 ℃ to 1200 ℃.

In an exemplary embodiment, preparing an abradable material comprising hollow fly ash particles and a braze alloy, and then filling the honeycomb structure is disclosed below. The braze alloy can be mixed (e.g., centrifugally mixed) with the hollow fly ash particles, and an organic binder (e.g., a specialty grade organic binder) can be added to the mixture. The organic binder may be selected to decompose below the brazing temperature, leaving no residue and allowing for a clean brazed joint. To ensure proper brazing (discussed below), the brazing alloy used in the mixture is preferably in powder form so as to be in full contact with the hollow fly ash particles. Since the optimum mixing volume ratio can be selected based on particle size, 325 mesh (<45 micron particle size) can be used for brazing powders. The resulting mixture may be in the form of a paste, which may then be filled into the voids 310 of the honeycomb structure 300, with the cell walls 330 comprising the mixture (fig. 3). As described above, the cell walls 330 of the honeycomb 300 may be provided with an aluminum coating prior to filling.

In various aspects, after filling, the filled honeycomb structure is heat treated. The heat treatment may be performed in two steps, one step for burning off the organic binder and the other step for melting the braze alloy such that the braze alloy bonds to the cell walls of the honeycomb structure and to the particles of abradable material. Such thermal treatment produces a resulting abradable material that is placed in the cells of the honeycomb and has a selected thickness that may range, for example, from 120 mils to 200 mils (1 mil ═ 1/1000 inches). The resulting abradable material has abradability due to the nature of the material used therein and the porosity entrained therein. The porosity is caused by the hollow particles, thus eliminating the need to add pore formers to the metal alloy of the abradable material, and also allowing the use of non-porous metal alloys.

In another exemplary embodiment of the filled honeycomb structure, the metal alloy may be MCrAlY (where M is Fe, Ni, and/or Co), where NiAl_x(x.gtoreq.20%) is added to the metal alloy as a brittle phase, and the hollow particles may be hollow spheres of zinc oxide. In this embodiment, the zinc oxide comprises greater than 22% by weight of the total abradable material and helps to improve the abradability of the resulting honeycomb structure. The zinc oxide hollow spheres may comprise about 40% by weight of the abradable material. As previously described, the cell walls 330 of the honeycomb 300 may be provided with an aluminum coating prior to filling with the abradable material. Similar to the previously described embodiments, the resulting abradable material disposed in the cells of the honeycomb structure may have a selected thickness, which may range, for example, from 120 mils to 200 mils.

In yet another embodiment of the present disclosure, there is a honeycomb structure comprising a plurality of cells, wherein each cell comprises a cell wall surrounding a void, and wherein the cell wall comprises any of the abradable materials described above. In other words, the abradable material is patterned to form the cell walls of the cells of the honeycomb itself, which still has voids therein or which has voids therein filled with the abradable material.

The above-described honeycomb structure of the present disclosure, including the noted abradable material, not only addresses the conventional CTE mismatch problem between, for example, a steel shroud and the abradable material, but also allows the use of low cost materials (e.g., hollow fly ash particles) while still maintaining high temperature capabilities (e.g., ≧ 1620F.) at atmospheric flows (e.g., 1725 lbs/sec). Additionally, when considered relative to conventional structures, redox and/or prevention of the honeycomb structure itself (e.g., if aluminized) may be provided. All of these features of the honeycomb of the present disclosure contribute to the extended life expectancy of engine components using such honeycombs as compared to conventional methods and resulting structures.

Additional aspects of the present disclosure include methods of reducing frictional damage to at least one steel component of a turbine engine, including stainless steel components, such as grade 304 stainless steel and grade 310 stainless steel. Such methods may include applying a metallic abradable filled honeycomb structure, such as described above, to the steel component at a location susceptible to rubbing. The application of the filled honeycomb structure may include bonding the metal abradable to the surface of the steel component. Bonding the metal abradable to the cell walls of the honeycomb structure may occur prior to or simultaneously with bonding the metal abradable to the surface of the steel component. The filling of the honeycomb and the bonding of the metal abradable may be performed as follows.

As noted above, honeycomb structures contain a plurality of cells that are generally regularly spaced from one another and are generally hexagons having a specified cell size (sometimes referred to as height "h" -see fig. 3). The plurality of cells also typically have a specified cell wall thickness and a specified depth (sometimes referred to as honeycomb thickness). Thus, the volume occupied by a given cell can be easily estimated. Thus, the volume required to fill each cell of the honeycomb and the predetermined amount of overflow can also be easily determined. Such volumes are known and manual or automatic systems in which a predetermined amount of slurry of abradable material is fed into an injector may be used to dispense the slurry into the cells of the honeycomb. The viscosity of the slurry may be adjusted by taking into account the volume and/or weight of the individual components of the abradable material. In one embodiment using an automated system, the system can be programmed to control the amount of slurry dispensed into each individual honeycomb cell, and can be additionally programmed to move from one cell to the next to ensure that the cells are filled to a predetermined volume.

Where the abradable material comprises a metal brazing alloy, a minimum of 8 to 12 volume percent of the metal brazing alloy may be used to ensure continuous contact between the metal brazing particles so as to provide a continuous network of resulting brazed joints. Depending on the wettability of the braze alloy to the ceramic media (e.g., hollow fly ash particles), and also in view of the desired final properties of the abradable, the volume percent of the metallic braze alloy can be increased up to about 75 volume percent. After filling the honeycomb structure, can have a thickness of at least 10^-3The entire filled honeycomb was brazed in a vacuum furnace under a millibar vacuum. After brazing, the brazed structure can be flattened, so that the filled honeycomb structure cells are flush with the honeycomb structure cell wall height. The brazed structure may be subjected to additional heat treatment cycles prior to incorporation into, for example, a steel component of a turbine engine, if desired.

The methods of the present disclosure for reducing tribological damage may reduce tribological damage to components of turbine engines, including stainless steel components, while maintaining high temperature capabilities (e.g., ≧ 1620F.) even at atmospheric flows (e.g., 1725 lbs/sec), when compared to conventional methods, and in some cases utilize low cost materials (e.g., hollow fly ash particles) in accomplishing the same. Thus, the methods of the present disclosure allow for an extended life expectancy of the components when compared to conventional methods, which in turn may reduce overall costs associated with the gas turbine engine, such as manufacturing costs, operating costs, and repair costs.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms (such as "about", "about" and "substantially") is not to be limited to the precise value specified. In at least some cases, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. "about" as applied to a particular value of a range applies to both values, which may indicate +/-10% of the value unless otherwise dependent on the accuracy of the instrument measuring the value. "substantially" in most cases refers primarily to a completely specified or any slight deviation that provides the same technical benefit of the present disclosure.

The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.