Patent Application
20220411076
The embodiments herein relate to heating systems and more specifically to an aircraft feature with a heating system formed of laser-induced graphene.
Control surfaces of an aircraft may utilize heating to avoid icing. In addition, an aircraft may have internal components that engage fluids, such as tubes, valves and tanks, e.g., utilized for potable or wastewater systems. Such internal components may also utilize heating for aircraft systems to operate properly. Other internal features, such as walkways and seating, may also utilize heating to provide comfort to crew and passengers.
Disclosed is a first method of providing a heating system to an outer skin of an aircraft, including: forming laser-induced graphene (LIG) on a polymer sheet by directing laser energy towards the polymer sheet; coupling electrical leads to the LIG; and bonding the polymer sheet against the outer skin or erosion protection layer secured to the outer skin so that to the polymer sheet conforms with a shape of the outer skin.
In addition to one or more aspects of the disclosed first method, or as an alternate, the first method includes coupling the electrical leads to a power source; and engaging the power source for one or more of: deicing the outer skin of the aircraft; and preventing ice from forming on the outer skin of the aircraft.
In addition to one or more aspects of the disclosed first method, or as an alternate, the outer skin is shaped as an airfoil, and the outer skin is formed of a carbon-glass fiber composite.
In addition to one or more aspects of the disclosed first method, or as an alternate, the first method includes bonding an insulating layer to the polymer sheet.
In addition to one or more aspects of the disclosed first method, or as an alternate the polymer sheet is thermoformed to the shape of the outer skin; and forming the LIG is performed after the polymer sheet is thermoformed to the shape of the outer skin.
In addition to one or more aspects of the disclosed first method, or as an alternate, the LIG is formed in a mesh pattern or a serpentine pattern.
In addition to one or more aspects of the disclosed first method, or as an alternate, the electrical leads are electrically coupled to the LIG via a busbar or a trace.
In addition to one or more aspects of the disclosed first method, or as an alternate, the busbars or traces form an interdigitated pattern.
In addition to one or more aspects of the disclosed first method, or as an alternate the insulating layer is a one or more of a fiberglass composite, a polyimide or silicone insulation; and the polymer sheet is: a thermoset polymer sheet that is formed of phenolics, polyimide (PI), cured epoxy, uncured epoxy, cured cyanate ester, uncured cyanate ester, cured polyurethane, uncured polyurethane, cured silicone, uncured silicone or polyarylacetylene (PAA); or a thermoplastic polymer sheet formed of one or more of polyimide (PI), polyetherketoneketone (PEKK), polyaryletherkeone (PAEK), polyester, polyetheretherketone (PEEK), polyamide, polysulfone, polyetherimide, thermoplastic polyurethane (TPU), or polyethylene naphthalate (PEN).
Further disclosed is a second method of providing a heating system to an interior structure of an aircraft, including forming laser-induced graphene (LIG) on a polymer sheet by directing laser energy towards the polymer sheet; coupling electrical leads to the LIG; bonding the polymer sheet against the interior structure; bonding a carbon fiber composite structure to the polymer sheet; and bonding an insulating layer to the carbon fiber composite structure.
In addition to one or more aspects of the disclosed second method, or as an alternate, the interior structure is: a floor panel formed of titanium or stainless steel; or a seat.
In addition to one or more aspects of the disclosed second method, or as an alternate, the carbon fiber composite structure is formed of: a first carbon fiber composite ply; a support core bonded to the first carbon fiber composite ply; and a second carbon fiber composite ply bonded to the support core.
In addition to one or more aspects of the disclosed second method, or as an alternate, the support core is an aromatic polyamide sheet or an aluminum honeycomb sheet.
In addition to one or more aspects of the disclosed second method, or as an alternate, forming the LIG is performed after bonding the polymer sheet against the interior structure.
In addition to one or more aspects of the disclosed second method, or as an alternate, the LIG is formed as a mesh pattern or a serpentine pattern.
In addition to one or more aspects of the disclosed second method, or as an alternate, the electrical leads are electrically coupled to the LIG via a busbar or a trace.
In addition to one or more aspects of the disclosed second method, or as an alternate, the busbars or traces form an interdigitated pattern.
In addition to one or more aspects of the disclosed second method, or as an alternate the insulating layer is foam; and the polymer sheet is: a thermoset polymer sheet that is formed of phenolics, polyimide (PI), cured epoxy, uncured epoxy, cured cyanate ester, uncured cyanate ester, cured polyurethane, uncured polyurethane, cured silicone, uncured silicone or polyarylacetylene (PAA); or a thermoplastic polymer sheet formed of one or more of polyimide (PI), polyetherketoneketone (PEKK), polyaryletherkeone (PAEK), polyester, polyetheretherketone (PEEK), polyamide, polysulfone, polyetherimide, thermoplastic polyurethane (TPU), or polyethylene naphthalate (PEN).
Further disclosed is a third method of providing a heating system to a component of an aircraft system, including forming laser-induced graphene (LIG) onto an outer skin of the component by directing laser energy towards the skin of the component, wherein the outer skin is formed of a polymer; and coupling electrical leads to the LIG, wherein the component is a valve or tank.
In addition to one or more aspects of the disclosed third method, or as an alternate, the LIG is formed as a mesh pattern or a serpentine pattern.
In addition to one or more aspects of the disclosed third method, or as an alternate, the third method includes bonding an insulating layer to the outer skin, wherein the insulating layer is a one or more of a polyimide or silicone insulation.
In addition to one or more aspects of the disclosed third method, or as an alternate, covering the insulating layer in a fabric covering. In addition to one or more aspects of the disclosed third method, or as an alternate, the electrical leads are electrically coupled to the LIG via a busbar or a trace.
In addition to one or more aspects of the disclosed third method, or as an alternate, the busbars or traces form an interdigitated pattern.
A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.
As indicated, the control surfaces 40 may utilize heating to avoid icing. In addition, the aircraft 10 may have internal components, generally referred to as 50, such as tubes 50A, valves 50B and tanks 50C that engage fluids and may also utilize heating for the aircraft systems to operate properly. Other internal features, generally referred to as 60, such as walkways 60A and seating 60B, may also utilize heating to provide comfort to crew and passengers.
With continued reference to
The polymer sheet 130A may be a thermoset polymer sheet that is formed of phenolics, polyimide (PI), cured epoxy, uncured epoxy, cured cyanate ester, uncured cyanate ester, cured polyurethane, uncured polyurethane, cured silicone, uncured silicone or polyarylacetylene (PAA). Alternatively, the polymer sheet 130A may be a thermoplastic polymer sheet formed of one or more of polyimide (PI), polyetherketoneketone (PEKK), polyaryletherkeone (PAEK), polyester, polyetheretherketone (PEEK), polyamide, polysulfone, polyetherimide, thermoplastic polyurethane (TPU), or polyethylene naphthalate (PEN). In addition, the polymer sheet 130A may be formed of a non-woven, woven or unidirectional polymer.
As shown in block 220, the method includes coupling electrical leads 140A to the LIG 120A. The electrical leads 140A may be connected to a power source 150A operated by a controller 160A located in the aircraft 10. The electrical leads 140A are electrically coupled to the LIG 120A via connectors 170A that can take the form of busbars or traces. The busbars or traces may form an interdigitated pattern, e.g., if the LIG 120A is too resistive. Examples of such patterns are disclosed in US20180213606, titled Carbon allotrope heaters with multiple interdigitated electrodes, and filed on behalf of Goodrich Corp, the disclosure of which his incorporated herein by reference.
The connectors 170A may be secured to, or formed onto, the polymer sheet 130A using known methods. The combination of the polymer sheet 130A, the LIG 120A, and any connectors 170A that enable connecting with electrical leads 140A, collectively may be considered a heater, and the LIG 120A may be considered a heating element.
As shown in block 230, the method includes bonding the polymer sheet 130A against the outer skin 110A or erosion protection layer if such is against the outer skin 110A, so that to the polymer sheet 130A conforms with a shape of the outer skin 110A. The bonding may be accomplished with a first layer of adhesive 180A1, which may be a known suitable adhesive. In some embodiments, depending on the fitting requirements, this process may include block 235 of thermoforming the sheet 130A to the shape of the outer skin 110A. As can be appreciated, bonding and thermoforming may occur simultaneously.
As shown in block 240, the method may further include bonding an insulating layer 190A to the polymer sheet 130A, e.g., to cover the LIG 120A. The bonding may be accomplished with a second layer of adhesive 180A2, which may be a known suitable adhesive and which may be the same as or different than the other layers of adhesive disclosed herein. The insulating layer 190 would ensure that heat radiating from the LIG 120A is directed toward the outer skin 110A. The insulating layer 190A may be one or more of a fiberglass composite, a polyimide or silicone insulation. Not all applications require the insulating layer. For example, ice protection for propellers may be installed on the outside of the propeller, and in such implementation, no insulation may be utilized.
In one embodiment, forming the LIG 120A is performed after the polymer sheet 130A is bonded and/or thermoformed against the outer skin 110A of the aircraft 10. Such an in-situ process may reduce the likelihood of compromising the LIG 120A when manipulating the polymer sheet 130A to the shape of the outer skin 110A. In addition, such an in-situ process may enable a design the pattern of the LIG 120A around a complex geometry that may be difficult to model in advance of bonding and/or thermoforming.
With the above embodiment, the amount of induced graphene may correlate to a resistance of the composite surface layer of the outer skin 110A. That is, the LIG 120A may be formed to directly create (or tune) a resistance of the composite surface of the skin 110A before bonding of the erosion protection layer 185A. Resin chemistry of the skin 110A, fiber volume per polymer sheet 130A, i.e., a fiber fraction of, e.g., 20 to 65 percent, and the process of forming the LIG 120A, may be optimized to meet such resistance requirements.
With continued reference to
The polymer sheet 130B may be a thermoset polymer sheet that is formed of phenolics, polyimide (PI), cured epoxy, uncured epoxy, cured cyanate ester, uncured cyanate ester, cured polyurethane, uncured polyurethane, cured silicone, uncured silicone or polyarylacetylene (PAA). Alternatively, the polymer sheet 130B may be a thermoplastic polymer sheet formed of one or more of polyimide (PI), polyetherketoneketone (PEKK), polyaryletherkeone (PAEK), polyester, polyetheretherketone (PEEK), polyamide, polysulfone, polyetherimide, thermoplastic polyurethane (TPU), or polyethylene naphthalate (PEN). In addition, the polymer sheet 130A may be formed of a non-woven, woven or unidirectional polymer.
As shown in block 420, the method includes coupling electrical leads 140B to the LIG 120B. The electrical leads 140B may be connected to a power source 150B operated by a controller 160B located in the aircraft 10. The electrical leads are electrically coupled to the LIG 120B via connectors 170B that can take the form of busbars or traces. The busbars or traces may form an interdigitated pattern. The connectors 170B may be secured to, or formed onto, the polymer sheet 130B using known methods. The combination of the polymer sheet 130B, the LIG 120B, and any connectors 170B that enable connecting with electrical leads 140B, collectively may be considered a heater, and the LIG 120B may be considered a heating element.
As shown in block 430, the method includes bonding the polymer sheet 130B against a skin 110B of the interior structure 60. The bonding may be accomplished with a first layer of adhesive 180B1, which may be a known suitable adhesive.
As shown in block 440, the method includes bonding a carbon fiber composite structure 200B to the polymer sheet 130B to encase the LIG 120B between the skin 110B of the interior structure 60 and the carbon fiber composite structure 200B. The bonding may be accomplished with a second layer of adhesive 180B2, which may be a known suitable adhesive and which may be the same as or different than the other layers of adhesive disclosed herein.
In one embodiment, the carbon fiber composite structure 200B is formed as a sandwich structure of a first carbon fiber composite ply 210B1, a support core 220B bonded to the first carbon fiber composite ply 210B1, and a second carbon fiber composite ply 210B2 bonded to the support core 220B. The second carbon fiber composite ply 220B2 may be secured to frame rails 230B1, 230B2 of the aircraft 10. In one embodiment, the support core 220B is an aromatic polyamide sheet or an aluminum honeycomb sheet.
As shown in block 450, the method includes bonding an insulating layer 190B to the carbon fiber composite structure 200B. In one embodiment, the insulating layer 190B is foam. The insulating layer 190B is disposed between the frame rails 230B1, 230B2.
In one embodiment, forming the LIG 120B is performed after the polymer sheet 130B is bonded against the skin 110B of the interior structure 60. Such an in-situ process may reduce the likelihood of compromising the LIG 120B when manipulating the polymer sheet 130B during the installation process.
With continued reference to
As non-limiting examples, the LIG 120C is formed as a mesh pattern or a serpentine pattern, for the distribution of heat. Such an in-situ process may enable a designing a pattern of the LIG 120C around a complex geometry that may be difficult to model in advance or otherwise pattern.
As shown in block 620, the method includes coupling electrical leads 140C to the LIG 120C. The electrical leads 140C may be connected to a power source 150C operated by a controller 160C located in the aircraft 10. The electrical leads are electrically coupled to the LIG 120C via connectors 170C that can take the form of busbars or traces. The busbars or traces may form an interdigitated pattern. The connectors 170C may be secured to, or formed onto, the skin 110C of the component 50 using known methods. The combination of the skin 110C, the LIG 120C, and any connectors 170C that enable connecting with electrical leads 140C, collectively may be considered a heater, and the LIG 120C may be considered a heating element.
As shown in block 630, the method may include bonding an insulating layer 190C to the skin 110C of the component 50. The bonding may be accomplished with a layer of adhesive 180C1, which may be a known suitable adhesive that may be the same as or differ from other adhesives disclosed herein. In one embodiment, the insulating layer 190C is a one or more of a polyimide or silicone insulation.
As shown in block 640, the method may include covering the insulating layer 190C with a fabric covering 250C, such as an overbraiding in the case of a tube. That is, optional protection layers or mounting features may be added to the assembly outside the insulation layer. The fabric covering 250C may be secured via a bonding with a second layer of adhesive 180C2, which may be a known suitable adhesive that may be the same as or differ from other adhesives disclosed herein. This will help protect the insulating layer 190C from wear.
As indicated with the above embodiments, a laser can be used to carbonize a layer of an (organic) polymer sheet in a pattern. The carbonized material forms an electrically conductive graphite layer, i.e., laser-induced graphene. Electricity is passed through the graphite layer to heat the organic sheet. The carbonized layer can have a mesh pattern, a serpentine pattern, or any other pattern. The patterns may be scribed directly onto a curved surface such as a tube, valve or tank. The patterns may be lasered on a flat polymer sheet before or after the sheet is wrapped around a curved surface, such as an airfoil. If the carbon is sufficiently adhered to the sheet after carbonization, the sheet may be thermoformed to its final shape after the laser-induced graphene (e.g., the heating element) is carbonized into the surface.
With the disclosed embodiments, detailed heater patterns may be made relatively rapidly and inexpensively fabricated without utilizing relatively hazardous chemicals typically utilized for other processes, such as fabricating heaters with metal foils. Heaters identified herein can be used for ice protection on the exterior of the aircraft or for freeze protection on potable or wastewater systems inside the aircraft. It is to be appreciated that heating element patterns and bus bar and trace configuration and connection areas may also be controlled by the automated laser beam motion.
Thus, the above disclosed in-situ process may provide various benefits, including eliminating separate heater fabrication process steps, and providing tailoring of resistance for local deicing/anti-icing demands. Additional benefits include reducing heater materials and providing a light-weighting and low energy consumption system. Other benefits include providing relatively simple field heater repair due to in-situ processing and providing for reduced process variation and cost. Moreover, the embodiments may provide for minimizing chemical use, resulting in an environmentally friendly solution.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present 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, element components, and/or groups thereof.
Those of skill in the art will appreciate that various example embodiments are shown and described herein, each having certain features in the particular embodiments, but the present disclosure is not thus limited. Rather, the present disclosure can be modified to incorporate any number of variations, alterations, substitutions, combinations, sub-combinations, or equivalent arrangements not heretofore described, but which are commensurate with the scope of the present disclosure. Additionally, while various embodiments of the present disclosure have been described, it is to be understood that aspects of the present disclosure may include only some of the described embodiments. Accordingly, the present disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
