Heat exchanger with fluidized particle bed

Abstract

A cold plate for a heat exchanger system can include a base in thermal communication with a heat load, one or more walls extending from the base, a first fluid path through the cold plate, a plurality of particles disposed within the first fluid path, or any combination thereof. The first fluid path can have an inlet and an outlet and / or be bounded on at least two sides by the walls. The plurality of particles can be confined within the first fluid path fluidically between the inlet and the outlet. The plurality of particles can be loosely disposed within a vertical portion of the first fluid path.

Description

HEAT EXCHANGER WITH FLUIDIZED PARTICLE BEDCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 520,576 filed August 18, 2023, the entire contents of which are incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure relates generally to heat exchangers and more specifically relates to cold plate heat exchangers.BACKGROUND

[0003] As manufacturers continue to develop increasingly advanced chip architecture, fitting more and more transistors on small wafers of silicon, power density greatly increases. With high density applications, air cooling does not provide sufficient heat flux to maintain chip temperature, which leads to overheating and performance throttling. Direct to chip, two-phase cooling can be required for the highest density cooling applications.

[0004] Forced two-phase cooling, using a cold plate, has shown to be an effective way to achieve high critical heat flux (i.e. , the maximum heat per unit area that a given device can reasonably cool, or the heat flux at which boiling ceases to be an effective form of transferring heat from a solid surface to a liquid). Two-phase cooling achieves high critical heat fluxes by boiling off coolant / refrigerant and maintaining nearly uniform temperatures throughout the cold plate. Heat is removed as vapor leaves the outlet and is condensed using heat rejection equipment.

[0005] Although forced two-phase cooling can be effective at maintaining almost completely uniform temperature gradients, boiling liquid at the surface of a cold plate’s wall(s) can produce vapor that becomes slightly superheated. The expansion of the vapor prevents re-wetting and causes temporary dry spots to form. Vapor in these regions has a lower thermal conductivity andcan superheat before it bubbles away, which leads to a reduction in heat transfer and elevated surface temperatures.SUMMARY

[0006] Applicant has created new and useful devices, systems and methods for heat exchangers, such as cold plates. In at least one embodiment, a cold plate for a heat exchanger system according to the disclosure can include a base configured to be disposed in thermal communication with a heat load, a first pair of walls extending from the base, a first fluid path through the cold plate, a plurality of particles disposed within the first fluid path, or any combination thereof. In at least one embodiment, the first fluid path can have an inlet and an outlet and / or can be bounded on at least two sides by the first pair of walls. In at least one embodiment, the plurality of particles can be confined within the first fluid path fluidically between the inlet and the outlet. In at least one embodiment, the plurality of particles can be loosely disposed within the first fluid path. In at least one embodiment, the first fluid path can have a vertical portion, and the plurality of particles can be confined within the vertical portion.

[0007] In at least one embodiment, the plurality of particles can be thermally conductive particles. In at least one embodiment, the plurality of particles can include metal particles. In at least one embodiment, the plurality of particles can be configured to increase a transfer rate of heat from the first pair of walls to a two-phase cooling fluid. In at least one embodiment, the plurality of particles can be configured to fluidize when a cooling fluid is moved through the first fluid path, such as a one-phase subcooled cooling fluid or a two-phase saturated cooling fluid. In at least one embodiment, the thermally conductive particles can be configured to transfer heat, such as through particle-wall collision and / or particle-particle collision. In at least one embodiment, the plurality of particles can be configured to resist vapor insulation of at least a portion of one or more walls or other surfaces duringtwo-phase cooling of the cold plate. In at least one embodiment, the plurality of particles can be configured to cause or increase turbulent flow in at least a portion of the first fluid path.

[0008] In at least one embodiment, the cold plate can have a fin extending from the base. In at least one embodiment, one wall of the first pair of walls can be a sidewall of the fin. In at least one embodiment, the cold plate can have a plurality of fins extending from the base, a plurality of fluid paths through the cold plate, and a plurality of particles disposed within each of the plurality of fluid paths. In at least one embodiment, each of the plurality of fluid paths can have an inlet and an outlet and / or be bounded on at least one side by a sidewall of one of the plurality of fins. In at least one embodiment, the particles can be confined fl uidical ly between the inlet and the outlet of each of the plurality of fluid paths.

[0009] In at least one embodiment, the cold plate can have an inlet manifold in fluid communication with the inlet of the first fluid path, an outlet manifold in fluid communication with the outlet of the first fluid path, an inlet filter disposed fluidically downstream of the inlet manifold, an outlet filter disposed fluidically upstream of the outlet manifold, or any combination thereof. In at least one embodiment, the plurality of particles can be confined fluidically between the inlet filter and the outlet filter. In at least one embodiment, each particle of the plurality of particles can have a major dimension, the inlet filter can have an inlet filter size, and the outlet filter can have an outlet filter size. In at least one embodiment, the major dimension can be larger than the inlet filter size and / or the outlet filter size. In at least one embodiment, the inlet filter size and the outlet filter size can be different. In at least one embodiment, the inlet filter size and / or the outlet filter size can be configured to allow a cooling fluid to flow through the cold plate while the plurality of particles is confined within the first fluid path fluidically between the inlet and the outlet.

[0010] In at least one embodiment, the cold plate can have a first heat transfer rate when a first cooling fluid is moved through the first fluid path at a first flow rate without the plurality of particles disposed within the first fluid path. In at least one embodiment, the cold plate can have a second heat transfer rate when the first cooling fluid is moved through the first fluid path at the first flow rate with the plurality of particles disposed within the first fluid path. In at least one embodiment, the second heat transfer rate can be greater than the first heat transfer rate.

[0011] In at least one embodiment, the cold plate can have a first critical heat flux when a first cooling fluid is moved through the first fluid path at a first flow rate without the plurality of particles disposed within the first fluid path. In at least one embodiment, the cold plate can have a second critical heat flux when the first cooling fluid is moved through the first fluid path at the first flow rate with the plurality of particles disposed within the first fluid path. In at least one embodiment, the second critical heat flux can be greater than the first critical heat flux.

[0012] In at least one embodiment, the plurality of particles can be configured to increase a transfer rate of heat from the first pair of walls to a two-phase cooling fluid. In at least one embodiment, the plurality of particles can be configured to fluidize when a two-phase cooling fluid or other cooling fluid is moved through the first fluid path. In at least one embodiment, the plurality of particles can include metal particles.

[0013] In at least one embodiment, a heat exchanger according to the disclosure can include one or more cold plates. In at least one embodiment, any or all of the cold plates can include a base configured to be disposed in thermal communication with a heat load, a plurality of fins extending from the base, a plurality of fluid paths through the cold plate, with each of the plurality of fluid paths having an inlet and an outlet, a plurality of particle sets, wherein each of the plurality of particle sets is disposed within a corresponding one ofthe plurality of fluid paths, a prime mover configured to circulate a two-phase cooling fluid through the plurality of fluid paths at a velocity for fluidizing each of the plurality of particle sets, or any combination thereof. In at least one embodiment, each of the plurality of fluid paths through the cold plate can have a vertically oriented portion. In at least one embodiment, the particle sets can be confined within the vertically oriented portions by filters. In at least one embodiment, the fluidized particle sets can resist vapor insulation of one or more heat transfer surfaces during cooling of the one or more cold plates.

[0014] In at least one embodiment, a cooling method according to the disclosure can include disposing a cold plate in thermal communication with a heat load, moving a two-phase cooling fluid through a fluid path of the cold plate, fluidizing a particle set disposed within the fluid path, or any combination thereof.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a block diagram of one of many embodiments of a heat exchanger system according to the disclosure.

[0016] FIG. 2 is a sectional view of one of many embodiments of a portion of the heat exchanger system of FIG. 1 , taken along line AA.

[0017] FIG. 3 is a sectional view of another one of many embodiments of a portion of the heat exchanger system of FIG. 1 , taken along line AA.

[0018] FIG. 4 is a sectional view of still another one of many embodiments of a portion of the heat exchanger system of FIG. 1 , taken along line AA.

[0019] FIG. 5 is a side view of one of many embodiments of a portion of a heat exchanger system according to the disclosure.

[0020] FIG. 6 is a front view of one of many embodiments of a portion of a heat exchanger system according to the disclosure.

[0021] FIG. 7 is a simplified block diagram of one of many embodiments of a portion of a heat exchanger system according to the disclosure.

[0022] FIG. 8 is a front view of one of many embodiments of a portion of a heat exchanger system according to the disclosure.

[0023] FIG. 9 is a simplified representation of one of many embodiments of a fluid flow path of a heat exchanger system according to the disclosure.

[0024] FIG. 10 is another simplified representation of one of many embodiments of a fluid flow path of a heat exchanger system according to the disclosure.

[0025] FIG. 11 is a simplified representation of vapor pockets within a fluid flow path of a heat exchanger system according to the disclosure.

[0026] FIG. 12 is a simplified representation of particles reacting with vapor pockets within a fluid flow path of a heat exchanger system according to the disclosure.

[0027] FIG. 13 is a simplified representation of particles within a fluid flow path of a heat exchanger system according to the disclosure.

[0028] FIG. 14 is an exemplary chart illustrating aspects of the relationship between wall heat flux and wall superheat within a fluid flow path of a heat exchanger system, without particles therein, according to the disclosure.

[0029] FIG. 15 is an exemplary chart illustrating aspects of the relationship between wall heat flux and wall superheat within a fluid flow path of a heat exchanger system, with particles therein, according to the disclosure.DETAILED DESCRIPTION

[0030] The figures described above and the written description of specific structures and functions below are not presented to limit the scope of what Applicant has invented or the scope of the appended claims. Rather, the figures and written description are provided to teach any person skilled in the art to make and use the inventions for which patent protection is sought. Those skilled in the art will appreciate that not all features of a commercial embodiment of the inventions are described or shown for the sake of clarity and understanding. Persons of skill in this art will also appreciate that the development of an actual commercial embodiment incorporating aspects of the present inventions will require numerous implementation-specific decisions to achieve the developer’s ultimate goal for the commercial embodiment. Such implementation-specific decisions may include, and likely are not limited to, compliance with system-related, business-related, government-related and other constraints, which may vary by specific implementation, location and from time to time. While a developer’s efforts might be complex and time-consuming in an absolute sense, such efforts would be, nevertheless, a routine undertaking for those of skill in this art having benefit of this disclosure. It must be understood that the inventions disclosed and taught herein are susceptible to numerous and various modifications and alternative forms.

[0031] The use of a singular term, such as, but not limited to, “a,” is not intended as limiting of the number of items. Also, the use of relational terms, such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” and the like are used in the written description for clarity in specific reference to the figures and are not intended to limit the scope of the inventions or the appended claims. The terms “including” and “such as” are illustrative and not limitative. The terms “couple,” “coupled,” “coupling,” “coupler,” and like terms are used broadly herein and can include any method or device for securing, binding, bonding, fastening, attaching, joining, insertingtherein, forming thereon or therein, communicating, or otherwise associating, for example, mechanically, magnetically, electrically, chemically, operably, directly or indirectly with intermediate elements, one or more pieces of members together and can further include without limitation integrally forming one functional member with another in a unity fashion. The coupling can occur in any direction, including rotationally. Further, all parts and components of the disclosure that are capable of being physically embodied inherently include imaginary and real characteristics regardless of whether such characteristics are expressly described herein, including but not limited to characteristics such as axes, ends, inner and outer surfaces, interior spaces, tops, bottoms, sides, boundaries, dimensions (e.g., height, length, width, thickness), mass, weight, volume and density, among others.

[0032] Applicant has created new and useful devices, systems and methods for heat exchangers, such as cold plates. The inventions disclosed herein allow for higher critical heat fluxes and generally improve thermal performance of heat exchangers, such as cold plates. In at least one embodiment, a heat exchanger, such as a cold plate, utilizes a bed of conductive particles fluidized or suspended in fluid by refrigerant flow. Such fluidized particles can support or improve heat transfer in one or more ways, such as by causing disruption of vapor formations and dry-out spots; disrupting plausible mechanisms governing critical heat flux for flow boiling; disrupting vapor blanket separation of a hot wall or other surface from bulk flow; disrupting dense bubble clusters adjacent to a hot surface; disrupting bubble coalescence near liquid sublayers near a hot surface; colliding with bubble formations on the surface of a wall, breaking them up and mixing them into the bulk fluid; re-wetting dry spots on a wall in the event of interfacial separation of a liquid surface and a hot wall, such as by breaking the surface tension of the vapor; colliding with a wall and conducting heat, thereby providing wall-to- particle conduction; colliding with other particles and conducting heat, thereby providing particle-to-particle conduction; boosting heat transfer area; providingnucleation sites to encourage boiling at lower temperatures; generally increasing turbulence; or any combination thereof. Such particles can be carried away from the wall by the fluid and can be cooled away from critical areas.

[0033] FIG. 1 is a block diagram of one of many embodiments of a heat exchanger system according to the disclosure. FIG. 2 is a sectional view of one of many embodiments of a portion of the heat exchanger system of FIG. 1 , taken along line AA. FIG. 3 is a sectional view of another one of many embodiments of a portion of the heat exchanger system of FIG. 1 , taken along line AA. FIG. 4 is a sectional view of still another one of many embodiments of a portion of the heat exchanger system of FIG. 1 , taken along line AA. FIG. 5 is a side view of one of many embodiments of a portion of a heat exchanger system according to the disclosure. FIG. 6 is a front view of one of many embodiments of a portion of a heat exchanger system according to the disclosure. FIG. 7 is a simplified block diagram of one of many embodiments of a portion of a heat exchanger system according to the disclosure. FIG. 8 is a front view of one of many embodiments of a portion of a heat exchanger system according to the disclosure. FIG. 9 is a simplified representation of one of many embodiments of a fluid flow path of a heat exchanger system according to the disclosure. FIG. 10 is another simplified representation of one of many embodiments of a fluid flow path of a heat exchanger system according to the disclosure. FIG. 11 is a simplified representation of vapor pockets within a fluid flow path of a heat exchanger system according to the disclosure. FIG. 12 is a simplified representation of particles reacting with vapor pockets within a fluid flow path of a heat exchanger system according to the disclosure. FIG. 13 is a simplified representation of particles within a fluid flow path of a heat exchanger system according to the disclosure. FIG. 14 is an exemplary chart illustrating aspects of the relationship between wall heat flux and wall superheat within a fluid flow path of a heat exchanger system, without particles therein, according to the disclosure. FIG. 15 is anexemplary chart illustrating aspects of the relationship between wall heat flux and wall superheat within a fluid flow path of a heat exchanger system, with particles therein, according to the disclosure. FIGS. 1-15 are described in conjunction with one another.

[0034] In at least one embodiment, a heat exchanger or heat exchanger system 200 according to the disclosure can include one or more cold plates 100 for cooling one or more heat loads, such as electronic components utilized in a data center. In at least one embodiment, a cold plate 100 according to the disclosure can include one or more bases 102 configured to be disposed in thermal communication with one or more heat loads 202, two or more walls 104 extending from the base 102, one or more fluid paths 106 through the cold plate 100, a plurality of particles 108 disposed within one or more of the fluid paths 106, or any combination thereof. In at least one embodiment, the heat exchanger system 200 can include one or more secondary heat exchangers 204 to discharge heat extracted from the heat load 202 by the cold plate 100. In at least one embodiment, the heat exchanger system 200 can include one or more prime movers 206, such as a pump or a compressor, to circulate one or more cooling fluids or working fluids, such as a two-phase cooling fluid, through the fluid path(s) 106 of the cold plate 100.

[0035] As illustrated in, e.g., FIGS. 1-8 for exemplary purposes, in at least one embodiment, the cold plate 100 can be a solid-to-fluid heat exchanger, such as a direct to chip heat exchanger for direct thermal communication with heat-generating electronic components. However, this need not be the case, and other embodiments are contemplated. For example, in at least one embodiment, cold plate 100 can be or include a fluid- to-fluid heat exchanger, an air-to-fluid heat exchanger, or another type of heat exchanger according to an implementation of the disclosure. Similarly, in at least one embodiment, the heat exchanger system 200 or cold plate 100 can utilize a two-phase cooling fluid, or refrigerant. However, phase-changecooling is not necessarily required and, in at least one embodiment, the heat exchanger system 200 or cold plate 100 can utilize a single-phase cooling fluid, or a combination of two or more cooling fluids.

[0036] In at least one embodiment, the fluid path 106 can have one or more inlets 112, such as from an inlet manifold, and one or more outlets 114, such as to an outlet manifold, and / or can be bounded on one or more sides by one or more of the walls 104, such as a sidewall of the cold plate 100, a sidewall of one of the fins 122, another heat transfer surface of the cold plate 100, or a combination thereof. In at least one embodiment, the particles 108 can be confined within the fluid path 106 or a portion thereof fluidically between the inlet 112 and the outlet 114, such as by an inlet filter 116 and / or an outlet filter 1 18. In at least one embodiment, the particles 108 can be loosely disposed, entrained, or suspended, such as fluidically, within the fluid path 106. In at least one embodiment, the particles 108 can be loosely disposed within the fluid path 106. In at least one embodiment, the fluid path 106 can have a vertical portion, and the particles 108 can be confined within the vertical portion.

[0037] In at least one embodiment, one or more tanks, storage compartments and / or recycle paths can be in fluid communication with one or more of the fluid paths 106 for storing and / or routing at least a portion of the particles 108, such as to resist or prevent clogging during cooling operations. For example, in at least one embodiment, the outlet filter 1 18 can be slanted or angled with respect to the fluid path 106 or can otherwise be configured to shed or deflect particles 108 impacting thereon towards or into a tank upstream of the outlet filter 1 18 or a recycle path 130. In at least one embodiment, the recycle path or circuit 130 can route the particles towards the inlet end of the fluid path 106 or otherwise into the fluid path 106 upstream of the outlet filter, thereby repositioning or reusing the particles 108 for cooling operations and / or preventing the particles 108 from clogging the outlet filter118. In at least one embodiment, a pump, compressor, conveyor, or other mechanism 132 can be used to clear the outlet filter 1 18 and / or to recycle the particles 108.

[0038] In at least one embodiment, the particles 108 can be thermally conductive particles, which can be made from any thermally conductive material required or desired for an implementation of the disclosure. In at least one embodiment, the particles 108 can include metal particles. In at least one embodiment, the particles 108 can include conductive metal particles, such as copper, aluminum, steel, brass, titanium, lead, alloys of any of the foregoing, or any combination thereof. In at least one embodiment, the particles 108 can be made in whole or in part of an oxidation-resistant or corrosion-resistant metal or alloy (e.g., stainless steel), which can help reduce any potential for oxidation or corrosion to negatively affect the heat transfer process. However, this need not be the case, and materials with relatively low corrosion resistance can be utilized as well.

[0039] In at least one embodiment, the particles 108 can be macroscopic in scale. For example, in at least one embodiment, the particles 108 can have diameters or other cross-sectional dimensions from .1 mm to 6 mm, or other dimension(s) according to an implementation of the disclosure. In at least one embodiment, one or more of the particles 108 can be spherical, cylindrical, polyhedral, oblong, irregularly shaped, or other shape(s) according to an implementation of the disclosure. As other examples, one or more of the particles 108 can be of a spiked ball shape or, for instance, can be star-shaped or jack-shaped (i.e., resembling a six-pointed star with rounded, pointed or otherwise shaped points).

[0040] In at least one embodiment, the physical properties of the particles 108 for a given implementation of the disclosure can depend, at least in part, on the type of working fluid or cooling fluid being utilized (and vice versa), which can be or include any particle properties and / or fluid type(s)according to an implementation of the disclosure. For instance, in at least one embodiment, chip throttling can be set at or around 90 °C, and an implementation of the disclosure can be configured accordingly. As another example, in at least one embodiment, working fluid temperatures for relatively advanced, high density chips can be at or around 50 °C (or lower), and an implementation of the disclosure can be configured accordingly. Similarly, a wide variety of refrigerants or coolants can be utilized, as required or desired for a given implementation of the disclosure. For example, common two- phase fluids utilized in IT cooling applications can include fluorochemical or fluorocarbon fluids, but other fluids can be utilized in one or more embodiments of the disclosure as well, depending on relevant design factors, such as (but not limited to) performance impact, maintenance, chemical or material compatibility, electrical properties, flammability, environmental considerations, boiling points or other physical characteristics, safety considerations, etc.

[0041] In at least one embodiment, the particles 108 can be of uniform size and shape. In at least one embodiment, the particles 108 can be of differing sizes and / or shapes. In at least one embodiment, the particles 108 can be of uniform size and / or shape in one fluid path 106a and differing sizes and / or shapes in another fluid path 106b. In at least one embodiment, the particles 108 can be of still differing sizes and / or shapes in one or more other fluid paths 106c ...106n (collectively, fluid paths 106).

[0042] In at least one embodiment, the particles 108 can be of uniform mass and density. In at least one embodiment, the particles 108 can be of differing masses and / or densities. In at least one embodiment, the particles 108 can be of uniform mass and / or density in one fluid path 106a and differing masses and / or densities in another fluid path 106b. In at least one embodiment, the particles 108 can be of still differing masses and / or densities in one or more other fluid paths 106.

[0043] In at least one embodiment, the particles 108 can be shaped, sized and / or otherwise arranged for promoting or supporting turbulent flow through at least a portion of the cold plate 100 for increasing heat transfer from the cold plate 100 to the cooling fluid. In at least one embodiment, the particles 108 can be shaped, sized and / or otherwise arranged for avoiding dense packing of the particles 108 against one another, such as to minimize the chance of clogging or of overly restricting the flow path 106 through the cold plate 100 or a fluid path 106 thereof.

[0044] In at least one embodiment, the particles 108 can be configured to increase a transfer rate of heat from the walls 104 to a two-phase cooling fluid, such as relative to such an embodiment in the absence of the particles 108. In at least one embodiment, the particles 108 can be configured to fluidize when a cooling fluid is forced or otherwise moved through the fluid path 106, such as at (or above) a fluidization velocity. In at least one embodiment, the particles 108 can be configured to fluidize when a one-phase subcooled cooling fluid or a two-phase saturated cooling fluid is forced or otherwise moved through the fluid path 106 at a fluidization velocity. In at least one embodiment, thermally conductive particles 108 can be configured to transfer heat, such as through particle-wall collision and / or particle-particle collision. In at least one embodiment, the particles 108 can be configured to resist vapor insulation 138 of at least a portion of the walls 104 and / or one or more other surfaces of cold plate 100 during two-phase cooling of the cold plate 100. In at least one embodiment, the particles 108 can be configured to cause or increase turbulent flow in at least a portion of the fluid path 106.

[0045] In at least one embodiment, the cold plate 100 can have one or more fins 122 extending from the base 102. In at least one embodiment, one or more of the walls 104 can be a sidewall of the fin 122. In at least one embodiment, the cold plate 100 can have a plurality of fins 122 extending from the base 102, a plurality of fluid paths 106 through the cold plate 100, and aplurality of particles 108 or sets of particles 108 disposed within one or more of the fluid paths 106. In at least one embodiment, each of the plurality of fluid paths can have an inlet 112 and an outlet 114 and / or can be bounded on at least one side by a sidewall 104 of the cold plate 100, such as a sidewall 104 of one of the fins 122. In at least one embodiment, the particles 108 in a corresponding one of the fluid paths 106 can be confined fluidically between the inlet 1 12 and the outlet 1 14 of the fluid path 106, or fluidically between corresponding inlet and outlet filters 116, 118. In at least one embodiment, the cold plate 100 can have one or more fins 122 extending from the base 102 completely across the flow path 106, thereby dividing the flow path 106 into multiple flow paths (see, e.g., flow paths 106a, 106b, 106c). Such division can extend the entire length of the flow path 106 or along only a portion thereof. In at least one embodiment, the cold plate 100 can have one or more fins 122 extending from the base 102 partially across the flow path 106, thereby segmenting the flow path 106. Such segmentation can extend the entire length of the flow path 106 or along only a portion thereof.

[0046] In at least one embodiment, the cold plate can have an inlet manifold 140 in fluid communication with the inlet 112 of the fluid path 106, an outlet manifold 142 in fluid communication with the outlet 114 of the fluid path 106, an inlet filter 1 16 disposed fluidically downstream of the inlet manifold 140, an outlet filter 1 18 disposed fluidically upstream of the outlet manifold 142, or any combination thereof. In at least one embodiment, the particles 108 can be confined fluidically between the inlet filter 116 and the outlet filter 118. In at least one embodiment, each particle 108 can have a major dimension, the inlet filter 116 can have an inlet filter size, and the outlet filter 118 can have an outlet filter size. In at least one embodiment, the major dimension can be larger than the inlet filter size and / or the outlet filter size. In at least one embodiment, the inlet filter size and the outlet filter size can be different. In at least one embodiment, the inlet filter size and / or the outlet filter size can be configured to allow a cooling fluid to flow through the cold plate100 while the particles 108 are confined within the fluid path 106 fluidically between the inlet 112 and the outlet 114 and / or between the inlet filter 116 and the outlet filter 118.

[0047] In at least one embodiment, the cold plate 100 can have a first heat transfer rate when a cooling fluid is moved through the fluid path 106 at a first flow rate without the particles 108 disposed within the fluid path 106. In at least one embodiment, the cold plate 100 can have a second heat transfer rate when the cooling fluid is moved through the fluid path 106 at the first flow rate with the particles 108 disposed within the fluid path 106. In at least one embodiment, the second heat transfer rate can be greater than the first heat transfer rate. In at least one embodiment, the presence of the particles 108 disposed within the fluid path 106 contributes to the second heat transfer rate being greater than the first heat transfer rate. In at least one embodiment, the presence of the particles 108 disposed within the fluid path 106 can be responsible for the second heat transfer rate being greater than the first heat transfer rate, such as by improving heat transfer in one or more of the manners discussed herein.

[0048] In at least one embodiment, the cold plate 100 can have a first critical heat flux when a cooling fluid is moved through the fluid path 106 at a first flow rate without the particles 108 disposed within the fluid path 106. In at least one embodiment, the cold plate 100 can have a second critical heat flux when the cooling fluid is moved through the fluid path 106 at the first flow rate with the particles 108 disposed within the fluid path 106. In at least one embodiment, the second critical heat flux can be greater than the first critical heat flux. In at least one embodiment, the presence of the particles 108 disposed within the fluid path 106 contributes to the second critical heat flux being greater than the first critical heat flux. In at least one embodiment, the presence of the particles 108 disposed within the fluid path 106 can be responsible for the second critical heat flux being greater than the first criticalheat flux, such as by improving heat transfer in one or more of the manners discussed herein.

[0049] In at least one embodiment, the particles 108 can be configured to increase a transfer rate of heat from the walls 104 to a two-phase cooling fluid. In at least one embodiment, the particles 108 can be configured to fluidize when a two-phase cooling fluid is moved through the fluid path 106, such as at a velocity sufficient to fluidize the particles 108, which can be or include any velocity according to an implementation of the disclosure. In at least one embodiment, the fluid path 106 can be bounded by the base 102, one or more opposing walls 124, and one or more sidewalls 104. In at least one embodiment, heat can be transferred from the heat load 202 to the base 102, and to the opposing wall(s) 124 through or via the sidewalls 104 or fins 122. In at least one embodiment, the particles 108 can be configured to increase a transfer rate of heat to a two-phase cooling fluid from the base 102, the opposing wall 124, the sidewalls 104, or any combination thereof.

[0050] In at least one embodiment, a heat exchanger system 200 according to the disclosure can include one or more cold plates 100. In at least one embodiment, any or all of the cold plates 100 can include a base 102 configured to be disposed in thermal communication with a heat load 202, a plurality of fins 122 extending from the base 102, and a plurality of fluid paths 106 through the cold plate 100. In at least one embodiment, each of the fluid paths 106 can have an inlet 1 12 and an outlet 1 14, and a plurality of particles 108 disposed therein. In at least one embodiment, the system 200 can include one or more prime movers 206, such as a pump or compressor, for circulating a two-phase or other cooling fluid through the fluid paths 106 at a velocity for fluidizing each of the plurality of particle 108 sets, or any combination thereof. In at least one embodiment, each of the fluid paths 106 through the cold plate 100 can have a vertically oriented portion. In at least one embodiment, the particle 108 sets can be confined within the vertically oriented portions, suchas by filters 116, 1 18. In at least one embodiment, the fluidized particles 108 can resist vapor insulation 138 of one or more heat transfer surfaces during two-phase cooling of the one or more cold plates 100.

[0051] In at least one embodiment, a method according to the disclosure can include disposing a cold plate 100 in thermal communication with a heat load 202, moving a two-phase cooling fluid through a fluid path 106 of the cold plate 100, fluidizing a set of particles 108 disposed within the fluid path 106, or any combination thereof. In at least one embodiment, the method can include resisting clogging of the particles 108, such as by routing or holding some or all of the particles 108 in or to a tank or recycle path 130. In at least one embodiment, the method can include resisting vapor insulation 138 of one or more heat transfer surfaces by contacting the heat transfer surface(s) with one or more of the particles 108 during cooling operations. In at least one embodiment, the method can include utilizing one or more of the particles 108 and causing disruption of vapor formations and dry-out spots; disrupting plausible mechanisms governing critical heat flux for flow boiling; disrupting vapor blanket separation of a hot wall or other surface from bulk flow; disrupting dense bubble clusters adjacent to a hot surface; disrupting bubble coalescence near liquid sublayers near a hot surface; colliding with bubble formations on the surface of a wall, breaking them up and mixing them into the bulk fluid; re-wetting dry spots on a wall in the event of interfacial separation of a liquid surface and a hot wall, such as by breaking the surface tension of the vapor; colliding with a wall and conducting heat, thereby providing wall-to- particle conduction; colliding with other particles and conducting heat, thereby providing particle-to-particle conduction; boosting heat transfer area; providing nucleation sites to encourage boiling at lower temperatures; generally increasing turbulence; or any combination thereof. In at least one embodiment, the method can include routing the particles 108 away from one or more heat transfer surfaces or areas and cooling the particles 108.

[0052] In at least one embodiment, a cold plate for a heat exchanger system according to the disclosure can include a base configured to be disposed in thermal communication with a heat load, a first pair of walls extending from the base, a first fluid path through the cold plate, a plurality of particles disposed within the first fluid path, or any combination thereof. In at least one embodiment, the first fluid path can have an inlet and an outlet and / or be bounded on at least two sides by the first pair of walls. In at least one embodiment, the plurality of particles can be confined within the first fluid path fluidically between the inlet and the outlet. In at least one embodiment, the plurality of particles can be loosely disposed within the first fluid path. In at least one embodiment, the first fluid path can have a vertical portion, and the plurality of particles can be confined within the vertical portion.

[0053] In at least one embodiment, the plurality of particles can be thermally conductive particles. In at least one embodiment, the plurality of particles can include metal particles. In at least one embodiment, the plurality of particles can be configured to increase a transfer rate of heat from the first pair of walls to a two-phase cooling fluid. In at least one embodiment, the plurality of particles can be configured to fluidize when a two-phase cooling fluid is moved through the first fluid path. In at least one embodiment, the thermally conductive particles can be configured to transfer heat, such as through particle-wall collision and / or particle-particle collision. In at least one embodiment, the plurality of particles can be configured to resist vapor insulation of at least a portion of one or more of the first pair of walls during two-phase cooling of the cold plate. In at least one embodiment, the plurality of particles can be configured to cause or increase turbulent flow in at least a portion of the first fluid path.

[0054] In at least one embodiment, the cold plate can have a fin extending from the base. In at least one embodiment, one wall of the first pair of walls can be a sidewall of the fin. In at least one embodiment, the cold platecan have a plurality of fins extending from the base, a plurality of fluid paths through the cold plate, and a plurality of particles disposed within each of the plurality of fluid paths. In at least one embodiment, each of the plurality of fluid paths can have an inlet and an outlet and / or be bounded on at least one side by a sidewall of one of the plurality of fins. In at least one embodiment, the particles can be confined fl uidical ly between the inlet and the outlet of each of the plurality of fluid paths.

[0055] In at least one embodiment, the cold plate can have an inlet manifold in fluid communication with the inlet of the first fluid path, an outlet manifold in fluid communication with the outlet of the first fluid path, an inlet filter disposed fluidically downstream of the inlet manifold, an outlet filter disposed fluidically upstream of the outlet manifold, or any combination thereof. In at least one embodiment, the plurality of particles can be confined fluidically between the inlet filter and the outlet filter. In at least one embodiment, each particle of the plurality of particles can have a major dimension, the inlet filter can have an inlet filter size, and the outlet filter can have an outlet filter size. In at least one embodiment, the major dimension can be larger than the inlet filter size and / or the outlet filter size. In at least one embodiment, the inlet filter size and the outlet filter size can be different. In at least one embodiment, the inlet filter size and / or the outlet filter size can be configured to allow a cooling fluid to flow through the cold plate while the plurality of particles is confined within the first fluid path fluidically between the inlet and the outlet.

[0056] In at least one embodiment, the cold plate can have a first heat transfer rate when a first cooling fluid is moved through the first fluid path at a first flow rate without the plurality of particles disposed within the first fluid path. In at least one embodiment, the cold plate can have a second heat transfer rate when the first cooling fluid is moved through the first fluid path at the first flow rate with the plurality of particles disposed within the first fluid path. In atleast one embodiment, the second heat transfer rate can be greater than the first heat transfer rate.

[0057] In at least one embodiment, the cold plate can have a first critical heat flux when a first cooling fluid is moved through the first fluid path at a first flow rate without the plurality of particles disposed within the first fluid path. In at least one embodiment, the cold plate can have a second critical heat flux when the first cooling fluid is moved through the first fluid path at the first flow rate with the plurality of particles disposed within the first fluid path. In at least one embodiment, the second critical heat flux can be greater than the first critical heat flux. In at least one embodiment, the plurality of particles can be configured to increase a transfer rate of heat from the first pair of walls to a two-phase cooling fluid. In at least one embodiment, the plurality of particles can be configured to fluidize when a two-phase cooling fluid is moved through the first fluid path. In at least one embodiment, the plurality of particles can include metal particles.

[0058] In at least one embodiment, a heat exchanger according to the disclosure can include one or more cold plates. In at least one embodiment, any or all of the cold plates can include a base configured to be disposed in thermal communication with a heat load, a plurality of fins extending from the base, a plurality of fluid paths through the cold plate, with each of the plurality of fluid paths having an inlet and an outlet, a plurality of particle sets, wherein each of the plurality of particle sets is disposed within a corresponding one of the plurality of fluid paths, a prime mover configured to circulate a two-phase cooling fluid through the plurality of fluid paths at a velocity for fluidizing each of the plurality of particle sets, or any combination thereof. In at least one embodiment, each of the plurality of fluid paths through the cold plate can have a vertically oriented portion. In at least one embodiment, the particle sets can be confined within the vertically oriented portions by filters. In at least one embodiment, the fluidized particle sets can resist vapor insulation of one ormore heat transfer surfaces during two-phase cooling of the one or more cold plates. In at least one embodiment, a cooling method according to the disclosure can include disposing a cold plate in thermal communication with a heat load, moving a two-phase cooling fluid through a fluid path of the cold plate, fluidizing a particle set disposed within the fluid path, or any combination thereof.

[0059] Other and further embodiments utilizing one or more aspects of the disclosure can be devised without departing from the spirit of Applicant’s disclosure. For example, the devices, systems and methods can be implemented for numerous different types and sizes in numerous different industries. Further, the various methods and embodiments of the devices, systems and methods can be included in combination with each other to produce variations of the disclosed methods and embodiments. Discussion of singular elements can include plural elements and vice versa. The order of steps can occur in a variety of sequences unless otherwise specifically limited. The various steps described herein can be combined with other steps, interlineated with the stated steps, and / or split into multiple steps. Similarly, elements have been described functionally and can be embodied as separate components or can be combined into components having multiple functions.

[0060] The inventions have been described in the context of preferred and other embodiments and not every embodiment of the inventions has been described. Obvious modifications and alterations to the described embodiments are available to those of ordinary skill in the art having the benefits of the present disclosure. The disclosed and undisclosed embodiments are not intended to limit or restrict the scope or applicability of the inventions conceived of by the Applicant, but rather, in conformity with the patent laws, Applicant intends to fully protect all such modifications and improvements that come within the scope or range of equivalents of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A cold plate for a heat exchanger, the cold plate comprising: a base configured to be disposed in thermal communication with a heat load; a first pair of walls extending from the base; a first fluid path through the cold plate, the first fluid path having an inlet and an outlet and being bounded on at least two sides by the first pair of walls; and a plurality of particles disposed within the first fluid path; wherein the plurality of particles is confined within the first fluid path fluidically between the inlet and the outlet.

2. The cold plate of claim 1 , further comprising a fin extending from the base, wherein one wall of the first pair of walls is a sidewall of the fin.

3. The cold plate of claim 1 , further comprising a plurality of fins extending from the base, a plurality of fluid paths through the cold plate, each of the plurality of fluid paths having an inlet and an outlet and being bounded on at least one side by a sidewall of one of the plurality of fins; and a plurality of particles disposed within each of the plurality of fluid paths and confined fluidically between the inlet and the outlet thereof.

4. The cold plate of claim 1 , further comprising an inlet manifold in fluid communication with the inlet of the first fluid path; an outlet manifold in fluid communication with the outlet of the first fluid path; an inlet filter disposed fluidically downstream of the inlet manifold; andan outlet filter disposed fluidically upstream of the outlet manifold; wherein the plurality of particles is confined fluidically between the inlet filter and the outlet filter.

5. The cold plate of claim 4, wherein each particle of the plurality of particles has a major dimension, the inlet filter has an inlet filter size, and the outlet filter has an outlet filter size; and wherein the major dimension is larger than the inlet filter size and the outlet filter size.

6. The cold plate of claim 5, wherein the inlet filter size and the outlet filter size are different.

7. The cold plate of claim 5, wherein the inlet filter size and the outlet filter size are configured to allow a cooling fluid to flow through the cold plate while the plurality of particles is confined within the first fluid path fluidically between the inlet and the outlet.

8. The cold plate of claim 1 , wherein the plurality of particles is loosely disposed within the first fluid path.

9. The cold plate of claim 1 , wherein the first fluid path has a vertical portion, and wherein the plurality of particles is confined within the vertical portion.

10. The cold plate of claim 1 , wherein the plurality of particles comprises thermally conductive particles, and wherein the thermally conductive particles are configured to transfer heat via at least one of particle-wall collision, particle-particle collision, and a combination thereof.11 . The cold plate of claim 1 , wherein the plurality of particles is configured to resist vapor insulation of at least a portion of one or more of the first pair of walls during two-phase cooling of the cold plate.

12. The cold plate of claim 1 , wherein the plurality of particles is configured to cause or increase turbulent flow in at least a portion of the first fluid path.

13. The cold plate of claim 1 , wherein the cold plate has a first heat transfer rate when a first cooling fluid is moved through the first fluid path at a first flow rate without the plurality of particles disposed within the first fluid path; wherein the cold plate has a second heat transfer rate when the first cooling fluid is moved through the first fluid path at the first flow rate with the plurality of particles disposed within the first fluid path; and wherein the second heat transfer rate is greater than the first heat transfer rate.

14. The cold plate of claim 1 , wherein the cold plate has a first critical heat flux when a first cooling fluid is moved through the first fluid path at a first flow rate without the plurality of particles disposed within the first fluid path; wherein the cold plate has a second critical heat flux when the first cooling fluid is moved through the first fluid path at the first flow rate with the plurality of particles disposed within the first fluid path; and wherein the second critical heat flux is greater than the first critical heat flux.

15. The cold plate of claim 1 , wherein the plurality of particles is configured to increase a transfer rate of heat from the first pair of walls to a two-phase cooling fluid.

16. The cold plate of claim 1 , wherein the plurality of particles is configured to fluidize when a two-phase cooling fluid is moved through the first fluid path.

17. The cold plate of claim 1 , wherein the plurality of particles comprises metal particles.

18. A heat exchanger, comprising: one or more cold plates, wherein each of the one or more cold plates comprises a base configured to be disposed in thermal communication with a heat load; a plurality of fins extending from the base; and a plurality of fluid paths through the cold plate, each of the plurality of fluid paths having an inlet and an outlet; a plurality of particle sets, wherein each of the plurality of particle sets is disposed within a corresponding one of the plurality of fluid paths; and a prime mover configured to circulate a two-phase cooling fluid through the plurality of fluid paths at a velocity for fluidizing each of the plurality of particle sets.

19. The heat exchanger of claim 18, wherein each of the plurality of fluid paths through the cold plate has a vertically oriented portion, and wherein the particle sets are confined within the vertically oriented portions by filters.

20. The heat exchanger of claim 19, wherein the fluidized particle sets are configured to resist vapor insulation of one or more heat transfer surfaces during two-phase cooling of the one or more cold plates.

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