Patent Application
20190337592
A wide variety of potential practical and useful embodiments will be more readily understood through the following detailed description of certain exemplary embodiments, with reference to the accompanying exemplary drawings in which:
Certain exemplary embodiments can provide a system, which comprises a ship flight deck (e.g., and aluminum flight deck). The system further comprises a plurality of heat pipes. Each of the plurality of heat pipes is installed in a cavity defined by a ship flight deck. Each of the plurality of heat pipes can be surrounded by a high heat capacity material such as a Phase Change Material.
Roles of amphibious ships (e.g., combat ships) can be to support the expanded capability of twenty-first century expeditionary strike platforms such as the Marine variant of the V-22 Osprey rotorcraft (“MV-22”) and the F-35B Joint Strike Fighter. The MV-22 is capable of Vertical Takeoff and Landing (“VTOL”), and the F-35B is capable of Short runway Take-Off and Vertical Landing (“STOVL”).
MV-22 and F-35B aircraft operations have exposed the flight decks to relatively high thermo-mechanical loads. Engine combustion produces a hot gas plume that exits the nacelle and is often directed to impinge a surface of the flight deck. Rotor downwash, which comprises cool air, entrains the gas plume but might be insufficient to maintain the deck temperature below thermo-mechanical degradation limits. In addition to takeoffs and landings, flight operations may utilize engines that run on idle while the aircraft is on the ship deck. In contrast, the F-35B currently utilizes a single hot exhaust duct located towards the rear of the aircraft and a cool air lift fan. Thermal signatures of the MV-22 and F-35B differ but heat transfer to deck surfaces is significant in both cases.
The introduction of the MV-22 to amphibious assault ships has resulted in flight deck warping during flight operations. Buckling of steel flight decks has been observed and documented. Subsequent assessments of the thermal loads imposed by the landing of the F-35B Joint Strike Fighter on these ships indicate unacceptably severe heating during landing. Because the localized region of heating is surrounded by unheated deck plate and is welded to a deck support structure (longitudinal and transverse stiffening beams), mechanically constrained thermal expansion is accommodated by deck plate buckling.
With the introduction of aluminum flight decks, such as those used on the
Expeditionary Fast Transport ships (EPF) (formerly designated Join High Speed Vessel (JHSV)), new challenges have emerged. Compared to steel flight decks, aluminum's lower yield strength can lead to significant plastic deformation and substantially permanent undulations in the deck surface, which can impact subsequent flight deck operations. The impact of the induced stresses may worsen over time as the hot exhaust gases subject the deck to thermal annealing, further lowering its yield strength as the benefits of using heat treated aluminum is lost. Additionally, the low cycle, high stress fatigue associated with repeated landings will reduce the anticipated lifespan of the deck.
Certain exemplary embodiments can mitigate the effects of the aforementioned thermal loading that is applied by aircraft such as, for example, VTOL and STOVL aircraft.
Certain exemplary embodiments provide a Thermal Management System (“TMS”), which makes use of high thermal conductivity heat pipes to spread heat from highly localized regions to areas where the heat can be effectively dissipated.
The heat pipe concept is based upon the evaporation of a working fluid near a heat source that sets up a region of elevated pressure in a hermetically sealed system. The latent heat of evaporation allows for heat energy to be transported down the pressure gradient as a vapor stream until it condenses at cooler regions in the pipe. There the heat pipe releases the latent heat of vaporization at a location well suited for removal. Replenishment of the condensed working fluid to the evaporator region is driven by a liquid pressure gradient in a saturated, porous wick (or microchannels), which lines walls of the heat pipe. The evaporation, vapor flow (heat transport), and condensation of the working fluid spreads heat from local hot spots, lowering temperatures and thermally induced stress gradients. Effective thermal conductivities many times greater than copper can be attained via use of heat pipes.
In an exemplary embodiment, sealed heat pipes are fitted within the open core of the extruded aluminum deck structure as shown in
Heat from hot exhaust gases impinging the flight deck are transported by thermal conduction through the flight deck and into the filler material. The filler material stores this thermal energy as sensible heat and, therefore, rises in temperature. Heat from the filler material is then transported through the heat pipe wall to initiate evaporation of the filler material and startup of the heat pipe. The heat pipe acts as a heat spreader, transporting heat from localized hot spots and spreading the heat throughout the flight deck where the heat can be removed by convection and radiation, significantly reducing maximum surface temperatures when compared to other exemplary decks. The overall design of the TMS including dimensions, working fluid, and boundary conditions will ultimately determine the flight deck's temperature during VTOL/STOVL operations.
In an exemplary embodiment (illustrated in
A space between the heat pipes and the surrounding deck core and face sheets can be substantially filled with a Phase Change Material (“PCM”). The purpose of the filler material is twofold: (1) store thermal energy as latent heat in situations where short bursts of thermal energy might not activate startup of heat pipe or if heat pipe is in starting from a frozen state and (2) to provide a thermal conduction pathway between the flight deck and heat pipe. A PCM can absorb or release large amounts of heat at (near) constant temperature during solid to liquid and/or liquid to solid transitions. Initially, the PCM can store thermal energy as sensible heat up until phase transition. The PCM can store large amounts of thermal energy as latent heat during the phase transition. The PCM is chosen such that the transition (i.e. melting point) occurs within the operating temperature range but is below the prescribed maximum temperature designated for the flight deck. The PCM can be organic or inorganic, including eutectic material and/or solid-solid PCMs.
Certain exemplary embodiments can provide a system, which comprises a ship flight deck. The system further comprises a plurality of heat pipes. Each of the plurality of heat pipes is installed in a cavity defined by a ship flight deck. Each of the plurality of heat pipes can be surrounded by a high heat capacity material such as a Phase Change Material. Each cavity can define a geometric cross-section, such as substantially circular, oblong, triangular, square, or any polygon, etc.
Each of the plurality of heat pipes can comprise tubing, such as tubing fabricated from aluminum, stainless steel, copper, any other metal or alloy, and/or that comprises a polymer etc. Each of the plurality of heat pipes can comprise aluminum tubing with a nickel-plated interior. Each of the plurality of heat pipes can comprise a porous wick liner that is constructed to be substantially saturated with water in operation.
In embodiments comprising a PCM, the PCM can absorb energy via a solid to liquid phase change. In embodiments comprising a PCM, the PCM can release energy via a liquid to solid phase change. In embodiments comprising a PCM, the PCM can be:
When the following terms are used substantively herein, the accompanying definitions apply. These terms and definitions are presented without prejudice, and, consistent with the application, the right to redefine these terms during the prosecution of this application or any application claiming priority hereto is reserved. For the purpose of interpreting a claim of any patent that claims priority hereto, each definition (or redefined term if an original definition was amended during the prosecution of that patent), functions as a clear and unambiguous disavowal of the subject matter outside of that definition.
Still other substantially and specifically practical and useful embodiments will become readily apparent to those skilled in this art from reading the above-recited and/or herein-included detailed description and/or drawings of certain exemplary embodiments. It should be understood that numerous variations, modifications, and additional embodiments are possible, and accordingly, all such variations, modifications, and embodiments are to be regarded as being within the scope of this application.
Thus, regardless of the content of any portion (e.g., title, field, background, summary, description, abstract, drawing figure, etc.) of this application, unless clearly specified to the contrary, such as via explicit definition, assertion, or argument, with respect to any claim, whether of this application and/or any claim of any application claiming priority hereto, and whether originally presented or otherwise:
Moreover, when any number or range is described herein, unless clearly stated otherwise, that number or range is approximate. When any range is described herein, unless clearly stated otherwise, that range includes all values therein and all subranges therein. For example, if a range of 1 to 10 is described, that range includes all values therebetween, such as for example, 1.1, 2.5, 3.335, 5, 6.179, 8.9999, etc., and includes all subranges therebetween, such as for example, 1 to 3.65, 2.8 to 8.14, 1.93 to 9, etc.
When any claim element is followed by a drawing element number, that drawing element number is exemplary and non-limiting on claim scope. No claim of this application is intended to invoke paragraph six of 35 USC 112 unless the precise phrase “means for” is followed by a gerund.
Any information in any material (e.g., a United States patent, United States patent application, book, article, etc.) that has been incorporated by reference herein, is only incorporated by reference to the extent that no conflict exists between such information and the other statements and drawings set forth herein. In the event of such conflict, including a conflict that would render invalid any claim herein or seeking priority hereto, then any such conflicting information in such material is specifically not incorporated by reference herein.
Accordingly, every portion (e.g., title, field, background, summary, description, abstract, drawing figure, etc.) of this application, other than the claims themselves, is to be regarded as illustrative in nature, and not as restrictive, and the scope of subject matter protected by any patent that issues based on this application is defined only by the claims of that patent.
This application claims priority to, and incorporates by reference herein in its entirety, pending U.S. Provisional Patent Application Ser. No. 62/655624 (Attorney Docket No. 1022-013), filed Apr. 10, 2018.
| Number | Date | Country | |
|---|---|---|---|
| 62655624 | Apr 2018 | US |
