Layered thermal metamaterials for the directing and harvesting of conductive heat

Bandaru, Prabhakar R.; Vemuri, Krishna P.; Canbazoglu, F. M.; Kapadia, R. S.

doi:10.1063/1.4916220

Cited by 37 publications

(32 citation statements)

References 93 publications

(131 reference statements)

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“…Recent realization of metamaterial devices based on cloaking and concentration effects for a static magnetic field [1][2][3][4][5] became one of the most up-to-date applications of transformation electrodynamics [6][7][8][9]. Analogous methods have been widely used to design devices of various type controlling manipulation of heat [10][11][12][13], acoustic [14], and material [15] waves. In [16], an analytical design of a multilayered composite structure allowing redirection (bending) of dc magnetic induction vector with respect to the applied external magnetic field has been presented.…”

Section: Introductionmentioning

confidence: 99%

Geometrically Tunable Transverse Electric Field in Multilayered Structures

Tarkhanyan

Niarchos

2017

Advances in Condensed Matter Physics

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Appearance of a transverse component in dc electric field with respect to the applied current is investigated in periodic multilayer composite structures made of nanometer-to-micrometer scale alternating layers of two different homogeneous and isotropic conducting materials. Dependence of the transverse electric field on geometrical orientation of the layers is examined using the coordinate transformation approach. Electric field bending angle as a function of the layers’ resistivity ratio is studied in detail. It is shown that both the direction and the magnitude of the field can be changed using orientation angle of the layers as a tuning parameter.

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Section: Introductionmentioning

confidence: 99%

Geometrically Tunable Transverse Electric Field in Multilayered Structures

Tarkhanyan

Niarchos

2017

Advances in Condensed Matter Physics

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“…[27][28][29][30][31][32][33][34][35][36][37] However, these devices were designed to cloak an object in a single physical fi eld.…”

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confidence: 99%

Invisible Sensors: Simultaneous Sensing and Camouflaging in Multiphysical Fields

et al. 2015

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maintaining its receiving ability. However, this technique is only valid for a single physical fi eld, e.g., an invisible electromagnetic sensor or an invisible acoustic detector. [2][3][4] Consequently, a single-functional sensor is invisible to an acoustic monitoring receiver, but it can be easily detected using a remote thermal imager. Is it possible to create a sensor that is invisible in multiple physical fi elds while maintaining the same sensing functionality? This is very challenging, if not impossible, to achieve, even using the concept of metamaterials, which are man-made composites that control waves and energy fl ux in unprecedented ways, resulting in exotic behaviors that are absent in nature. For example, electromagnetic metamaterials were proposed to manipulate electromagnetic waves and produce an invisibility cloak. [5][6][7] This pioneering idea motivated a number of significant applications, such as the wave concentrator and rotator. [8][9][10] Other than the electromagnetic waves, metamaterials have been created to manipulate other waves such as acoustic waves, [11][12][13] elastic waves, [ 14,15 ] magnetostatic fi elds, [ 16 ] and static forces.[ 17 ]More recently, metamaterials were presented that control the DC current [18][19][20][21][22][23][24][25][26] and the heat fl ux. [27][28][29][30][31][32][33][34][35][36][37] However, these devices were designed to cloak an object in a single physical fi eld.Advanced and multifunctional metamaterials are highly desirable for most practical applications. More recently, some attempts to cloak an object in multiple physical fi elds have been made, in particular, the bifunctional thermalelectric invisibility cloak [ 38 ] and independent manipulation [ 39 ] were proposed. Later, the fi rst experiment was carried out to simultaneously cloak an air cavity in the electric and thermal fi elds. [ 40 ] This sample was fabricated through a sophisticated man-made metamaterial structure with many holes drilled in a silicon plate that were, then, fi lled with poly(dimethylsiloxane) (PDMS). In our work, we found that natural materials with simple structure can also simultaneously manipulate multiphysical fi elds. We fabricated a device that acted as a "mask" for both thermal and electric fi elds and behaved as a multifunctional invisible sensor.To date, the theory of "cloaking a sensor" is only valid for a single physical fi eld. [ 1 ] In this study, we present the fi rst invisible sensor theory for static multiphysical-fi eld. This multiphysical invisible sensor has three features that distinguish it from conventional DC and thermal metamaterial devices, especially different from the bifunctional cloak for an air cavity. [ 40 ] First, we allow the sensor to "see through and behind" the cloaked region in multiphysical fi elds. As a result, the sensor is invisible and receives proportional incoming signals at the same time, and it is able to "open its eyes" behind the cloak to receive information from the outside multiphysical When a sensor is used to probe a ph...

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“…In particular, thermal shifters that guided heat fluxes along the anisotropic direction1132 were investigated by simulations and experiments113233343536. Multilayered and diagonally oriented composites of different thermal conductivities could generate thermal elements for a horizontal temperature gradient11, as well as the transient propagation of heat fluxes32.…”

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confidence: 99%

Tunable Multifunctional Thermal Metamaterials: Manipulation of Local Heat Flux via Assembly of Unit-Cell Thermal Shifters

Park

Kang

Lee

et al. 2017

Sci Rep

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Thermal metamaterials, designed by transformation thermodynamics are artificial structures that can actively control heat flux at a continuum scale. However, fabrication of them is very challenging because it requires a continuous change of thermal properties in materials, for one specific function. Herein, we introduce tunable thermal metamaterials that use the assembly of unit-cell thermal shifters for a remarkable enhancement in multifunctionality as well as manufacturability. Similar to the digitization of a two-dimensional image, designed thermal metamaterials by transformation thermodynamics are disassembled as unit-cells thermal shifters in tiny areas, representing discretized heat flux lines in local spots. The programmed-reassembly of thermal shifters inspired by LEGO enable the four significant functions of thermal metamaterials-shield, concentrator, diffuser, and rotator-in both simulation and experimental verification using finite element method and fabricated structures made from copper and PDMS. This work paves the way for overcoming the structural and functional limitations of thermal metamaterials.Active control of thermal energy through mediums is a significant subject with applicability in diverse fields, from fundamental physics to practical applications. Understanding thermal energy transport at nano-microscales mainly depends on the phonon distribution and contact interface of layers 1 . Manipulation of thermal energy transport at macroscales has been regarded as equivalent to the control of heat flux through the material, because of its diffusive nature through specific mediums at continuum scales 1,2 . Most research about macroscale thermal transport has focused on the development of bulk materials or mediums that promote thermal transport with superior thermal conductivity or suppress heat transfer with thermal insulation and grain boundaries 3,4 . The progress of micro-nanotechnologies has enabled advanced research into a new class of materials with desirable properties, by means of using embedded fillers in composite structures [5][6][7] . However, such methods have reached the limit for achieving breakthroughs in terms of active control of thermal energy near local spots in macroscales, since they inevitably depend on thermal properties of mediums.The development of metamaterials that are able to manipulate diverse physical properties using artificially designed structures have been introduced as a new approach to overcome previous limitations of transport phenomena through the mediums. Transformation optics was one of general approaches to design cloaking devices or optical waveguides [8][9][10][11][12][13][14] . This method was applicable to microwave frequencies as well 13 , and experimental verifications have been conducted in the visible wavelength region 15 . Furthermore, transformation thermodynamics has been recently extended to design new kinds of thermal metamaterials 16 , which actively control heat flux through diverse mediums in millimeter to centimeter scales, dominated b...

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Layered thermal metamaterials for the directing and harvesting of conductive heat

Cited by 37 publications

References 93 publications

Geometrically Tunable Transverse Electric Field in Multilayered Structures

Geometrically Tunable Transverse Electric Field in Multilayered Structures

Invisible Sensors: Simultaneous Sensing and Camouflaging in Multiphysical Fields

Tunable Multifunctional Thermal Metamaterials: Manipulation of Local Heat Flux via Assembly of Unit-Cell Thermal Shifters

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