Patent ID: 12258118

DETAILED DESCRIPTION

The present application is directed to a thermal protection system and method for a vehicle moving through a free stream of air. The specific construction of the system and method therefor and the industry in which the system and method are implemented may vary. It is to be understood that the disclosure below provides a number of embodiments or examples for implementing different features of various embodiments. Specific examples of components and arrangements are described to simplify the present disclosure. These are merely examples and are not intended to be limiting.

By way of example, the disclosure below describes a thermal protection system and method for a vehicle, such as an aircraft, moving through a free stream of air. The system and method may be implemented by an original equipment manufacturer (OEM) in compliance with military and space regulations. It is conceivable that the disclosed system and method may be implemented in many other vehicle-type industries.

Referring toFIG.1, a schematic block diagram of a vehicle10moving through a free stream of air20is illustrated. The vehicle10embodies a thermal protection system100constructed in accordance with an example implementation. InFIG.1, the thermal protection system100includes a number of different material layers including a substrate layer110, an insulation layer130, and a honeycomb layer150.

Referring toFIG.2, a schematic elevational view of the thermal protection system100ofFIG.1is illustrated.FIG.2shows details of the layers110,130,150of the thermal protection system100. The substrate layer110may be an aerospace panel, and may include a metallic material (e.g., aluminum) capable of providing sufficient structural rigidity to support the load of the honeycomb layer150and the insulation layer130. A plenum114is adjacent to the substrate layer110. The plenum114directs coolant104, which may be a gas (e.g., air), from a coolant source (not shown) to the coolant feed holes112of the substrate layer110. The substrate layer110may have coolant feed holes112drilled therethrough. The coolant feed holes112may perforate the substrate layer110and may project a short distance into the insulation layer130(e.g., less than 25% of the total thickness of the insulation layer130), as shown inFIG.2. The coolant104passes from the plenum114through the coolant feed holes112and into and through the insulation layer130.

The insulation layer130may be coated with a thin layer (<100 mils) of hardness coat132that is applied to increase the adhesion of the porous ceramic foam of the insulation layer130to the substrate layer110. The hardness coat132on the insulation layer130is bonded (e.g., adhesively) to the substrate layer110. Bonding material140may be a room-temperature vulcanizing silicone adhesive. Other bonding materials are possible. The insulation layer130includes an open-cell, hyper-porous, ceramic, foam material. In some implementations, the insulation layer130includes ceramic fibers of various diameters and lengths bonded together at random to provide an open cell, hyper-porous foam. Pore size of the open-cell, hyper-porous, ceramic, foam material is less than about 250 microns. Other foam materials and pore sizes are possible. Structure and operation of foam materials are known and conventional and, therefore, will not be described.

The honeycomb layer150includes a first major surface152bonded at boundary interface134to the insulation layer130, and a second major surface154opposite the first major surface152and exposed at boundary interface136to the free stream of air20. Bonding material142may comprise a room-temperature vulcanizing silicone adhesive. Other bonding materials are possible. The honeycomb layer150comprises a phenolic resin with fibers dispersed throughout the phenolic resin. Other materials are possible.

It should be apparent that the insulation layer130is sandwiched between the substrate layer110and the honeycomb layer150. As such, coolant104passing through the coolant feed holes112of the substrate layer110can diffuse through both the insulation layer130and the honeycomb layer150to thermally protect the substrate layer110from heat produced by the vehicle10moving with velocity through the free stream of air20.

Referring toFIG.3, a top view, looking approximately along line3-3inFIG.2, is illustrated.FIG.3shows arrangement of a honeycomb cell structure156of the honeycomb layer150of the thermal protection system100. The honeycomb cell structure156comprises a plurality of honeycomb cells158. Each of the honeycomb cells158is hexagonal-shaped, and has a cell size and a cell thickness that are sufficient to block the free stream of air20from the insulation layer130that is underneath the honeycomb layer150inFIG.3. The cell size of each of the honeycomb cells158is about 0.375 inches and the cell thickness of each of the honeycomb layers is about 0.250 inches. Other cell sizes and cell thicknesses are possible.

In accordance with an example of the present disclosure, the presence of the honeycomb cell structure156shifts (i.e., offsets) a thermal boundary interface (i.e., the boundary interface134that is shown inFIG.2) from between the insulation layer130and the first major surface152of the honeycomb layer150to the second major surface154of the honeycomb layer150. By shifting a thermal boundary interface from the first major surface152to the second major surface154, surface cooling of the underlying insulation layer130and the substrate layer110is provided when coolant104passes through the coolant feed holes112of the substrate layer110into the insulation layer130as the vehicle10moves with velocity through the free stream of air20. Notably, transpirational cooling of the insulation layer130is improved when coolant104passes through the substrate layer110and into the insulation layer130by reducing the amount of coolant104needed to maintain temperature of the substrate layer110below a predetermined temperature limit.

Referring toFIG.4, a flow diagram400of a thermal protection method in accordance with an example implementation is illustrated. The thermal protection method is for a vehicle moving with velocity through a free stream of air. In block410, coolant is passed through coolant feed holes of a vehicle panel into an insulation layer. The process proceeds to block420in which coolant is diffused from the insulation layer through a honeycomb layer that is disposed between the insulation layer and a free stream of air to support transpirational cooling of the insulation layer and the vehicle panel. The transpirational cooling thermally protects the insulation layer and the vehicle panel. The process then ends.

In some embodiments, coolant comprising a gas is passed through the coolant feed holes of the vehicle panel into the insulation layer.

In some embodiments, coolant comprising air is passed through the coolant feed holes of the vehicle panel into the insulation layer.

In some embodiments, coolant from a coolant source is directed through a plenum to the coolant feed holes of the vehicle panel.

In some embodiments, an aerospace panel is thermally protected according to the disclosed thermal protection method.

A number of advantages are provided by the system and method disclosed herein. One advantage is that the honeycomb layer150provides free stream blocking (i.e., blocking the stream of air20from the underlying insulation layer130) while allowing transpirational cooling of the insulation layer130at the boundary interface134between the honeycomb layer150and the insulation layer130in a high convective heat flux environment.

Another advantage is that the free stream blocking provides surface temperature control at the boundary interface134to maintain temperature of the bonding material142and temperature of the honeycomb layer150below their temperature limits. As an example, the free stream blocking can reduce the amount of coolant104(e.g., up to a 50% reduction of coolant flow rate) required to provide thermal protection for a given temperature at the boundary interface134.

Yet another advantage is that a combination of the vehicle driving range and the vehicle payload capacity for a given vehicle can be increased since the amount of coolant104required is reduced. The result is not only a cost savings for the required amount of coolant104, but also an increased driving range and/or payload capacity for the given vehicle.

Examples of the disclosure may be described in the context of an aircraft manufacturing and service method1100, as shown inFIG.5, and an aircraft1102, as shown inFIG.6. During pre-production, the aircraft manufacturing and service method1100may include specification and design1104of the aircraft1102and material procurement1106. During production, component/subassembly manufacturing1108and system integration1110of the aircraft1102takes place. Thereafter, the aircraft1102may go through certification and delivery1112in order to be placed in service1114. While in service by a customer, the aircraft1102is scheduled for routine maintenance and service1116, which may also include modification, reconfiguration, refurbishment and the like.

Each of the processes of method1100may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of venders, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on.

As shown inFIG.6, the aircraft1102produced by example method1100may include an airframe1118with a plurality of systems1120and an interior1122. Examples of the plurality of systems1120may include one or more of a propulsion system1124, an electrical system1126, a hydraulic system1128, and an environmental system1130. Any number of other systems may be included.

The disclosed system and method may be employed during any one or more of the stages of the aircraft manufacturing and service method1100. As one example, components or subassemblies corresponding to component/subassembly manufacturing1108, system integration1110, and/or maintenance and service1116may be assembled using the disclosed system and method. As another example, the airframe1118may be constructed using the disclosed system and method. Also, one or more system examples, method examples, or a combination thereof may be utilized during component/subassembly manufacturing1108and/or system integration1110, for example, by substantially expediting assembly of or reducing the cost of an aircraft1102, such as the airframe1118and/or the interior1122. Similarly, one or more system examples, method examples, or a combination thereof may be utilized while the aircraft1102is in service, for example and without limitation, to maintenance and service1116.

Different examples of the system and method disclosed herein include a variety of components, features, and functionalities. It should be understood that the various examples of the system and method disclosed herein may include any of the components, features, and functionalities of any of the other examples of the system and method disclosed herein in any combination, and all of such possibilities are intended to be within the scope of the present disclosure.

The above-described system and method are described in the context of an aircraft. However, one of ordinary skill in the art will readily recognize that the disclosed system and method are suitable for a variety of applications, and the present disclosure is not limited to aircraft manufacturing applications. For example, the disclosed system and method may be implemented in various types of vehicles including, for example, helicopters, passenger ships, automobiles, marine products (boat, motors, etc.) and the like. Non-vehicle applications are also contemplated.

As an example, the disclosed system and method may be applied to a vehicle outer mold line, or to an internal mold line of inlets and nozzles for missiles or space vehicles, to protect underlying substructures in a high speed, high convective heat flux environment.

Although the above-description describes a system and method for thermally protecting an aerospace part (e.g., an aircraft panel) in the aviation industry in accordance with military and space regulations, it is contemplated that the system and method may be implemented to facilitate for thermally protecting a part in any industry in accordance with the applicable industry standards. The specific system and method can be selected and tailored depending upon the particular application.

Further, although various examples of disclosed embodiments have been shown and described, modifications may occur to those skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims.