Patent Application
20240142184
The present disclosure generally relates to heat transfer systems and, more specifically, to directing radiate heat from one object to other objects in heat transfer systems.
Multi-mode heat transfer systems generally use heat conduction and/or heat radiation to transfer heat from a heat source to one or more heat receiver devices positioned near the heat source. However, including a sufficient number of heat receiving devices to receive a desired percentage of heat from a heat source can require complicated designs and manufacturing.
The present disclosure addresses issues with heat transfer systems, and other issues related to transferring heat from a heat source to one or more objects.
In one form of the present disclosure, a multi-mode heat transfer system includes an emitter device with an inner core surrounded by an outer core having an outer surface and at least one emission surface disposed on the outer surface. Also, the at least one emission surface includes a thermal metamaterial configured to direct heat from the inner core in a desired direction to an object other than the emitter device.
In another form of the present disclosure, a multi-mode heat transfer system includes an emitter device with an inner core surrounded by an outer core having an outer surface, at least one emission surface in the form of a thermal metamaterial disposed on the outer surface, and at least two receiver devices spaced apart from the emitter device. In addition, the thermal metamaterial is configured to direct heat from the inner core in at least two different desired directions to the at least two receiver devices.
In still another form of the present disclosure, a multi-mode heat transfer system includes an emitter device with an inner core surrounded by an outer core having an outer surface, at least one planar emission surface in the form of a thermal metamaterial disposed on the outer surface, and at least two receiver devices spaced apart from the emitter device. And the thermal metamaterial is configured to direct heat from the inner core at a first angle +θ relative to a normal of the planar emission surface to one of the at least two receiver devices and a second angle −θ relative to the normal of the planar emission surface to another of the at least two receiver devices.
These and other features of the multi-mode heat transfer system will become apparent from the following detailed description when read in conjunction with the figures and examples, which are exemplary, not limiting.
The present teachings will become more fully understood from the detailed description and the accompanying drawings, wherein:
It should be noted that the figures set forth herein are intended to exemplify the general characteristics of the multi-mode heat transfer system of the present technology, for the purpose of the description of certain aspects. The figures may not precisely reflect the characteristics of any given aspect and are not necessarily intended to define or limit specific forms or variations within the scope of this technology.
The present disclosure provides multi-mode heat transfer systems and grating structures with thermal metamaterials for multi-mode heat transfer systems. The grating structures direct heat from a heat source in a predefined direction such that the heat is more efficiently provided to a heat receiver device. As used herein, the phrase “direct heat” refers to controlling, steering, or bending thermal radiation such that the thermal radiation propagates along a desired path or direction. Accordingly, the grating structures and/or multi-mode heat transfer systems according to the teachings of the present disclosure provide enhanced efficiency and/or reduced design complexity than traditional multi-mode heat transfer systems.
Referring to
The emitter device 100 is positioned to selectively transmit thermal radiation across a gap 180 towards the first receiver device 140 and/or the second receiver device 160. Also, the first receiver device 140 and/or the second receiver device 160 has a reduced temperature (i.e., is colder) than the emitter device 100. Accordingly, the heat transfer system 10, and other heat transfer systems disclosed herein, transfer and direct heat from an emitter device to an area (or volume) where the heat may be beneficial and/or may not cause harm. For example, a heat generated by a hot body engine may be directed, by an emitter device, to one or more receiver devices positioned in an engine compartment area that has ample intake of air to cool the heat. In another example, heat generated by a component in an aerospace application, such as a hot body solar receiver, may be directed, by an emitter device, to one or more receiver devices, such as a sail coupled to another component (e.g., a fly-by-light sailcraft) that requires or works more efficiently when receiving heat and associated directed radiated power.
In some variations, the emitter device 100 is generally cylindrical in shape as shown in
Referring now to
Still referring to
As used herein, the phrase “thermal metamaterial” refers to a material engineered to have a property not found in naturally occurring materials. In addition, the thermal metamaterial includes an assembly or array of multiple elements with dimensions that are less than wavelengths of thermal radiation emitted by the emission surface 240 such that the thermal radiation is steered (also known as being “bent”) in or directed to, or in, one or more desired directions.
In some variations the substrate 244s and the elements 244e are formed from the same material, while in other variations the substrate 244s and the elements 244e are formed from different materials. For example, in at least one variation the substrate 244s is formed from a high temperature ceramic such as silicon carbide (melting point=2730° C.) and the elements 244e are formed from a high temperature metallic material such as tungsten (melting point=3422° C.). And in some variations, the elements 244e are formed from a material with an extinction coefficient that is greater than an extinction coefficient of the substrate 244s. For example, silicon carbide has an extinction coefficient of about 0.0 for a radiation wavelength equal to 632.8 nanometers (nm) while tungsten has an extinction coefficient of about 2.9 for the same radiation wavelength. As used herein, the phrase “extinction coefficient” refers to the intrinsic property of a material that determines how strong the material absorbs or reflects radiation at a particular wavelength. Accordingly, the elements 244e formed from tungsten exhibit stronger absorption and thus enhanced emission (due to negligible transmission because of the absorption) of thermal radiation compared to the substrate 244s formed from silicon carbide.
In some variations, the grating structure 242 is configured to directed emitted thermal radiation in two or more different directions (i.e., at two or more different angles). For example, and with reference to
It should be understood that the first and second receiver devices 250a, 250b can be made of high-temperature applicable materials similar to the emission surface 240, but with a surface engineered to enhance absorption of thermal radiation rather than emission thereof. In addition, a grating structure similar to the grating structure 242 can be applied on an outer surface of the first and second receiver devices 250a, 250b, but a structure and/or dimensions designed to predominately absorb incoming thermal radiation normal to the surface.
Referring to
Still referring to
Referring to
The first emission surface 340a and the second emission surface 340b each include a grating structure 342 in the form of a thermal metamaterial configured to direct heat received from the inner core 310 in at least one desired direction. For example, in at least one variation the grating structure 342 includes a substrate 244s (
The heat transfer system 30 also includes three receiver devices 350, particularly, a first receiver device 350a, a second receiver device 350b, and a third receiver device 350c. The first receiver device 350a is positioned or aligned to receive thermal radiation emitted from the first emission surface 340a and directed at the angle −θ1, relative to the axis B1 (e.g., an axis normal to a planar surface of the first emission surface 340a), and thermal radiation from the second emission surface 340b and directed at the angle +θ2 relative to the axis B2 (e.g., an axis normal to a planar surface of the second emission surface 340b). The second receiver device 350b is positioned or aligned to receive thermal radiation emitted from the first emission surface 340a and directed at the angle +θ1 relative to the axis B1. And the third receiver device 350c is positioned or aligned to receive thermal radiation emitted from the second emission surface 340b and directed at the angle −θ2 relative to the axis B2.
In some variations, and as illustrated in
Referring now to
The first, second, third, and fourth emission surfaces 440a, 440b, 440c, 440d each have a grating structure (not labeled) in the form of a thermal metamaterial configured to direct heat received from the inner core 410 in at least one desired direction. For example, in at least one variation the grating structure includes a substrate 244s with a plurality of elements 244e (
The heat transfer system 40 also includes four receiver devices 450, particularly, a first receiver device 450a, a second receiver device 450b, a third receiver device 450c, and a fourth receiver device 450d. The first receiver device 450a is positioned or aligned to receive thermal radiation emitted from the first emission surface 440a directed at the angle −θ1 relative to axis C1 and thermal radiation emitted from the fourth emission surface 440d at the angle +θ4 relative to axis C4. The second receiver device 450b is positioned or aligned to receive thermal radiation emitted from the first emission surface 440a directed at the angle +θ1 relative to axis C1 and thermal radiation emitted from the second emission surface 440b at the angle −θ2 relative to axis C2. The third receiver device 450c is positioned or aligned to receive thermal radiation emitted from the second emission surface 440b directed at the angle +θ2 relative to axis C2 and thermal radiation emitted from the third emission surface 440c at the angle −θ3 relative to axis C3. And the fourth receiver device 450d is positioned or aligned to receive thermal radiation emitted from the third emission surface 440c directed at the angle +θ3 relative to axis C3 and thermal radiation emitted from the fourth emission surface 440d at the angle −θ4 relative to axis C4.
Accordingly, heat transfer systems with emitter devices with grating structures in the form of thermal metamaterials according to the teachings of the present disclosure provide enhanced heat transfer by directing heat from a heat source in a desired focused direction towards a heat receiving device. In addition, the emitter devices according to the teachings of the present disclosure direct heat in at least two different focused directions such that at least two different receiver devices can receive heat from a single emitter device.
The preceding description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A or B or C), using a non-exclusive logical “or.” It should be understood that the various steps within a method may be executed in different order without altering the principles of the present disclosure. Disclosure of ranges includes disclosure of all ranges and subdivided ranges within the entire range.
The headings (such as “Background” and “Summary”) and sub-headings used herein are intended only for general organization of topics within the present disclosure and are not intended to limit the disclosure of the technology or any aspect thereof. The recitation of multiple forms or variations having stated features is not intended to exclude other forms or variations having additional features, or other forms or variations incorporating different combinations of the stated features.
As used herein the terms “about” and “generally” when related to numerical values herein refers to known commercial and/or experimental measurement variations or tolerances for the referenced quantity. In some variations, such known commercial and/or experimental measurement tolerances are +/−10% of the measured value, while in other variations such known commercial and/or experimental measurement tolerances are +/−5% of the measured value, while in still other variations such known commercial and/or experimental measurement tolerances are +/−2.5% of the measured value. And in at least one variation, such known commercial and/or experimental measurement tolerances are +/−1% of the measured value.
As used herein, the terms “comprise” and “include” and their variants are intended to be non-limiting, such that recitation of items in succession or a list is not to the exclusion of other like items that may also be useful in the devices and methods of this technology. Similarly, the terms “can” and “may” and their variants are intended to be non-limiting, such that recitation that a form or variation can or may comprise certain elements or features does not exclude other forms or variations of the present technology that do not contain those elements or features.
The broad teachings of the present disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the specification and the following claims. Reference herein to one aspect, or various aspects means that a particular feature, structure, or characteristic described in connection with a form or variation is included in at least one form or variation. The appearances of the phrase “in one variation” or “in one form” (or variations thereof) are not necessarily referring to the same form or variation. It should be also understood that the various method steps discussed herein do not have to be carried out in the same order as depicted, and not each method step is required in each form or variation.
The foregoing description of the forms or variations has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular form or variation are generally not limited to that particular form or variation, but, where applicable, are interchangeable and can be used in a selected form or variation, even if not specifically shown or described. The same may also be varied in many ways. Such variations should not be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
While particular forms or variations have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended, are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.
