Ice protection system for truss-reinforced wing of aircraft

Abstract

An anti-icing system (200) for a truss reinforced wing (102) of an aircraft (100) is disclosed. The system (200) comprises: a wing (104); a support bar (106); a joint (110) coupling the support bar (106) to the wing (104) to form a structural truss (108) that trusses the wing (102); the magnetic receptor (110) is arranged on the connector (110) or in the connector (110); and an induction heating coil (202) disposed on or within the truss-reinforced wing (102). The induction heating coil (202) is configured to generate an eddy current inside the magnetic susceptor (110) based on driving with an alternating current (AC) excitation current. Eddy current is circulated through the magnetic susceptor (110), thereby causing Joule heating of the magnetic susceptor (110) to prevent icing on the joint (110).

Description

Technical Field

[0001] The present disclosure relates generally to the field of aircraft, and more particularly to aircraft having truss-braced wings. Background Art

[0002] A truss-reinforced wing is typically a long, thin wing that is structurally reinforced by one or more trusses. The structural support provided by the trusses enables the span of the wing, and accordingly the aspect ratio of the wing, to be increased relative to a conventional cantilever wing. The increased aspect ratio of a truss-reinforced wing reduces lift-induced drag relative to a conventional cantilever wing. In addition, laminar flow is generated when the support braces are attached to the truss-reinforced wing, and this laminar flow provides additional lift to the aircraft. The reduced lift-induced drag and increased lift provided by a truss-reinforced wing relative to a conventional aircraft with a cantilever wing enables aircraft employing truss-reinforced wings to have increased efficiency / reduced fuel consumption in some configurations.

[0003] Truss reinforced wings are subject to ice accumulation during freezing environmental conditions, which is the same as or greater than that of conventional cantilever wings. In particular, ice accumulation may occur at the joints where the rods of the trusses forming the truss reinforced wings are connected to the wing itself. There are several common methods for protecting conventional cantilever wings from ice accumulation. As an example, conductive elements (also known as electric heating pads or blankets) can be integrated into the leading edge surface of the cantilever wing to directly heat the cantilever wing by conduction to prevent ice accumulation on the cantilever wing. Typically, the electric heating pad draws electricity from the aircraft's auxiliary generator. As another example, hot air can be drawn from the aircraft's engine through a series of ducts (e.g., piccolo tubes) that circulate bleed air below the cantilever wing surface to prevent ice accumulation on the cantilever wing.

[0004] However, when applied to the truss reinforced wing of an aircraft, these traditional means for protecting the cantilever wing of an aircraft from ice accumulation may be less efficient or infeasible. Specifically, the extended length of the truss reinforced wing will require a significantly increased number of electric heating pads necessary for the entire length of the truss reinforced wing. In order to prevent ice, the increased number of heating pads will require a certain amount of energy per unit length of the wing, which will increase the power consumption of the aircraft on the entire length of the wing in aggregate, which will reduce the efficiency of the aircraft. In addition, the electric heating pads require fasteners that destroy the smooth surface of the truss reinforced wing and negatively affect the laminar flow formed around the truss reinforced wing. In addition, the slender size of the truss reinforced wing limits the size and throughput of the duct system (the duct system is used to distribute the bleed air across the truss reinforced wing) to the extent that the bleed air will be ineffective for preventing ice accumulation on the truss reinforced wing. In addition, none of these traditional methods specifically solves the problem of ice accumulation on the structural joints of the wing, because the traditional cantilever wing does not have such joints. Summary of the invention

[0005] An anti-icing system for a truss-reinforced wing of an aircraft is disclosed. The system includes: a wing; a support strut; a joint that connects the support strut to the wing to form a structural truss of the truss-reinforced wing; a magnetic susceptor disposed on or in the joint; and an induction heating coil disposed on or in the truss-reinforced wing. The induction heating coil is configured to generate eddy currents in the magnetic susceptor based on driving with an alternating current (AC) excitation current. The eddy currents circulate through the magnetic susceptor, thereby causing Joule heating of the magnetic susceptor to prevent ice accumulation on the joint.

[0006] The features, functions, and advantages that have been discussed can be achieved independently in various embodiments or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 An exemplary embodiment of an aircraft having a truss-stiffened wing is shown.

[0008] Figure 2 Schematically shows the Figure 1 An exemplary embodiment of an anti-icing system 200 for a truss-reinforced wing of an aircraft.

[0009] Figure 3 An exemplary embodiment of an ice protection system for a truss-stiffened wing is schematically illustrated, the ice protection system including magnetic susceptors incorporated into a joint of the truss-stiffened wing.

[0010] Figure 4 Another exemplary embodiment of an ice protection system for a truss-stiffened wing is schematically illustrated and includes a magnetic susceptor incorporated into an aerodynamic fairing of the truss-stiffened wing.

[0011] Figure 5 Another exemplary embodiment of an ice protection system for a truss-stiffened wing is schematically illustrated, the ice protection system including a magnetic susceptor incorporated into the leading edge of the truss-stiffened wing.

[0012] Figures 6 to 8 Exemplary embodiments of different types of induction heating coil arrangements that may be employed in the disclosed truss-stiffened wing anti-icing system are schematically illustrated. DETAILED DESCRIPTION

[0013] When applied to truss reinforced wings, the traditional methods for protecting the cantilever wings of aircraft from ice accumulation may be less efficient or infeasible. As an example, the truss reinforced wing is significantly longer than the traditional cantilever wing, and the extended length of the truss reinforced wing will require a large number of electric heating pads to span the entire length of the truss reinforced wing. A large number of heating pads may increase weight and power consumption (when all heating pads are turned on at the same time), which will reduce the efficiency of the aircraft. In addition, the electric heating pads require fasteners, which destroy the smooth surface of the truss reinforced wing and negatively affect the laminar flow formed by the rods around the truss reinforced wing. As another example, the slender size of the truss reinforced wing may limit the size and throughput of the duct system (the duct system is used to distribute the bleed air across the truss reinforced wing) to the following extent: the volume of the bleed air that can be delivered to the truss reinforced wing will be ineffective for preventing ice accumulation on the truss reinforced wing.

[0014] Accordingly, the present disclosure relates to a method for protecting a truss reinforced wing of an aircraft from ice accretion. Such a method is more effective and efficient than conventional methods for protecting a cantilever wing of an aircraft from ice accretion. In one example, an ice protection system for a truss reinforced wing of an aircraft includes: a wing; a support rod; a joint that connects the support rod to the wing to form a structural truss of the truss reinforced wing; a magnetic susceptor disposed on or in the joint; and an induction heating coil disposed on or in the truss reinforced wing. The induction heating coil is configured to generate eddy currents within a magnet based on being driven using an alternating current (AC) excitation current. The eddy currents circulate through the magnetic susceptor, causing Joule heating of the magnetic susceptor to prevent ice accretion on the joint.

[0015] The use of magnetic susceptors in an ice protection system provides the following technical benefits: the magnetic susceptors can be integrated into the structure of the joints of the truss-stiffened wing so as not to negatively affect the aerodynamic characteristics of the truss-stiffened wing or the laminar flow across the truss-stiffened wing, while the fasteners of traditional electric heating pads will negatively affect the aerodynamic characteristics and / or laminar flow.

[0016] Furthermore, composite structures that are exposed to airflow and direct water impingement paths, such as the leading edge of a wing, are subject to rain erosion. By placing magnetic susceptors on such composite structures, in addition to preventing ice accumulation, the magnetic susceptors provide the additional benefit of preventing rain erosion.

[0017] Furthermore, the magnetic susceptor may be configured such that the Curie temperature of the magnetic susceptor is based at least on the material selection of the truss-stiffened wing, such that the magnetic susceptor may intelligently heat the truss-stiffened wing to the Curie temperature without causing degradation of the material of the truss-stiffened wing due to excessive heating.

[0018] The use of induction heating coils to heat the magnetic susceptors without direct physical contact with the magnetic susceptors provides a technical benefit of having design flexibility to accommodate the slender interior dimensions of a truss-reinforced wing. For example, the induction heating coils can have a low profile (e.g., the thickness of the Litz wire forming the coils can be a lower American Wire Gauge (AWG)) and require only an electrical connection to a controller via a cable that can be flexibly passed through the interior dimensions of the truss-reinforced wing. Such an anti-icing system provides greater design flexibility and reduces weight and cost relative to conventional bleed air systems that require a series of ducts to be arranged inside the wing.

[0019] Figure 1An exemplary embodiment of an aircraft 100 having a truss reinforced wing 102 is shown. The truss reinforced wing 102 includes a wing 104 and a support rod 106, which together form a structural truss 108 that provides additional support and stiffness to the truss reinforced wing 102. In the illustrated embodiment, the support rod 106 is an auxiliary rod. In other embodiments, the support rod can be a different type of rod, such as a lift rod. A joint 110 connects the support rod 106 to the wing 104 to form a structural truss 108. The support rod 106 spans between the joint 110 and the fuselage 112 of the aircraft 100. This design of the truss reinforced wing 102 enables the use of longer and thinner wings. As the wing becomes longer, the aspect ratio of the wing increases and improves the aerodynamic efficiency. A larger aspect ratio generally improves the lift-to-drag ratio, resulting in better fuel efficiency and range. Moreover, as the wing becomes longer, the wing becomes more flexible, causing increased bending and twisting during flight. This flexibility can create structural challenges and may require additional weight to maintain the structural integrity of the wing. The truss-reinforced wing 102 helps overcome these problems by providing a light-weight, high-strength structure that supports a longer wingspan without significantly increasing weight. In particular, the structural trusses 108 help to more efficiently distribute loads without the need for heavy internal reinforcements, and thereby enable the truss-reinforced wing 102 to be constructed using lighter materials.

[0020] Truss reinforced wing 102 is subject to ice accretion during freezing environmental conditions, particularly around joints 110, due to the geometric features of the joints (e.g., corners, edges) and local airflow across joints 110. Therefore, aircraft 100 includes an anti-icing system configured to prevent ice accretion on truss reinforced wing 102. Figures 2 to 3 An exemplary ice protection system 200 is schematically illustrated according to one embodiment of the present disclosure. Figure 2 An underside view of a truss-stiffened wing 102 including an ice protection system 200 is schematically shown. Figure 3 A partial cross-sectional view of a truss-stiffened wing 102 including an ice protection system 200 is schematically shown.

[0021] The anti-icing system 200 includes a magnetic susceptor, which in this embodiment is incorporated into a joint 110 and is referred to herein as a magnetic susceptor joint 110. The magnetic susceptor joint 110 is disposed on the wing 104. The magnetic susceptor joint 110 couples the support rod 106 to the wing 104 to form a structural truss 108 that reinforces the wing 102. The magnetic susceptor joint 110 may couple the support rod 106 to the wing 104 in any suitable manner (e.g., bonding, fasteners).

[0022] Note that in the illustrated embodiment, the size of the magnetic susceptor joint 110 is exaggerated for ease of viewing. In practice, the size of the magnetic susceptor joint 110 may be different. For example, the magnetic susceptor joint may be displaced / integrated downwardly into the body of the wing 104 so that the height of the magnetic susceptor joint 110 is negligible. In some embodiments, the support rod 106 may be directly coupled (e.g., via fasteners, bonding) to the wing 104 to form a joint, and the magnetic susceptor may be integrated into the support rod 106 and / or the wing 104 in the area around the joint.

[0023] The magnetic susceptor fitting 110 includes a ferromagnetic material (eg, an alloy) configured to absorb electromagnetic (EM) energy and convert the EM energy into heat by induction to inhibit ice accumulation on the magnetic susceptor fitting 110 and surrounding areas on the wing 104 .

[0024] In some embodiments, the magnetic susceptor joint 110 includes an alloy selected such that the Curie temperature of the alloy is less than the minimum temperature at which the material of the truss reinforced wing 102 becomes degraded due to excessive heating. Specifically, when the alloy of the magnetic susceptor joint 110 is heated to a temperature greater than the Curie temperature of the alloy, the alloy transitions from ferromagnetic to paramagnetic. When the alloy becomes paramagnetic, the alloy stops absorbing electromagnetic energy, and thus inductive heating of the alloy stops. This phenomenon allows the Curie temperature of the alloy of the magnetic susceptor joint 110 to be used as a temperature set point to control Joule heating to prevent ice accumulation without causing degradation of the truss reinforced wing 102 due to excessive heating. In one example, the truss reinforced wing 102 includes a composite material, and the Curie temperature of the alloy of the magnetic susceptor joint 110 is 160°F or less, which is below the degradation temperature of the composite material. In another example, the truss-stiffened wing 102 includes aluminum and the alloy of the magnetic susceptor joint 110 has a Curie temperature at or below 300° F., which is below the degradation temperature of aluminum.

[0025] In some embodiments, the magnetic susceptor joint 110 is configured such that the magnetic permeability of the magnetic susceptor joint 110 varies throughout the magnetic susceptor joint 110. Figure 3 As shown, the magnetic susceptor joint 110 includes an outer surface portion 300 having a higher magnetic permeability than an inner portion 302. The relatively higher magnetic permeability of the outer surface portion 300 of the magnetic susceptor joint 110 allows more electromagnetic energy to be absorbed by the outer surface portion 300, so that the induction heating is concentrated on the outer surface portion 300 to reach the target area where ice formation is more likely. The relatively lower magnetic permeability of the inner portion 302 of the magnetic susceptor joint 110 causes the inner portion 302 to be heated to a lesser extent, so as to provide a thermal buffer for other materials of the truss reinforced wing 102 near the magnetic susceptor joint 110.

[0026] In the illustrated embodiment, the magnetic susceptor joint 110 is depicted as having an outer surface portion 300 and an inner portion 302 having different degrees of magnetic permeability. It should be understood that the magnetic permeability of the magnetic susceptor joint 110 can vary in any suitable manner. In other embodiments, the magnetic permeability of the magnetic susceptor joint 110 can have a gradient that varies across the thickness of the magnetic susceptor joint 110, for example, so that electromagnetic energy absorption varies according to the thickness of the magnetic susceptor joint 110.

[0027] The magnetic susceptor joint 110 may be manufactured in any suitable manner to achieve a varying magnetic permeability of the magnetic susceptor joint 110. In some embodiments, the magnetic susceptor joint 110 may be additively manufactured to achieve a varying magnetic permeability of the magnetic susceptor joint 110. In other embodiments, the magnetic susceptor joint 110 may be manufactured from a first material having a first magnetic permeability, and then the surface of the magnetic susceptor joint 110 may be coated with a second material having a second magnetic permeability higher than the first magnetic permeability. In some embodiments, the magnetic susceptor joint 110 may be manufactured via a spray coating process that forms multiple layers of different alloys having different magnetic permeabilities.

[0028] In this embodiment, the anti-icing system 200 also includes an induction heating coil 202 disposed within the wing 104. More specifically, the truss reinforced wing 102 includes a composite skin 306 coating the exterior of the wing 104. The induction heating coil 202 is disposed within the truss reinforced wing 102 such that the composite skin 306 is located intermediate the induction heating coil 202 and the magnetic susceptor joint 110. The induction heating coil 202 may have any suitable spacing and / or length to provide sufficient electromagnetic energy to the magnetic susceptor joint 110 to provide Joule heating for the magnetic susceptor joint 110 and / or anti-icing on the wing 104. Because the anti-icing system 200 employs induction heating, the induction heating coil 202 does not have to be in contact with the magnetic susceptor joint 110. This allows for flexibility in being able to place the induction heating coil 202 on or within the wing 104 to accommodate other structures as desired. In some other embodiments, the induction heating coils 202 may be disposed on the surface of the wing 104 or incorporated into the material of the wing 104 .

[0029] In some embodiments, the anti-icing system 200 may include a concentrator 310 positioned adjacent to the induction heating coil 202. The concentrator may be configured to modify the magnetic flux to increase the efficiency of the Joule heating of the induction heating coil 202. In some configurations, the concentrator may be mounted to reflect or focus the magnetic field generated by the induction heating coil 202 toward the magnetic susceptor junction 110. Furthermore, the concentrator may help isolate other components (not shown) from the magnetic field generated by the induction heating coil 202.

[0030] like Figure 2 As shown, the induction heating coil 202 is electrically coupled to a controller 204 via a cable 206. The controller 204 is located within the fuselage 112 of the aircraft 100 (e.g., in a pressurized compartment of the aircraft 100). The controller 204 is configured to serve as a power source for the induction heating coil 202. More specifically, the controller 204 is configured to drive the induction heating coil 202 with a high-frequency alternating current (AC) excitation current (e.g., 100 kHz). The induction heating coil 202 is configured to generate a time-varying EM field based on being driven by the high-frequency AC excitation current.

[0031] like Figure 3 As shown, the time-varying electromagnetic field induces eddy currents 304 that circulate through the magnetic susceptor joint 110, causing Joule heating of the magnetic susceptor joint 110, which inhibits ice 308 from accumulating on the magnetic susceptor joint 110 and surrounding areas on the wing 104. The anti-icing system 200 may be configured to generate any suitable amount of heat to inhibit ice accumulation on the truss reinforced wing 102.

[0032] Depending on the implementation, the controller 204 may have different levels of control intelligence. In some implementations, the controller 204 is configured to drive the magnetic susceptor joint 110 with an AC excitation current of a fixed voltage and a fixed frequency. For example, the anti-icing system 200 may be manually turned on and off via a switch in the cockpit of the aircraft 100, and the controller 204 provides a high frequency AC excitation current to the induction heating coil 202 when the anti-icing system 200 is turned on. In this implementation, the Curie temperature of the magnetic susceptor joint 110 serves as a temperature set point that allows heating to prevent ice accumulation while not overheating the material of the truss reinforced wing 102 to the point of causing degradation.

[0033] In other embodiments, the controller 204 is configured to drive the induction heating coil 202 with a high-frequency AC excitation current. In addition, the controller 204 is configured to sense the impedance of the induction heating coil and adjust the parameters of the high-frequency AC excitation current based on the sensed impedance of the induction heating coil. For example, the controller 204 can adjust the voltage of the high-frequency AC excitation current to achieve a desired level of heating for a particular operating condition of the aircraft, thereby preventing ice accumulation on the truss reinforced wing 102.

[0034] In other embodiments, the ice protection system 200 may include one or more temperature sensors electrically coupled to the controller 204. The one or more temperature sensors are configured to send signals to the controller 204 indicating ambient temperatures at different regions of the truss reinforced wing 102. The controller 204 is configured to adjust parameters of the high frequency AC excitation current based on the signals received from the one or more temperature sensors to achieve a desired level of heating for a particular operating condition of the aircraft, thereby inhibiting ice accumulation on the truss reinforced wing 102.

[0035] The controller 204 may take any suitable form of computer hardware, software, and / or firmware to control the operation of the induction heating coils 202. In some embodiments, the controller 204 is configured to control the operation of multiple induction heating coils dispersed throughout different regions of one or more wings of the aircraft 100. In these embodiments, the controller 204 operates according to a centralized control mechanism. In other embodiments, multiple different controllers may be dispersed throughout the aircraft 100 to control different induction heating coils. In these embodiments, the controllers operate according to a decentralized control mechanism, wherein the controllers correspond one-to-one with the induction heating coils and can act independently of the other controllers.

[0036] In some embodiments, a truss-stiffened wing may include an aerodynamic fairing to enclose the joint coupling the support beam to the wing to improve the aerodynamic properties of the truss-stiffened wing and / or protect the joint from other environmental effects, such as corrosion, foreign objects, and ice formation. Figure 4 An exemplary embodiment of an anti-icing system 400 for a truss reinforced wing 402 is schematically illustrated, the anti-icing system including a magnetic susceptor 404 incorporated into an aerodynamic fairing 406 of the truss reinforced wing 402. The truss reinforced wing 402 includes a wing 408 and a support rod 410 coupled to the wing 408 via a joint 412. Specifically, the support rod 410 is coupled to the joint 412 via a fastener 414. The joint 412 is further coupled to a mounting structure 418 disposed within the wing 408 via a plurality of fasteners 416. The joint 412 and the plurality of fasteners 414, 416 form a geometry that may potentially reduce laminar flow across the truss reinforced wing 402. Therefore, the truss reinforced wing 402 includes an aerodynamic fairing 406 that at least partially covers the joint 412 and the plurality of fasteners 414, 416 to improve aerodynamic characteristics and increase laminar flow across the truss reinforced wing 402. In some embodiments, the aerodynamic fairing 406 encloses a joint 412 and a plurality of fasteners 414 , 416 on a surface of the wing 408 .

[0037] Note that support rod 410 may be coupled to joint 412, and joint 412 may be coupled to wing 402 using any suitable number of fasteners. Alternatively or additionally, support rod 410 may be coupled to joint 412 and joint 412 may be coupled to wing 402.

[0038] The aerodynamic fairing 406 includes a magnetic susceptor 404 disposed on an outer surface of the aerodynamic fairing 406. The magnetic susceptor 404 may be disposed on the surface of the aerodynamic fairing 406 in any suitable manner (eg, spraying, deposition, bonding, additive manufacturing).

[0039] Aerodynamic fairing 406 also includes a composite layer 420 that is coupled (eg, bonded) to a composite skin 422 of wing 408. Composite layer 420 enables aerodynamic fairing 406 to be coupled to wing 408 in a smooth manner to improve aerodynamic properties.

[0040] The induction heating coil 424 is disposed below the aerodynamic fairing 406. For example, the induction heating coil 424 can be coupled to or otherwise incorporated into the composite layer 420. The induction heating coil 424 is electrically coupled to the controller via a cable 426. The controller 204 is configured to drive the induction heating coil 424 using a high frequency AC excitation current. The induction heating coil 424 is configured to generate a time-varying electromagnetic field based on being driven by the high frequency AC excitation current. The time-varying electromagnetic field induces eddy currents, which circulate through the magnetic susceptors 404 on the surface of the aerodynamic fairing 406, causing Joule heating of the magnetic susceptors 404, which prevents ice 428 from accumulating on the aerodynamic fairing 406 and surrounding areas on the wing 408.

[0041] In some embodiments, the induction heating coil 424 may be disposed within the wing 408 rather than beneath the aerodynamic fairing 406. In such embodiments, the induction heating coil 424 may generate an electromagnetic field that is suitably large enough to induce eddy currents that pass through the magnetic susceptors 404 disposed on the surface of the aerodynamic fairing 406.

[0042] Figure 5 An exemplary embodiment of an ice protection system 500 for a truss reinforced wing 502 is schematically illustrated and includes a magnetic susceptor 504 incorporated into a leading edge 506 susceptible to ice accumulation of the truss reinforced wing 502. The ice protection system 500 also includes an anti-corrosion shield 508, an induction heating coil 510, a concentrator 512, and a composite structure 514.

[0043] Corrosion shield 508 is configured to protect one or more components of ice protection system 500 from environmentally induced degradation.

[0044] The magnetic susceptor 504 is positioned adjacent to the erosion shield 508 within the truss reinforced wing 502. The magnetic susceptor 504 is shaped to conform to the shape of the erosion shield 508. The magnetic susceptor 504 includes a ferromagnetic material configured to absorb electromagnetic energy and convert the electromagnetic energy into heat via induction to prevent ice accumulation on the leading edge 506 of the truss reinforced wing 502. In some embodiments, the magnetic susceptor 504 includes an alloy selected such that the Curie temperature of the alloy is less than the minimum temperature at which the material of the truss reinforced wing 502 becomes degraded due to excessive heating. In some embodiments, the magnetic susceptor 504 is configured such that the magnetic permeability of the magnetic susceptor 504 varies throughout the magnetic susceptor 504.

[0045] The induction heating coil 510 is positioned adjacent to the magnetic susceptor 504 within the truss reinforced wing 502. The induction heating coil 510 is shaped to conform to the shape of the magnetic susceptor 504. The induction heating coil 510 is electrically coupled to an AC power source, such as the controller 204. The controller 204 drives the induction heating coil 510 with a high frequency AC excitation current to generate an electromagnetic field in the induction heating coil 510, which induces eddy currents to flow through the magnetic susceptor 504 to cause Joule heating of the magnetic susceptor 504, thereby preventing ice accumulation on the leading edge 506 of the truss reinforced wing 502.

[0046] In some embodiments, the anti-icing system 500 includes a concentrator 512 positioned adjacent to the induction heating coil 510 within the truss reinforced wing 502. The concentrator 512 is shaped to conform to the shape of the induction heating coil 510. The concentrator 512 is configured to change the magnetic flux to increase the efficiency of the Joule heating of the induction heating coil 510. In some configurations, the concentrator 512 can be mounted to reflect or focus the magnetic field generated by the induction heating coil 510 toward the magnetic susceptor 504. Moreover, the concentrator 512 can help isolate other components (not shown) from the magnetic field generated by the induction heating coil 510.

[0047] Composite structure 514 is configured to support various components of anti-icing system 500 on truss-stiffened wing 502. In some embodiments, magnetic susceptor 504 includes an alloy selected to have a Curie temperature based on the material of composite structure 514 so as not to excessively heat composite structure 514 when providing anti-icing functionality via induction heating.

[0048] Magnetic susceptors are described herein as being incorporated into joints, aerodynamic fairings, and / or the leading edge of a truss-reinforced wing. It should be noted that the magnetic susceptors may be incorporated into any suitable structure of a truss-reinforced wing or another portion of an aircraft to provide an anti-icing function via induction heating. As an example, in some embodiments, one or more magnetic susceptors may be disposed on or within a support rod of a truss-reinforced wing to provide an induction heating function to protect the support rod from ice accumulation. Other locations may include, but are not limited to, a plurality of control surfaces, detection and measurement equipment (e.g., airspeed probes), and surfaces close to an engine air inlet.

[0049] In various embodiments, different types of induction heating coil arrangements may be employed in an anti-icing system. Figure 5-Figure 7 Exemplary embodiments of different types of induction heating coil arrangements that may be employed in the disclosed truss-stiffened wing anti-icing system are schematically illustrated.

[0050] Figure 6An exemplary embodiment of an induction heating coil 600 is schematically shown. The induction heating coil 600 has a spiral "pancake" type arrangement that enables the induction heating coil 600 to lie flat and have an approximate thickness corresponding to the diameter of the coil itself. The induction heating coil 600 is electrically coupled to an AC power source 602, such as Figure 2 Controller 204 shown in FIG. 6 . AC power source 602 drives the induction heating coil with a high frequency AC excitation current to generate an electromagnetic field in the induction heating coil 600, which induces eddy currents to flow through adjacent magnetic susceptors to cause Joule heating of the magnetic susceptors, thereby preventing ice accumulation. This arrangement of the induction heating coil 600 generates a cold spot 604 in the central area of ​​the induction heating coil 600.

[0051] Figure 7 Another exemplary embodiment of an induction heating coil 700 is schematically shown. The induction heating coil 700 includes a first coil 702 and a second coil 704. The first coil 702 and the second coil 704 have a spiral "pancake" type arrangement that enables the induction heating coil 700 to lie flat and have an approximate thickness corresponding to the diameter of the coil itself. The first coil 702 and the second coil 704 are electrically connected to an AC power source 706 so that current flows through both the first coil 702 and the second coil 704 in the same direction. The arrows show the relative directions of the current flowing through the first coil 702 and the second coil 704 at a given moment. The AC power source 706 drives the induction heating coil 700 with a high frequency AC excitation current to generate an electromagnetic field in the induction heating coil 700, which induces eddy currents to flow through adjacent magnetic susceptors to cause Joule heating of the magnetic susceptors, thereby preventing ice accumulation. This arrangement of the induction heating coil 700 creates relatively cold spots in the first region 708 and the second region 710 of the induction heating coil 700. These cold spots 708, 710 are relatively Figure 5 Cold spots 504 generated by induction heating coils 500 are shown offset. The specific arrangement of induction heating coils employed in an ice protection system may be selected based at least on the location of one or more cold spots relative to the structure of the truss-stiffened wing in which the induction heating coils of the ice protection system are employed.

[0052] Figure 8Another exemplary embodiment of an induction heating coil 800 is schematically shown. The induction heating coil 800 includes a first coil 802, a second coil 804, and a third coil 806. The first coil 802, the second coil 804, and the third coil 806 have a spiral "pancake" type arrangement that enables the induction heating coil 800 to lie flat and have an approximate thickness corresponding to the diameter of the coil itself. The first coil 802 and the second coil 804 are electrically connected to a first AC power source 808. The third coil 806 is electrically connected to a second AC power source 810. The arrows show the relative directions of the currents flowing through the first coil 802, the second coil 804, and the third coil 806 at a given moment.

[0053] The first AC power source 808 and the second AC power source 810 are connected to the controller 812. The controller 812 is configured to control the first AC power source 808 to drive the first coil 802 and the second coil 804 using a first high-frequency AC excitation current having a first frequency and a first phase, thereby generating an electromagnetic field in the induction heating coil 800, which induces eddy currents to flow through adjacent magnetic susceptors to cause Joule heating of the magnetic susceptors to prevent ice accumulation. The controller 812 is also configured to control the second AC power source 810 to drive the third coil 806 using a second high-frequency AC excitation current having a second frequency and a second phase different from the first frequency and the first phase of the first high-frequency AC excitation current. The offset in frequency and phase between the two high-frequency AC excitation currents causes the average heating of the third coil 806 to be added to the average heating of the first coil 802 and the second coil 804, so that the induction heating coil 800 does not generate any cold spots. If all three coils are driven at the same frequency with a constant phase difference, the cold spots of the coil pairs will not be eliminated, but only moved to different positions. The induction heating coil 800 provides induction heating in the anti-icing system without creating any cold spots, however, relative to Figure 6 The induction heating coil 600 and Figure 7 Compared to the induction heating coil 700 shown in FIG. 8 , the induction heating coil 800 may have increased cost and complexity.

[0054] Figures 6 to 8 The heating coils shown in the drawings may have any suitable spacing and / or length to provide sufficient electromagnetic energy to the magnetic susceptor to provide Joule heating on and around the magnetic susceptor for anti-icing. Such spacing / length of the induction heating coils may depend on where the magnetic susceptor is located on the aircraft (e.g., joint, aerodynamic fairing, leading edge of wing).

[0055] Compared to conventional anti-icing systems for protecting cantilever wings of an aircraft from ice accumulation, the anti-icing system of the present disclosure is more effective and efficient in preventing ice accumulation on the truss reinforced wings of an aircraft (and more specifically, the joints of the truss reinforced wings). Such an anti-icing system employs induction heating via magnetic susceptors. Specifically, eddy currents are induced in the magnetic susceptors, thereby causing Joule heating of the magnetic susceptors to prevent ice accumulation on the joints (and other parts) of the truss reinforced wings. The use of magnetic susceptors in an anti-icing system provides the following technical benefits: the magnetic susceptors can be integrated into the structure of the joints of the truss reinforced wings so as not to negatively affect the aerodynamic properties of the truss reinforced wings or the laminar flow across the truss reinforced wings, while the fasteners of conventional electric heating pads will negatively affect the aerodynamic properties and / or laminar flow.

[0056] Furthermore, the magnetic susceptor may be configured such that a Curie temperature of the magnetic susceptor is selected based at least on the material of the truss-reinforced wing, such that the magnetic susceptor may intelligently heat the truss-reinforced wing to the Curie temperature without causing degradation of the material of the truss-reinforced wing due to excessive heating.

[0057] The use of induction heating coils to heat the magnetic susceptors without direct physical contact with the magnetic susceptors provides a technical benefit of having design flexibility to accommodate the slender interior dimensions of the truss reinforced wing. For example, the induction heating coils can have a low profile (e.g., thickness of the coil) and require only electrical connections to the controller via cables that can be flexibly passed through the interior dimensions of the truss reinforced wing. Such an anti-icing system provides greater design flexibility and reduces weight and cost relative to conventional bleed air systems that require a series of ducts to be arranged inside the wing.

[0058] The anti-icing system of the present disclosure is described herein primarily in the context of protecting the joints of a truss-reinforced wing of an aircraft from ice accumulation. In general, the anti-icing system of the present disclosure may be employed to protect any joint near an aerodynamic surface, or any joint that is subject to ice accumulation where ice may alter the desired aerodynamic flow. Furthermore, the concepts described herein are broadly applicable to protecting other components of a wing other than the joints from ice accumulation. Furthermore, in embodiments where the truss-reinforced wing includes a composite structure, magnetic susceptors may be disposed on such a composite structure to protect the composite structure from both rain erosion and ice accumulation. Furthermore, the concepts described herein are broadly applicable to protecting other components of an aircraft from ice accumulation (or even protecting other types of vehicles in other applications such as space or marine applications from ice accumulation).

[0059] In an example, an anti-icing system for a truss-reinforced wing of an aircraft includes: a wing; a support rod; a joint, connecting the support rod to the wing to form a structural truss of the truss-reinforced wing; a magnetic susceptor, disposed on or in the joint; and an induction heating coil, disposed on or in the truss-reinforced wing, wherein the induction heating coil is configured to generate eddy currents inside the magnetic susceptor based on driving with an alternating current (AC) excitation current, and wherein the eddy currents circulate through the magnetic susceptor, thereby causing Joule heating of the magnetic susceptor to prevent ice accumulation on the joint. In this example and / or other examples, the magnetic susceptor can be incorporated into the joint connecting the support rod to the wing. In this example and / or other examples, the magnetic susceptor can include an alloy having a Curie temperature less than a minimum temperature at which the material of the truss-reinforced wing becomes degraded due to excessive heating. In this example and / or other embodiments, the magnetic permeability of the magnetic susceptor can vary throughout the magnetic susceptor. In this example and / or other examples, the magnetic susceptor can achieve a variable magnetic permeability of the magnetic susceptor by additive manufacturing. In this example and / or other examples, the magnetic permeability of the outer part of the magnetic susceptor can be higher than the magnetic permeability of the inner part of the magnetic susceptor. In this example and / or other examples, the truss reinforced wing can include a composite skin, and the induction heating coil can be arranged in the truss reinforced wing so that the composite skin is located between the induction heating coil and the magnetic susceptor. In this example and / or other examples, the system can also include an aerodynamic fairing that at least partially covers the joint, the magnetic susceptor can be arranged on or in the aerodynamic fairing, and the induction heating coil can be arranged below the aerodynamic fairing. In this example and / or other examples, the system can also include a controller that is electrically connected to the induction heating coil and is configured to drive the induction heating coil using an AC excitation current of a fixed voltage and a fixed frequency. In this example and / or other examples, the system may further include a controller electrically connected to the induction heating coil and configured to 1) drive the induction heating coil with an AC excitation current, 2) sense the impedance of the induction heating coil, and 3) adjust parameters of the AC excitation current based on the sensed impedance of the induction heating coil.

[0060] In another example, an anti-icing system for a truss-reinforced wing of an aircraft includes: a wing; a support rod; a magnetic susceptor joint, connecting the support rod to the wing to form a structural truss of the truss-reinforced wing; an induction heating coil, disposed on or within the truss-reinforced wing; and a controller, electrically connected to the induction heating coil, and configured to drive the induction heating coil with an alternating current (AC) excitation current, sense the impedance of the induction heating coil, and adjust the parameters of the AC excitation current based on the sensed impedance of the induction heating coil, wherein the induction heating coil is configured to generate eddy currents inside the magnetic susceptor based on driving with the AC excitation current, and wherein the eddy currents circulate through the magnetic susceptor joint, thereby causing Joule heating of the magnetic susceptor joint to prevent ice accumulation on the magnetic susceptor joint. In this example and / or other examples, the magnetic susceptor joint may include an alloy having a Curie temperature less than a minimum temperature at which the material of the truss-reinforced wing becomes degraded due to excessive heating. In this example and / or other examples, the magnetic permeability of the magnetic susceptor joint may vary throughout the magnetic susceptor. In this example and / or other examples, the magnetic susceptor joint can be manufactured by additive manufacturing to achieve a variable magnetic permeability of the magnetic susceptor joint. In this example and / or other examples, the magnetic permeability of the outer portion of the magnetic susceptor joint can be higher than the magnetic permeability of the inner portion of the magnetic susceptor joint. In this example and / or other examples, the truss reinforced wing can include a composite skin, and the induction heating coil can be arranged in the truss reinforced wing so that the composite skin is located between the induction heating coil and the magnetic susceptor joint.

[0061] In another example, an anti-icing system for a truss-reinforced wing of an aircraft includes: a wing; a support rod; a joint, connecting the support rod to the wing to form a structural truss of the truss-reinforced wing; a magnetic susceptor, disposed on or in the truss-reinforced wing, wherein the magnetic permeability of the magnetic susceptor varies throughout the magnetic susceptor; and an induction heating coil, disposed on or in the truss-reinforced wing, wherein the induction heating coil is configured to generate eddy currents inside the magnetic susceptor based on driving with an alternating current (AC) excitation current, and wherein the eddy currents circulate through the magnetic susceptor, thereby causing Joule heating of the magnetic susceptor to prevent ice accumulation on the joint. In this example and / or other examples, the magnetic susceptor can be incorporated into the joint connecting the support rod to the wing. In this example and / or other embodiments, the magnetic susceptor can achieve a variable magnetic permeability of the magnetic susceptor by additive manufacturing. In this example and / or other examples, the magnetic permeability of the outer portion of the magnetic susceptor can be higher than the magnetic permeability of the inner portion of the magnetic susceptor.

[0062] The present disclosure includes all novel and non-obvious combinations and sub-combinations of the multiple features and techniques disclosed herein. The multiple features and techniques disclosed herein are not necessarily required for all examples of the present disclosure. In addition, the multiple features and techniques disclosed herein may define patentable subject matter other than the disclosed examples, and may find utility in other implementations not explicitly disclosed herein.

[0063] Parts List:

[0064] Aircraft 100; truss reinforced wing 102; wing 104; strut 106; structural truss 108; magnetic susceptor joint 110; fuselage 112; ice protection system 200; induction heating coil 202; controller 204; cable 206; exterior surface portion 300; interior portion 302; eddy current 304; composite skin 306; ice 308; concentrator 310; ice protection system 400; truss reinforced wing 402; magnetic susceptor 404; aerodynamic fairing 406; wing 408; strut 410; joint 412; fastener 414; fastener 416; mounting structure 418; composite layer 420; composite skin 422; induction heating coil 424; cable 426; ice 428; anti-icing system 500; truss reinforced wing 502; magnetic receptor 504; leading edge 506; anti-corrosion shield 508; induction heating coil 510; concentrator 512; composite structure 514; induction heating coil 600; AC power source 602; cold spot 604; induction heating coil 700; first coil 702; second coil 704; AC power source 706; first area 708; second area 710; induction heating coil 800; first coil 802; second coil 804; third coil 806; first AC power source 808; second AC power source 810; controller 812.

Claims

1. An anti-icing system (200) for a truss-reinforced wing (102) of an aircraft (100), the system (200) comprising: Wing (104); Support rod (106); a joint (110) coupling the support rod (106) to the wing (104) to form a structural truss (108) of the truss-reinforced wing (102); A magnetic receptor (110 / 404) disposed on or within the connector (110); and An induction heating coil (202) is disposed on or within the truss reinforced wing (102), wherein the induction heating coil (202) is configured to generate eddy currents within the magnetic susceptor (110) based on being driven by an alternating current excitation current, and wherein the eddy currents circulate through the magnetic susceptor (110), thereby causing Joule heating of the magnetic susceptor (110) to prevent ice accumulation on the joint (110).

2. The system (200) according to claim 1, wherein: The magnetic susceptor (110) is incorporated into the joint (110) that couples the support rod (106) to the wing (102).

3. The system (200) according to claim 1, wherein: The magnetic susceptor (110) includes an alloy having a Curie temperature less than a minimum temperature at which the material of the truss-reinforced wing (102) degrades due to excessive heating.

4. The system (200) according to claim 1, wherein: The magnetic permeability of the magnetic susceptor (110) varies throughout the magnetic susceptor (110).

5. The system (200) according to claim 4, wherein: The magnetic susceptor (110) is manufactured by additive manufacturing to achieve a variable magnetic permeability of the magnetic susceptor (110).

6. The system (200) according to claim 4, wherein: The outer portion (300) of the magnetic susceptor (110) has a higher magnetic permeability than the inner portion (302) of the magnetic susceptor (110).

7. The system (200) of claim 1, wherein: The truss reinforced wing (102) includes a composite skin (306), and wherein the induction heating coil (202) is arranged in the truss reinforced wing (102) so that the composite skin (306) is located between the induction heating coil (202) and the magnetic susceptor (110).

8. The system (200) according to claim 1, further comprising: An aerodynamic fairing (406) at least partially covers the joint (412), wherein the magnetic susceptor (404) is disposed on or within the aerodynamic fairing (406), and wherein the induction heating coil (424) is disposed below the aerodynamic fairing (406).

9. The system (200) according to claim 1, further comprising: A controller (204) is electrically coupled to the induction heating coil (202) and configured to drive the induction heating coil (202) using the AC excitation current of a fixed voltage and a fixed frequency.

10. The system (200) according to claim 1, further comprising: A controller (204) is electrically connected to the induction heating coil (202) and is configured to: 1) drive the induction heating coil (202) using the AC excitation current; 2) sense the impedance of the induction heating coil (202); and 3) adjust parameters of the AC excitation current based on the sensed impedance of the induction heating coil (202).

11. An anti-icing system (200) for a truss-reinforced wing (102) of an aircraft (100), the system (200) comprising: Wing (104); Support rod (106); a magnetic susceptor joint (110) coupling the support rod (106) to the wing (104) to form a structural truss (1108) of the truss-reinforced wing (102); an induction heating coil (202) disposed on the truss reinforced wing (102) or in the truss reinforced wing; and A controller (204) is electrically connected to the induction heating coil (202) and is configured to: Using an AC excitation current to drive the induction heating coil (202); sensing the impedance of the induction heating coil (202); and The parameters of the AC excitation current are adjusted based on the sensed impedance of the induction heating coil (202), wherein the induction heating coil (202) is configured to generate eddy currents inside the magnetic susceptor joint (110) based on being driven with the AC excitation current, and wherein the eddy currents circulate through the magnetic susceptor joint (110) to cause Joule heating of the magnetic susceptor joint (110) to prevent ice accumulation on the magnetic susceptor joint (110).

12. The system (200) according to claim 11, wherein: The magnetic susceptor joint (110) includes an alloy having a Curie temperature less than a minimum temperature at which the material of the truss reinforced wing (102) degrades due to excessive heating.

13. The system (200) of claim 11, wherein: The magnetic permeability of the magnetic susceptor joint (110) varies throughout the magnetic susceptor joint (110).

14. The system (200) according to claim 13, wherein: The magnetic susceptor joint (110) is manufactured by additive manufacturing to achieve a variable magnetic permeability of the magnetic susceptor joint (110).

15. The system (200) of claim 13, wherein: The outer portion (300) of the magnetic susceptor joint (110) has a higher magnetic permeability than the inner portion (302) of the magnetic susceptor joint (110).

16. The system (200) of claim 11, wherein: The truss reinforced wing (102) includes a composite skin (306), and wherein the induction heating coil (202) is arranged in the truss reinforced wing (102) so that the composite skin (306) is located between the induction heating coil (202) and the magnetic susceptor joint (110).

17. An anti-icing system (200) for a truss-reinforced wing (102) of an aircraft (100), the system (200) comprising: Wing (104); Support rod (106); a joint (110) coupling the support rod (106) to the wing (104) to form a structural truss (108) of the truss-reinforced wing (102); a magnetic susceptor (110) disposed on or within the truss-reinforced wing (102), wherein the magnetic permeability of the magnetic susceptor (110) varies throughout the magnetic susceptor (110); and An induction heating coil (202) is disposed on or within the truss reinforced wing (102), wherein the induction heating coil (202) is configured to generate eddy currents within the magnetic susceptor (110) based on driving with an AC excitation current, and wherein the eddy currents circulate through the magnetic susceptor (110), thereby causing Joule heating of the magnetic susceptor (110) to prevent ice accumulation on the joint (110).

18. The system (200) of claim 17, wherein: The magnetic susceptor (110) is incorporated into the joint (110) that couples the support rod (106) to the wing (104).

19. The system (200) of claim 17, wherein: The magnetic susceptor (110) is manufactured by additive manufacturing to achieve a variable magnetic permeability of the magnetic susceptor (110).

20. The system (200) of claim 17, wherein: The outer portion (300) of the magnetic susceptor (110) has a higher magnetic permeability than the inner portion (302) of the magnetic susceptor (110).

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