U.S. patent application number 15/714579 was filed with the patent office on 2018-02-01 for multi-layer phononic crystal thermal insulators.
This patent application is currently assigned to Elwha LLC. The applicant listed for this patent is Elwha LLC. Invention is credited to Paul G. Allen, Jeffrey A. Bowers, Kenneth G. Caldeira, William D. Duncan, Roderick A. Hyde, Muriel Y. Ishikawa, Edward K.Y. Jung, Jordin T. Kare, John Latham, Eric C. Leuthardt, Nathan P. Myhrvold, Thomas J. Nugent,, Jr., Stephen H. Salter, Clarence T. Tegreene, David B. Tuckerman, Thomas A. Weaver, Charles Whitmer, Lowell L. Wood,, Jr., Victoria Y.H. Wood.
Application Number | 20180031171 15/714579 |
Document ID | / |
Family ID | 50931236 |
Filed Date | 2018-02-01 |
United States Patent
Application |
20180031171 |
Kind Code |
A1 |
Allen; Paul G. ; et
al. |
February 1, 2018 |
MULTI-LAYER PHONONIC CRYSTAL THERMAL INSULATORS
Abstract
A thermal insulator includes a plurality of layers. At least
some of the layers include phononic crystals having a phononic
bandgap, wherein heat transporting phonons within a selected range
of frequencies are substantially blocked by each phononic crystal
layer. The plurality of layers thermally isolate a first region
from a second region, wherein the first region is at one end of the
plurality of layers and the second region is at the other end of
the plurality of layers.
Inventors: |
Allen; Paul G.; (Mercer
Island, WA) ; Bowers; Jeffrey A.; (Bellevue, WA)
; Caldeira; Kenneth G.; (Redwood City, CA) ;
Duncan; William D.; (Sammamish, WA) ; Hyde; Roderick
A.; (Redmond, WA) ; Ishikawa; Muriel Y.;
(Livermore, CA) ; Jung; Edward K.Y.; (Bellevue,
WA) ; Kare; Jordin T.; (San Jose, CA) ;
Latham; John; (Boulder, CO) ; Leuthardt; Eric C.;
(St. Louis, MO) ; Myhrvold; Nathan P.; (Medina,
WA) ; Nugent,, Jr.; Thomas J.; (Bellevue, WA)
; Salter; Stephen H.; (Edinburgh, GB) ; Tegreene;
Clarence T.; (Mercer Island, WA) ; Tuckerman; David
B.; (Lafayette, CA) ; Weaver; Thomas A.; (San
Mateo, CA) ; Whitmer; Charles; (North Bend, WA)
; Wood,, Jr.; Lowell L.; (Bellevue, WA) ; Wood;
Victoria Y.H.; (Livermore, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Elwha LLC |
Bellevue |
WA |
US |
|
|
Assignee: |
Elwha LLC
Bellevue
WA
|
Family ID: |
50931236 |
Appl. No.: |
15/714579 |
Filed: |
September 25, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15014944 |
Feb 3, 2016 |
9772062 |
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15714579 |
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13720717 |
Dec 19, 2012 |
9291297 |
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15014944 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B82Y 30/00 20130101;
B82Y 20/00 20130101; Y10T 428/24942 20150115; B82Y 40/00 20130101;
Y10T 428/24752 20150115; Y10T 428/24802 20150115; Y10T 29/49826
20150115; B32B 2307/206 20130101; B32B 2307/304 20130101; F16L
59/029 20130101; F16L 59/028 20130101 |
International
Class: |
F16L 59/02 20060101
F16L059/02 |
Claims
1. A method for providing thermal insulation, comprising: providing
a plurality of layers, at least some of the layers comprising
phononic crystals having a phononic bandgap, wherein heat
transporting phonons within a selected range of frequencies are
substantially blocked by each layer comprising phononic crystals;
and arranging the plurality of layers into a multilayer structure,
wherein the layers comprising phononic crystals are arranged in a
sequence having at least one of an increasing or a decreasing order
according to a phononic bandgap frequency associated with each of
the layers comprising phononic crystals to form a continuous
gradation of phononic bandgaps.
2. The method of claim 1, wherein each layer comprises a different
material combination than every other layer.
3. The method of claim 1, wherein at least one layer comprises
voids defined within the layer in order to alter that layer's
phononic bandgap.
4. The method of claim 1, wherein phononic crystals associated with
at least one layer comprise a periodic array of two different solid
materials.
5. The method of claim 1, wherein phononic crystals associated with
a first layer have different lattice spacing than phononic crystals
associated with a second layer.
6. The method of claim 1, wherein at least one layer comprises at
least one of doping atoms, nanoparticles, nanowires, nanocrystals,
nanopores, lithographically defined features, nano-machined nano
holes, nanofibers, or nanofilaments.
7. The method of claim 1, wherein at least one layer comprises at
least one of 1-dimensional crystals, 2-dimensional crystals, or
3-dimensional crystals.
8. A method for providing a thermal insulator, comprising:
providing a plurality of layers, at least some of the layers
comprising phononic crystals having a phononic bandgap, wherein
heat transporting phonons within a selected range of frequencies
are substantially blocked by each layer comprising phononic
crystals; and arranging the plurality of layers into a sequence
having random phononic bandgap jumps, the random phononic bandgap
jumps counteracting a rethermalization of energy as the heat
transporting phonons propagate through the plurality of layers.
9. The method of claim 8, wherein each layer comprises a different
material combination than every other layer.
10. The method of claim 8, wherein at least one layer comprises
voids defined within the layer in order to alter that layer's
phononic bandgap.
11. The method of claim 8, wherein phononic crystals associated
with at least one layer comprise a periodic array of two different
solid materials.
12. The method of claim 8, wherein phononic crystals associated
with a first layer have different lattice spacing than phononic
crystals associated with a second layer.
13. The method of claim 8, wherein at least one layer comprises at
least one of doping atoms, nanoparticles, nanowires, nanocrystals,
nanopores, lithographically defined features, nano-machined nano
holes, nanofibers, or nanofilaments.
14. The method of claim 8, wherein at least one layer comprises at
least one of 1-dimensional crystals, 2-dimensional crystals, or
3-dimensional crystals.
15. An insulated system, comprising: a plurality of laterally
arranged insulators each comprising: a plurality of layers, at
least some of the layers comprising phononic crystals having a
phononic bandgap, wherein heat transporting phonons with a selected
range of frequencies are substantially blocked by each layer
comprising phononic crystals; wherein the plurality of layers are
arranged into a sequence having random phononic bandgap jumps, the
random phononic bandgap jumps counteracting a rethermalization of
energy as the heat transporting phonons propagate through the
plurality of layers; wherein each of the insulators are coupled to
at least one other insulator.
16. The system of claim 15, wherein at least one phononic crystal
layer is coupled to an apparatus.
17. The system of claim 16, wherein the apparatus includes a
turbine blade.
18. The system of claim 16, wherein the apparatus includes an
electronic device.
19. The system of claim 15, wherein at least one phononic crystal
layer is configured for use with a heat sensor.
20. The system of claim 15, wherein at least one phononic crystal
layer comprises at least one of doping atoms, nanoparticles,
nanowires, nanocrystals, nanopores, lithographically defined
features, nano-machined nano holes, nanofibers, or nanofilaments.
Description
CROSS REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 15/014,944, filed Feb. 3, 2016, which is a continuation of U.S.
application Ser. No. 13/720,717, filed Dec. 19, 2012, the entire
disclosures of which are incorporated herein by reference in their
entireties for any and all purposes.
BACKGROUND
[0002] Phononic crystals are synthetic materials that are formed by
arranging materials in a periodic array or lattice structure. The
periodic structure of phononic crystals has profound effects on
wave propagation throughout the crystals. Periodic variation of the
acoustic properties of the material can introduce phononic bandgaps
into the crystals, in which certain frequencies of phonons cannot
propagate. It is possible to adjust the acoustic and thermal
properties of the crystals by adjusting the phononic bandgaps.
SUMMARY
[0003] One exemplary embodiment relates to a thermal insulator. The
thermal insulator includes a plurality of layers, at least some of
the layers including phononic crystals having a phononic bandgap,
wherein heat transporting phonons within a selected range of
frequencies are substantially blocked by each phononic crystal
layer. The plurality of layers thermally isolate a first region
from a second region, wherein the first region is at one end of the
plurality of layers and the second region is at the other end of
the plurality of layers.
[0004] Another exemplary embodiment relates to a thermally
insulated system. The system includes a plurality of laterally
arranged thermal insulators each including a plurality of layers,
at least some of the layers comprising phononic crystals having a
phononic bandgap, wherein heat transporting phonons within a
selected range of frequencies are substantially blocked by each
phononic crystal layer. The plurality of layers inhibits heat flow
therethrough and each of the thermal insulators are coupled to at
least one other thermal insulator.
[0005] Another exemplary embodiment relates to a method for
providing thermal insulation. The method includes providing a
plurality of layers, at least some of the layers comprising
phononic crystals having a phononic bandgap, and arranging the
plurality of layers into a multilayer structure, wherein the
plurality of layers thermally isolates a first region from a second
region, wherein the first region is at one end of the plurality of
layers and the second region is at the other end of the plurality
of layers.
[0006] The invention is capable of other embodiments and of being
carried out in various ways. Alternative exemplary embodiments
relate to other features and combinations of features as may be
generally recited in the claims.
[0007] The foregoing is a summary and thus by necessity contains
simplifications, generalizations and omissions of detail.
Consequently, those skilled in the art will appreciate that the
summary is illustrative only and is not intended to be in any way
limiting. Other aspects, inventive features, and advantages of the
devices and/or processes described herein, as defined solely by the
claims, will become apparent in the detailed description set forth
herein and taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE FIGURES
[0008] The invention will become more fully understood from the
following detailed description taken in conjunction with the
accompanying drawings wherein like reference numerals refer to like
elements, in which:
[0009] FIG. 1 is a schematic diagram of multilayer structure
comprised of phononic crystals, and a heat path is shown according
to an exemplary embodiment.
[0010] FIG. 2 is a schematic diagram of multilayer structure
comprised of phononic crystals, and a heat path is shown according
to an exemplary embodiment.
[0011] FIG. 3 is a schematic diagram of multilayer structure
comprised of phononic crystals, and a heat path is shown according
to an exemplary embodiment.
[0012] FIG. 4 is a schematic diagram of phononic crystal layer is
shown according to an exemplary embodiment.
[0013] FIG. 5 is a schematic diagram of a thermal shielding,
comprising multilayer structures of phononic crystals, shown
according to an exemplary embodiment.
[0014] FIG. 6 is a schematic diagram of a thermal shielding coupled
to a turbine blade, shown according to an exemplary embodiment.
[0015] FIG. 7 is a schematic diagram of a thermal insulator coupled
to an electronic device, shown according to an exemplary
embodiment.
[0016] FIG. 8 is a schematic diagram of multilayer structure
comprised of phononic crystal layers and non-phonic crystal layers,
and a heat path is shown according to an exemplary embodiment.
DETAILED DESCRIPTION
[0017] Before turning to the figures, which illustrate the
exemplary embodiments in detail, it should be understood that the
application is not limited to the details or methodology set forth
in the description or illustrated in the figures. It should also be
understood that the terminology is for the purpose of description
only and should not be regarded as limiting.
[0018] Referring generally to the Figures, systems and methods of
using phononic crystals for thermal insulators are shown. Phononic
crystals are composite materials that are formed with periodic
variations of material properties. For example, the variations can
be of density, mass, elasticity, etc. Variations may also be of the
crystal structure of the phononic crystals Variations of the
crystal structure may be one-dimensional, two-dimensional, or
three-dimensional variations, as needed for a particular
application. Such variations can be used to introduce phononic
bandgaps into the material due to destructive interference of
phonon propagation through the material. The spacing and the
arrangement of the variations and phononic crystal interfaces
allows for the tuning of the bandgap of a layer. Thermal energy may
be transported by phonons, however, phonons of a wavelength at a
frequency corresponding to a bandgap cannot propagate
therethrough.
[0019] The thermal conductivity of a solid includes contributions
from the collection of available phonon modes. A classical
formulation of this for a simple .omega.(k) dispersion relation and
modal distribution D(.omega.), is:
.lamda. = 2 3 k B T 2 V .intg. 0 .omega. D v ( .omega. ) 2 .tau. (
.omega. ) D ( .omega. ) .omega. 2 e .omega. / k B T ( e .omega. / k
B T - 1 ) 2 d .omega. ##EQU00001##
[0020] See Chantrenne, P., and Barrat, J. L., Analytical Model for
the Thermal Conductivity of Nanostructures, Superlattices and
Microstructures, Vol. 35, 173-186 (2004).
[0021] While this conductivity integral (and more complex analogs)
shows that all phonon frequencies, .omega., contribute to the
thermal conductivity, the largest contribution generally occurs at
frequencies near the peak of the Boltzman distribution, i.e., for
frequencies, .omega..about.k.sub.BT/z,22 . Accordingly, use of a
phononic crystal with a bandgap such that such frequencies are
blocked will be effective in reducing the thermal conductivity. The
potential of using phononic crystals to reduce thermal conductivity
by forming bandgaps near the peak of the Boltzman distribution has
been previously discussed. (See U.S. Pat. No. 8,094,023 to El-Kady
et al., and P. E. Hopkins et al., Phonon Considerations in the
Reduction of Thermal Conductivity in Phononic Crystals, Applied
Physics A, Vol. 103, 575-579 (2011).) Achieving a large reduction
in the thermal conductivity depends on the ability to block a wide
range of frequencies covering the peak of the conductivity
integrand, typically frequencies near k.sub.BT/. For operation near
room temperature, this corresponds to THz frequencies, and
accordingly to photonic crystals having nanometer scale lattice
spacings. Because the spectral width of the conductivity integrand
is broad, it is useful to block a wide range of frequencies
covering as much of the spectral peak of the integrand as
possible.
[0022] Phononic crystals can achieve full or partial bandgaps for
certain phononic modes. Partial bandgaps (i.e., blocking some, but
not all, wavevectors at a given frequency) and density-of-state
reductions can be useful in reducing thermal conductivity,
particularly if the effects occur over a wide range of the
releva20nt phononic frequencies. Complete bandgaps (i.e., blocking
all wavevectors at a given frequency), will be even more effective,
depending on the range of frequencies over which the gap extends. A
phononic crystal achieves a bandgap due to destructive interference
of the vibrations of materials within its crystal lattice; this
interference is effective only for a limited range of frequencies.
When comparing the width of the band gap, to a reference frequency
based on the phononic crystal's lattice spacing, typical bandgaps
are of order 10%. Phononic crystals having wider, .about.50%,
bandgaps have been designed, for instance, by optimizing the layout
and acoustic mismatch of the crystals' constituents (see Lai, Y.,
The Study of Band Gap Engineering for Phononic Crystals and Gap
Structures in Phononic Quasicrystals, Ph.D. Thesis, The Hong Kong
University of Science and Technology, Dept. of Physics, (2005)), or
by using phononic crystal slabs (see Khelif et al., Complete Band
Gaps in Two-Dimensional Phononic Crystal Slabs, Phys. Rev. E, Vol.
74, 046610, 1-5 (2006)). However, to maximize thermal conductivity
reductions, it is desirable to achieve band gaps over even wider
portions of the spectrum, more than can be achieved for a single
phononic crystal.
[0023] Phononic crystals can be formed using a variety of different
physical layouts and materials. They may employ periodic
arrangements of two (or three or more) different materials. While
one of the materials is generally a solid, the other(s) may be a
gas (or voids), may be a liquid, or may be another solid material.
The phononic crystal may be one-dimensional, comprising a periodic
arrangement of planar layers. The phononic crystal may be
two-dimensional, comprising a rectangular or hexagonal arrangement
of one or more materials in a matrix of another material. The
phononic crystal may be three-dimensional, comprising a periodic
array defined by different symmetries or Bravais Lattices (e.g.,
cubic, hexagonal, tetragonal, rhombohedral, orthorhombic). The
phononic crystal can be a quasicrystal, without complete
periodicity; bandgaps in phononic quasicrystals are discussed in
the aforementioned Ph.D. Thesis by Lei.
[0024] Phononic crystals may be layered in sets to form a
multilayer structure, with each phononic crystal layer having a
corresponding bandgap. The multilayer structure may be in the form
of a superlattice and may be comprised of layers of phononic
crystals by themselves, or in combination with layers of other
non-phononic crystal material. The multilayer structure may be used
as a thermal insulator. Such an insulator may function in air, a
vacuum, or other medium, etc. Additionally, acoustic bandgaps may
be introduced in addition to the phononic bandgaps of the layers
for both vibrational and thermal insulation. Other vibrational
isolation layers may also be introduced into the multiplayer
structure. In one embodiment, the insulator comprises a sequence of
discrete phononic crystal layers, one after the other. The phononic
crystal layers may contact each other, or they may be separated by
layers of vibrationally mismatched material, so as to form a
sequence of distinct phononic crystal slabs. In another embodiment,
the insulator comprises a single, gradually varying, phononic
crystal in which the lattice spacing changes from one side of the
insulator to the other. Lattice spacing of phononic crystal layers
may also be the same or different.
[0025] The sequence of layers can have monotonic (increasing or
decreasing) bandgaps, can have large (up or down) bandgap jumps,
can have random bandgap jumps, etc., and a variety of frequencies
of phonons may be blocked. The sequence of layers may include
non-phononic crystal layers interspersed there between. In one
embodiment there are ten layers within a multilayer structure of an
insulator. The insulator is designed to block a certain thermal
spectrum. The bandgaps of the ten layers correspond to different
wavelengths of the thermal spectrum, and the ten layers are
randomly distributed throughout the multilayer structure. In
another embodiment there are five layers within a multilayer
structure of an insulator. The insulator is designed to block a
certain thermal spectrum. The bandgaps of the five layers
correspond to different wavelengths of the thermal spectrum, and
the five layers are distributed throughout the multilayer structure
in order of increasing bandgap frequency. The frequencies
corresponding to the bandgaps of layers may be selected to
correspond to a particular application. For example, certain heat
transporting phonons may be desired to be blocked, or certain heat
transporting phonons may be desired to be allowed to propagate. The
thermal frequency spectrum for that temperature range may be
analyzed and used to design an insulator for a particular
temperature range (e.g., the bandgaps within the multilayer
structure may be selected according to the frequency spectrum of
the temperature range).
[0026] Additionally, the multilayer structures or individual layers
may be laterally positioned in order to channel heat flow along
desired paths, or away from other paths. The multilayer structures
or individual layers may also be arranged to enhance anisotropic
heat flow, enhancing the ratio of along-layer flow to that of
across-layer flow. The bandgaps or layers may also be laterally
patterned to thermally-shield specific regions of space more than
other regions.
[0027] Referring to FIG. 1 a schematic diagram of multilayer
structure 100 is shown according to an exemplary embodiment.
Multilayer structure 100 is shown as having three layers of
phononic crystals, 102, 104, and 106. Although depicted as only
three layers, it should be understood that the scope of the present
disclosure is not limited to any particular number of layers.
Phononic crystal layer 102, phononic crystal layer 104, and
phononic crystal layer 106 each have phononic bandgaps.
[0028] In one embodiment, the layers are arranged such that the
bandgaps of each layer overlap the bandgap of another layer. For
example, the energy required to bridge the bandgap of one layer may
overlap the energy required to bridge the gap of a second layer. In
another embodiment, the layers are arranged such that the bandgaps
of each layer do not overlap the bandgaps of other layers. In
another embodiment, the bandgaps of layers 102, 104, and 106 are
increasing or decreasing to form a continuous gradation of
bandgaps. In another embodiment, the bandgaps of layers 102, 104,
and 106 are monotonically spaced. In another embodiment, the
bandgaps of layers 102, 104, and 106 are randomly distributed
throughout multilayer structure 100. As an example, a random
distribution of bandgaps may be used to counteract the
rethermalization of energy as phonons propagate therethrough. In
another embodiment, the layers are in an order such that there are
bandgap jumps throughout multilayer structure 100.
[0029] FIG. 1 is further shown as having regions 108 and 110, and
heat path 112. Region 108 is at one end of multilayer structure
100, and region 110 is at the other end. Heat path 112 is shown in
a direction that is normal to layers 102, 104, and 106, however,
alternative heat paths are envisioned. In one embodiment, the
bandgaps of layers 102, 104, and 106 correspond to a certain
temperature range that is desired to be blocked. By blocking
thermal transporting phonons having frequencies within the
temperature range, region 108 is thermally isolated from region
110.
[0030] In one embodiment, the bandgaps of layers 102-106 are
selected to facilitate the propagation of only certain phonon
frequencies and modes. This may be used to allow temperature
sensing of selected temperatures through multilayer structure 100.
As an example, multilayer structure 100 may be coupled to the
thermal sensor of a device. Multilayer structure 100 may thermally
isolated the device, while allowing the thermal sensor to detect
heat flow corresponding to the allowed phonon frequencies of the
layers.
[0031] Referring to FIG. 2, a schematic diagram of multilayer
structure 200 is shown according to an exemplary embodiment.
Multilayer structure 200 is shown as having three layers of
phononic crystals, 202, 204, and 206. Phononic crystal layer 202,
phononic crystal layer 204, and phononic crystal layer 206 each
have phononic bandgaps. Multilayer structure 200 further contains
regions 208 and 210, and heat path 212. Region 208 is at one end of
multilayer structure 200 and region 210 is at the other end. Heat
path 212 is within the plane of layer 204 of multilayer structure
200. It should be understood, that the scope of the present
disclosure is not limited to a certain orientation or number of
heat paths. Heat path 212 may be used to direct heat to third
region 214. For example, this may be used to channel heat along
heat path 212 to a desired location. In another example, heat path
212 may be used to channel heat away from an undesired location
(e.g., region 208, region 210, etc.). Each layer may or may not be
electrically conducting along the heat path (e.g., heat path
212).
[0032] Referring to FIG. 3 a schematic diagram of multilayer
structure 300 is shown according to an exemplary embodiment.
Multilayer structure 300 is shown as having four layers of phononic
crystals, 302, 304, 306, and 308. Phononic crystal layer 302,
phononic crystal layer 304, phononic crystal layer 306, and
phononic crystal layer 308 each have phononic bandgaps. Each layer
in multilayer structure 300 may be of a same or different material
combination and be of different thickness and may be highly
structured. Each layer in multilayer structure 300 may also include
other materials to form its bandgap. In one embodiment, layer 302
contains doping atoms. In another embodiment, layer 304 contains
nanoparticles. In another embodiment, layer 306 contains nanowires.
In another embodiment, layer 308 contains nanocrystals. In another
embodiment, layer 302 contains nanopores. In another embodiment,
layer 304 contains lithographically defined features. In another
embodiment, layer 306 contains nano-machined nano holes. In another
embodiment, layer 306 contains nanofibers. In another embodiment,
layer 306 contains nanofilaments. It should be understood that a
layer may contain any number of materials or voids (e.g., doping
atoms, nanowires, nanocrystals, nanopores, quantum wells, quantum
dots, lithographically defined features, nano-machined nano
vacancies or holes, nanofibers, nanofilaments, etc.). The selection
of materials of a layer may depend on a desired bandgap.
[0033] Referring to FIG. 4, a schematic diagram of phononic crystal
layer 400 is shown according to an exemplary embodiment. Phononic
crystal layer 400 may be a layer within a multilayer structure
(e.g., multilayer structure 300 of FIG. 3). Phononic crystal layer
400 further contains removed material locations 402. Phononic
crystal layer 400 may be partially removed to create voids within
the layer. Such voids may contribute to the formation of the
layer's corresponding bandgap. Removed of material may be of the
nanoscopic scale or microscopic scale, etc. Removed material
locations 402 may be in highly ordered one-dimensional,
two-dimensional, or three-dimensional structures. Removed material
locations 402 may be randomly, but uniformly distributed. Phononic
crystal layer 400 further contains dislocation 404 of layer
material. As an example, dislocations of a layer's material may be
used in forming the bandgap of the layer. In one embodiment, the
bandgap of phononic crystal layer 400 is formed through removal of
material at the nanoscale. In another embodiment, the bandgap of
phononic crystal layer 400 is formed through creating dislocations
in the layer material. In another embodiment, the bandgap of
phononic crystal layer 400 is formed through both removal of layer
material and dislocations of the layer material.
[0034] Referring to FIG. 5, a schematic diagram of thermal
shielding 500 is shown according to an exemplary embodiment.
Thermal shielding 500 includes multilayer structures of phononic
crystals 502, 504, and 506, that are coupled. Multilayer structures
502, 504, and 506 may be multilayer structures as described herein
(e.g., multilayer structure 100 of FIG. 1, etc.). Each layer 508,
510, and 512 of multilayer structure 502 may be a layer as
described herein (e.g. layers 102, 104, and 106 of FIG. 1, layers
202, 204, and 206 of FIG. 2, layers 302, 304, 306, and 308 of FIG.
3, etc.). Multilayer structures 504 and 506 also contain layers as
described herein. Thermal shielding 500 may contain any number of
multilayer structures which contain any number of layers. In one
embodiment, multilayer structures 502, 504, and 506 are so formed
as to be conformable or moldable. In another embodiment, multilayer
structures 502, 504, and 506 are capable of being machined and
formed into a desired shape. In one embodiment, multilayer
structures 502, 504, and 506 are laterally patterned in order to
impede heat transfer perpendicular to the layers of multilayer
structures 502, 504, and 506. The patterning can be used to channel
heat flow along desired paths (e.g., heat path 212 of FIG. 2). For
example, thermal shielding 500 may be configured for use on an
aircraft. In another example, thermal shielding may be coupled to
an electronic device in a hostile environment.
[0035] Referring to FIG. 6, thermal shielding 602 is shown as
coupled to a blade of turbine 600. Thermal shielding 602 may be
thermal shielding as described herein (e.g., thermal shielding 500
of FIG. 5). Thermal shielding 602 contains a plurality of
multilayer structures 604. Each multilayer structure 604 may be a
multilayer structure as described herein (e.g., multilayer
structure 100 of FIG. 1, multilayer structure 200 of FIG. 2,
multilayer structure 300 of FIG. 3, etc.). Each layer 606, 608, and
610 of multilayer structure 604 may be a layer as described herein
(e.g. layers 102, 104, and 106 of FIG. 1, layers 202, 204, and 206
of FIG. 2, layers 302, 304, 306, and 308 of FIG. 3, etc.). In one
embodiment, turbine 600 is a steam turbine and thermal shielding
602 is used to insulate the blades of turbine 600. Thermal
shielding 602 is further used to direct thermal energy away from
the blades. In another embodiment, turbine 600 is a gas turbine and
thermal shielding 602 is used to insulate the blades of turbine
600. Thermal shielding 602 may be used to direct thermal energy
along a desired path.
[0036] Referring to FIG. 7, a schematic diagram of system 700 is
shown according to an exemplary embodiment. System 700 includes
insulator 702, which is shown as coupled to electronic device 701.
Electronic device 701 contains thermal sensor 708. Insulator 702 is
constructed from a multilayer structure as described herein (e.g.,
multilayer structure 100 of FIG. 1, multilayer structure 200 of
FIG. 2, multilayer structure 300 of FIG. 3, etc.). Each layer 710,
712, and 714 of insulator 702 may be a layer as described herein
(e.g. layers 102, 104, and 106 of FIG. 1, layers 202, 204, and 206
of FIG. 2, layers 302, 304, 306, and 308 of FIG. 3, etc.). Thermal
energy 704 is shown as flowing along heat path 706, away from
electronic device 701. Alternatively, layers 710, 712, and 714 may
be configured with bandgaps selected to transmit only certain
phonon frequencies and modes in order to allow thermal sensor 708
to sense temperatures through insulator 702. As an example, thermal
sensor 708 may be used as part of a temperature monitoring circuit
on electronic device 701.
[0037] Referring to FIG. 8 a schematic diagram of multilayer
structure 800 is shown according to an exemplary embodiment.
Multilayer structure 800 is shown as having two layers of phononic
crystals, 802 and 806, and a non-phononic crystal layer 804.
Although depicted as only three layers, it should be understood
that the scope of the present disclosure is not limited to any
particular number of phononic crystal and non-phononic crystal
layers. Phononic crystal layers 802 and 806 each have phononic
bandgaps. Phononic crystal layers 802 and 806 of multilayer
structure 800 may also be arranged as described herein, e.g., as in
multilayer structure 100 of FIG. 1, multilayer structure 200 of
FIG. 2, etc. Non-phononic crystal layer 804 may be arranged in any
order with respect to phononic crystal layers 802 and 806. In one
embodiment, the placement of non-phononic crystal layer 804 is
determined based on a certain application of multilayer structure
800.
[0038] FIG. 8 is further shown as having regions 808 and 810, and
heat path 812. Region 808 is at one end of multilayer structure
800, and region 810 is at the other end. Heat path 812 is shown in
a direction that is normal to layers 802, 804, and 806, however,
alternative heat paths and orientations are envisioned. In one
embodiment, the bandgaps of layers 802 and 806 correspond to a
certain temperature range that is desired to be blocked. By
blocking thermal transporting phonons having frequencies within the
temperature range, region 808 is thermally isolated from region
810. In another embodiment, the bandgaps of layers 802 and 806 are
selected to facilitate the propagation of only certain phonon
frequencies and modes.
[0039] It is important to note that the construction and
arrangement of the elements of the systems and methods as shown in
the exemplary embodiments are illustrative only. Although only a
few embodiments of the present disclosure have been described in
detail, those skilled in the art who review this disclosure will
readily appreciate that many modifications are possible (e.g.,
variations in sizes, dimensions, structures, shapes and proportions
of the various elements, values of parameters, mounting
arrangements, use of materials, colors, orientations, etc.) without
materially departing from the novel teachings and advantages of the
subject matter recited. For example, elements shown as integrally
formed may be constructed of multiple parts or elements. It should
be noted that the elements and/or assemblies of the enclosure may
be constructed from any of a wide variety of materials that provide
sufficient strength or durability, in any of a wide variety of
colors, textures, and combinations. Additionally, in the subject
description, the word "exemplary" is used to mean serving as an
example, instance or illustration. Any embodiment or design
described herein as "exemplary" is not necessarily to be construed
as preferred or advantageous over other embodiments or designs.
Rather, use of the word exemplary is intended to present concepts
in a concrete manner. Accordingly, all such modifications are
intended to be included within the scope of the present inventions.
The order or sequence of any process or method steps may be varied
or re-sequenced according to alternative embodiments. Any
means-plus-function clause is intended to cover the structures
described herein as performing the recited function and not only
structural equivalents but also equivalent structures. Other
substitutions, modifications, changes, and omissions may be made in
the design, operating conditions, and arrangement of the preferred
and other exemplary embodiments without departing from scope of the
present disclosure or from the spirit of the appended claims.
[0040] The present disclosure contemplates methods, systems and
program products on any machine-readable media for accomplishing
various operations. The embodiments of the present disclosure may
be implemented using existing computer processors, or by a special
purpose computer processor for an appropriate system, incorporated
for this or another purpose, or by a hardwired system. Embodiments
within the scope of the present disclosure include program products
comprising machine-readable media for carrying or having
machine-executable instructions or data structures stored thereon.
Such machine-readable media can be any available media that can be
accessed by a general purpose or special purpose computer or other
machine with a processor. By way of example, such machine-readable
media can comprise RAM, ROM, EPROM, EEPROM, CD-ROM or other optical
disk storage, magnetic disk storage or other magnetic storage
devices, or any other medium which can be used to carry or store
desired program code in the form of machine-executable instructions
or data structures and which can be accessed by a general purpose
or special purpose computer or other machine with a processor. When
information is transferred or provided over a network or another
communications connection (either hardwired, wireless, or a
combination of hardwired or wireless) to a machine, the machine
properly views the connection as a machine-readable medium. Thus,
any such connection is properly termed a machine-readable medium.
Combinations of the above are also included within the scope of
machine-readable media. Machine-executable instructions include,
for example, instructions and data which cause a general purpose
computer, special purpose computer, or special purpose processing
machines to perform a certain function or group of functions.
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