Area-enhanced cooling module and electronic assembly with microjet capture manifold

Abstract

A liquid cooling module and cooling assembly are disclosed that employ jet impingement to cool a heat-generating electronic device. The liquid cooling module includes a microjet capture manifold that is located on top of the base plate or integrated into the base plate of the liquid cooling module. The microjet capture manifold comprises an array of cavities aligned with jet nozzles that create a plurality microjets of pressurized coolant. The cavities serve both to confine high-shear turbulent flow and to increase the effective heat transfer surface area. As microjets of pressurized coolant are directed into the cavities, they absorb heat from the interior walls and carry the heat away from the heat source, resulting in improved thermal performance and cooling efficiency.

Description

[0001] Area-Enhanced Cooling Module and Electronic Assembly with Microjet Capture Manifold

[0002] Field of the Invention

[0003] The present invention relates generally to the field of liquid cooling systems for heat-generating electronic components used in high-performance computing (HPC), data centers, electric vehicles (EVs) and other electronic devices. More particularly, the present invention concerns jet impingement cooling modules and assemblies configured to provide direct liquid cooling (DLC) of heat-generating electronic components in high-performance computing (HPC), data centers, electric vehicles (EVs) and other electronic devices.

[0004] Related Art

[0005] High-performance computers, data centers and electric vehicles (EVs) rely on liquid cooling systems to manage the heat generated by their high-power electrical components. Liquid cooling systems for data centers, high-performance computing and electric vehicles (EVs) mainly come in one of two forms. The first form is air-assisted liquid systems, typically referred to as All-In-One ( or “AIO”) liquid cooling systems because each compute node has its own self-contained cooling system, rejecting heat to facility air. The second form is facility-level liquid cooling systems, where each compute node receives liquid coolant supplied by a central source in the facility. The central source is typically referred to as a coolant distribution unit (or “CDU’), which may be located either within a row, a rack or a larger system unit (several rows of racks).

[0006] In AIO liquid cooling systems, liquid coolant circulates through a cooling module that is in thermal communication with one or more heat-generating electronic components, such as a central processing unit (CPU), so that some of the heat absorbed from the heat-generating component(s) by the cooling module can be absorbed by the liquid coolant as the liquid coolant flows through the cooling module. After absorbing heat from the cooling module, the heated liquid coolant flows to a radiator, and fans in the server blow air across the radiator to cool the liquid coolant. Hence, the term “air-assisted liquid cooling.” Then the cooled liquid coolant is routed back through the cold plate to absorb more heat. This cycle may be repeated indefinitely while the compute node is in operation.

[0007] An alternative to air-assisted (AIO) liquid cooling is a technique called direct liquid cooling (DEC). In DEC cooling systems, the heat absorbed from heat generating components by the coolant is not rejected back to facility air and is instead aggregated into an elevated temperature coolant flow7that can be used to reject heat directly to ambient (via, for example, a building external dry- cooler) or communicate the heat to a facility level liquid cooling loop that rejects the collected heat to ambient using a chiller or diy cooler, the heat being communicated to this second loop using a cooling distribution unit (CDU).

[0008] With respect to facility-level cooling systems, CDUs are generally configured to supply liquid coolant fluid at a relatively low7flow7rate. But as the number and density of high intensity electronic heat sources used in computer nodes continues to grow and take up an increasing amount of space in computer processing equipment in order to satisfy growing power requirements, it is becoming increasingly difficult for a relatively low flow rate liquid coolant fluid source to efficiently remove a sufficient amount of heat from all the heatgenerating components that need to be cooled. In other words, the low flow rates of CDUs acts as a significant limitation on the performance of conventional DEC modules in facilitylevel cooling systems.

[0009] The performance of cooling modules in AIO and DLC systems is typically measured by the heat transfer coefficients of the coolant fluids used therein. The heat transfer coefficient is a measure of how effectively heat is transferred from the cooling surface to the liquid cooling fluid. Improving the heat transfer coefficient is largely considered the most effective way to improve facility-level cooling efficiency (whether in the context of airassisted liquid cooling (AIO), or direct liquid cooling (DLC)). This is because improving the heat transfer coefficient of the liquid coolant allows for the use of warmer liquid coolants to cool high-intensity heat sources. Using wanner liquid coolants to cool high-intensity heat sources in data centers can make energy-consuming chillers unnecessary7, and also may eliminate the need to use water to enhance the rejection of heat to the atmosphere. Furthermore, warmer liquid coolants can be useful for other processes not associated with cooling electronic heat sources, like heating (or keeping warm) rooms in bui ldings, heating water for bathing, cleaning or cooking, or heating pipes to prevent freezing in cold climates.

[0010] Two of the primary' approaches to implement liquid cooling (for AIO or DLC) cooling modules are (1) jet impingement cooling, and (2) micro-channel cooling. Cooling modules with jet impingement cooling cool heat sources by accelerating jets of liquid coolant toward a cooling surface that is in direct thermal communication (i.e., direct contact) with the heat source. The cooling surface may be a surface on the heat-generating component itself, or a surface on a thermally conductive cold plate (or “base plate) that is in direct contact with the heat-generating component. When the jets of liquid coolant strike and flow over the cooling surface, heat is transferred from the cooling surface directly into the liquid coolant fluid. The impinging jets destroy the formation of a thermal boundary' layer, produce turbulence, and provide very high heat transfer coefficients significantly exceeding 100,000 W / m2-K.

[0011] Cooling modules with micro-channels generate high effective heat transfer coefficients by forcing the liquid coolant to flow through a plurality of very' small channels that have a very / large amount of surface area relative to their overall footprint in the cooling modules. The micro-channels may be configured to increase the amount of surface area that comes into contact with the coolant fluid by as much as 10-15X. This technique of increasing the cooling performance of the cooling module is referred to as area enhancement. With this approach, effective heat transfer coefficients exceeding 100,000 W / m2-K may be generated, even while the local effective surface heat transfer coefficients also exceeding 100,000 W / 'm2-K may be generated even while the local surface heat transfer coefficients may only be on the order of 10,000 W / m2-K. Fins are also a w7ell-knowm area enhancement technique in the art. Adding fins on the base plate provide area enhancement by increasing the amount of exposed base plate surface area per unit planar area.

[0012] Relatively speaking, micro-channels have lower flow rate requirements compared to jet impingement. But the advantage of jet impingement is the possibility of achieving local heat transfer coefficients that are ten times greater the local heat transfer coefficients achieved with micro-channels.

[0013] As heat flux from the heat-generating devices (computer chips (CPU, GPU, NIC), power inverting chips, laser diodes, etc.) increase, there is a need to see further performance improvements in effective heat transfer coefficients while limiting flow rate and differential pressure across the cooling modules. Regardless of heat flux increases within the devices, improving effective heat transfer coefficients provides significant benefits for facility cooling efficiency, and is therefore a very important ongoing pursuit.

[0014] It would therefore be useful to have a cooling module capable of utilizing both jet impingement technology and area enhancement technology, as this combination offers the potential for significant additional performance improvements over both of the two cooling module technologies when used independently. The inventors of the present invention have recognized that combining the jet impingement advantage of higher local heat transfer coefficients with the advantages of a larger surface area (per unit planar area) can drastically reduce thermal resistances. Summary Of The Invention

[0015] Embodiments of the present invention provide a liquid cooling module that employs jet impingement to cool a heat-generating electronic device. The liquid cooling module includes a thermally conductive base plate that is in communication heat-generating electronic device (the heat source). Importantly, the base plate has structural features that enhance local convective heat transfer and suppress cross-jet interference by isolating microjet-induced turbulence and effluent. In particular, the base plate incorporates both (i) area enhancement geometries to increase effective surface area and local heat transfer coefficients, and (ii) confinement structures configured to capture and isolate turbulence and effluent generated by individual microjets. Confining the turbulence and the effluent prevents detrimental hydrodynamic interaction between adjacent jets, thereby preserving the integrity of each jet’s impingement flow field and enhancing overall thermal performance.

[0016] More specifically, the base plate includes an integrated microjet capture manifold comprising an array of cavities positioned to align with jet nozzles in a jet plate disposed within the module. Each cavity comprises an inlet or “mouth” region and interior sidewaHs dimensioned to receive and hydrodynamically contain the high-shear, turbulent core generated by an individual microjet or closely spaced jet group and to carefully manage the effluent from each individual microjet or closely spaced jet group. This targeted confinement maximizes localized convective heat transfer by minimizing lateral mixing and flow recirculation between adjacent jet structures. As pressurized coolant microjets emerge from the jet nozzles in the jet plate, each pressurized coolant microjet is directed into a corresponding cavity in the integrated microjet capture manifold. The cavities capture and confine the fluid energy of each microjet, isolating it from adjacent flow and preserving maximum conversion of fluid power to heat transfer performance. Additionally, as each pressurized microjet enters its corresponding cavity, the pressurized microjet and the induced flow within the cavity make direct contact with the interior sidewalls of the cavity, absorbing heat from the interior sidewalls. Thus, the cavities not only guide the flow and confine the turbulence associated with each microjet, but also significantly increase the effective surface area exposed to the coolant in the microjet, enhancing the overall heat transfer rate. As the microjets flow through and exit the microchannels, they carry / the absorbed thermal energy away from the base plate and out of the cooling module.

[0017] By combining jet impingement, surface area enhancement and targeted turbulence and effluent control, cooling modules constructed and used in accordance with embodiments of the present invention achieve superior cooling performance while requiring less fluid pressure than traditional jet-impingement systems. This design supports higher heat-dissipation rates and enables the use of warmer coolant temperatures — yielding improved overall energy efficiency and reduced operational and capital costs.

[0018] In one embodiment, the liquid cooling module includes a base plate thermally coupled on one side to a heat source and configured on the opposite side to receive cooling from a plurality of high-velocity liquid microjets. A jet plate, positioned between an inlet plenum and the base plate, includes a set of nozzles that receive pressurized coolant and accelerates the pressurized coolant and expels it an increased velocity to create microjets of pressurized coolant. The nozzles in the jet plate are configured to eject the microjets of pressurized coolant toward a microjet capture manifold integrated into the second side of the base plate.

[0019] The microjet capture manifold comprises a set of cavities, each having a mouth at its proximal end and interior sidewalls extending to a distal end. Each cavity is aligned with a corresponding nozzle or group of nozzles such that the microjets pass through the mouth, impinge on the interior walls, absorb heat, and exit the cavity. The geometry of the cavities is configured to isolate microjet flows and reduce hydrodynamic interaction between adjacent jets before, during, and after impingement, thereby enhancing local heat transfer and system cooling efficiency. Notably, the microjet capture manifold may be integrated into the base plate or simply thermally connected to the base plate (e.g. via thermal interface material).

[0020] In another embodiment, the liquid cooling module comprises a housing, a base plate, an inlet, an outlet connection, an array (or several array s) of nozzles that are either integrated into the housing of the cooling module or exist as part of a second plate (referred to as a “jet plate”) and fasteners that connect the housing to the base plate. A second set of fasteners may be used to fasten the cooling module to the heat source so that the base plate is in contact and thermal communication with the heat source. Some variations of the cooling module constructed according to the invention may use a tensioner to provide the downward force necessary’ to mount the base plate of the cooling module to the heat source. In this case, the fasteners are attached to the tensioner plate and the tensioner plate is in physical contact with the housing and / or base plate to transmit the downward force onto the heat source. The downward force is important because it ensures good thermal contact of the cooling module base plate with the underlying heat source. Thermal communication of the cooling module with the heat source may be improved by using a thermal interface material, which can take the form of thermal paste or a compressible foil. The housing may comprise one or more parts, forming an inlet plenum that is fed by the inlet. After the coolant passes through the inlet plenum, the coolant is accelerated through the nozzles located in the jet plate (or nozzles located within the housing). The nozzle-accelerated coolant is then directed towards the base plate for impingement. In yet another embodiment of the present invention, there is provided an electronic assembly that includes a cooling module and a heat source, wherein the microjet capture manifold is located on a cooling surface of the heat source, instead of being located on the base plate of the cooling module. In this embodiment, the electronic assembly comprises a heat source attached to a substrate, the heat source comprising a cooling surface attached to the heat source on a side opposite from the substrate. The assembly further comprises an inlet plenum, an inlet configured to admit, a liquid coolant into the inlet plenum, a housing, and a jet plate comprising a set of nozzles configured to receive pressurized coolant from the inlet plenum, accelerate the pressurized coolant to create a set of microjets, and expel the set of microjets at increased velocity to impinge on the cooling surface of the heat source. Suitably, the base plate of the cooling module may comprise an opening through which the microjets are directed to strike the cavities located on the cooling surface of the heat source.

[0021] The electronic assembly further comprises a microjet capture manifold, located on the cooling surface, comprising a set of cavities, each cavity having a proximal end, a distal end, an interior sidewall extending from the proximal end to the distal end, and a mouth disposed at the proximal end of the cavity. The proximal end of each cavity in the microjet capture manifold is aligned with a nozzle or group of nozzles in the jet plate so that all the microjets of pressurized coolant expelled from said aligned nozzle or group of nozzles will pass through the mouth in the proximal end of the cavity to contact and absorb heat from the interior sidewall of the cavity. The proximal ends, distal ends, mouths and interior sidewalls of all the cavities in the microjet capture manifold on the cooling surface are collectively configured to prevent or reduce interactions between microjet-induced flows of pressurized coolant before, during and after impingement on the cooling surface of the heat source. Unlike conventional cooling modules and cooling module assemblies, which lack geometric area-enhancement features on the base plate, embodiments of present invention provide the dual benefit of increasing heat transfer area exposed to the microjet (or set of microjets) and the turbulence created by its / their impingement, as well as protecting each microjet or subset of microjets from potentially detrimental interaction. The management requirements for the microjet effluent, together with the optimization of heat transfer enhanced area, makes the set of geometric features on the base plate uniquely suited to achieve the benefits sought.

[0022] By providing efficient area enhancement and reducing potentially detrimental interactions among jets (or sets of jets), embodiments of the present invention provide better performance per jet., thereby permitting a sparser distribution of jets to achieve a level of performance similar to a denser distribution of jets within the cooling module, or provide an equally dense distribution of jets with superior performance. The improved performance manifests itself in a reduction in needed flow rate or a further increase in the heat transfer coefficient such that higher coolant temperatures, higher heat fluxes, or both, can be achieved in the application of DEC using these cooling modules.

[0023] Brief Description of the Figures

[0024] The accompanying drawings, which are incorporated in and constitute part of the specification, illustrate preferred embodiments of the invention, and, together with the description, serve to explain the principles of the present invention. In the drawings, like reference numbers indicate identical or functionally similar elements. Additionally, unless otherwise indicated, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears. FIG. l is a perspective view of an exemplary cooling module attached to a heat source via a layer of thermal interface material (TIM), showing the main structural components and mounting hardware.

[0025] FIG. 2 is an exploded view of the cooling module of FIG. 1, further illustrating internal components including a housing seal that separates the inlet plenum from the microjet capture manifold.

[0026] FIG. 3 A is a top perspective view of a base plate having an integrated microjet capture manifold comprising multiple cavities.

[0027] FIG. 3B is an enlarged detail view of the region marked in FIG. 3A, showing the geometry of individual cavities and associated drainage ports and collection channels.

[0028] FIG. 4 i s a top view of the base plate of FIGS. 3A and 3B, illustrating the arrangement of cavity arrays, collection channels, and outlet plenums.

[0029] FIG. 5 is a perspective view7showing a jet plate aligned and attached to the base plate, with dow7el pins used for precise alignment.

[0030] FIG. 6 is a transparent view showing the alignment of jet plate nozzles with cavity mouths in the microjet capture manifold of the base plate.

[0031] FIG. 7 is a cross-sectional view7of another embodiment of a cooling module, illustrating internal fluid flow paths from inlet to outlet.

[0032] FIG. 8 is a similar view to FIG. 7 but without base plate sectioning, revealing a larger portion of the microjet capture manifold.

[0033] FIG. 9 show7s an alternative embodiment in which coolant exits the cavities by spilling out through the mouths of the cavities, facilitated by the use of stand-offs between the jet plate and base plate.

[0034] FIG. 11 illustrates a configuration in which multiple nozzles are aligned w7ith a single cavity, and the cavity has a drill-point-shaped distal end. FIG. 12 is a dimetric view showing cavities in the microjet capture manifold that are non-circular in shape.

[0035] FIG. 13 is an isometric top view of a recirculating cooling module with the top cap removed, showing a dual-stage jet impingement flow path.

[0036] FIG. 14 is a cross-sectional view of the cooling module of FIG. 13, identifying the first and second impingement zones.

[0037] FIG. 15 is another cross-sectional view of a cooling module similar to FIG. 14, illustrating internal coolant redirection through a secondary inlet plenum and second jet array.

[0038] FIG. 16 is a 34 cross-sectional view of the cooling module of FIGS. 13-15, providing structural detail of the internal layout.

[0039] FIG. 17 is a magnified view of the assembly shown in FIG. 16, illustrating the use of optional housing seals between key structural interfaces.

[0040] FIGS. 18A, 18B, and 18C show three configurations of corrugated features integrated into or thermally coupled to the microjet capture manifold to enhance jet isolation.

[0041] FIG. 19 is a3A cross-sectional view of a cooling module using the corrugated features of FIGS. 18A-18C, and showing a zig-zag nozzle arrangement to reduce jet interference.

[0042] FIG. 20 shows an alternate embodiment with a ring-shaped base plate and microjet capture manifold, circular cavity layout, and central fluid outlet.

[0043] FIG. 21 illustrates that cavity axis and jet impingement angles may be nonperpendicular relative to the base plate surface, enabling angled jet entry' and cavity orientation.

[0044] Detailed Description O f Exemplary Embodiments Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Notably, embodiments of the present invention may be implemented in a variety of different ways and for a variety of different industrial applications, as would be apparent to those of skill in the art after reading this disclosure, and the figures and examples described below are not meant to limit the scope of the present invention or its embodiments or equivalents.

[0045] Embodiments of the present invention dramatically improve the performance of cooling modules with base plates (or cold plates), whether or not the base plate is integrated with the heat generating component or simply thermally connected to it (e.g. via thermal interface material). The performance improvement over traditional base plate- equipped cooling modules largely stems from two characteristics of the invention. First, the invention incorporates a manifold on the impingement side of base plate, which has area enhancement geometries that expose additional surface area for contact with the impinging jets and improves the heat transfer rate per planar area. Second, the area enhancement geometries are also configured to assist in preventing detrimental interactions among jets within a jet array by physically separating jets or small subsets of jets, and by carefully managing the effluent from each jet or set of jets to ensure that all of the jets can impinge on the area enhancement geometries unimpeded by the effluent from other jets or sets of jets.

[0046] In general, embodiments of the present invention comprise an inlet, outlet, housing, base plate, housing to base plate fasteners and cooling module to heat source fasteners. Additional details about each of these parts and associated features are described above. The base plate is generally made of a thermally conductive material that can easily conduct heat. However, the invention works equally w'ell when the manifold features are integrated directly into the heat generating component. To enhance the overall heat transfer from the cooling module, the base plate in the present invention provides a surface area exposed to the coolant that is much greater than the planar area, where the planar area is measured in the same plane as the top face of the heat source intended to be cooled. To provide the benefit of reduced jet to jet (or set of jets to set of jets) interaction, these increases in area are obtained by surrounding (or partially surrounding) the jet or set of jets and only providing a small but meaningful orifice (or drainage port) for the impinged coolant to escape. A feature of the base plate is a microjet capture manifold integral with the base plate. The microjet capture manifold has cavities with apertures configured to be aligned with a nozzle or group of nozzles in the jet plate such that the fluid accelerated by a nozzle or group of nozzles dissipates the bulk of its energy within the cavity before exiting the cavity. An example of the diametric size of such a cavity is approximately 0.3 mm to 2 mm. The interior sidewalls of the cavities can be, but do not have to be, vertical or cylindrical. In other words, the interior sidewalls of the cavities may be angled (relative to the plane of the surface of the heat source), rectangular, asymmetrical, conical or any other suitable shape.

[0047] Effective deployment of embodiments of the invention may include careful management of the effluents from the cavities. The effluent from all cavities is efficiently discharged from the cavities into collection channels that allow the coolant to be transported away from the base plate so that the effluent does not interact or interfere with the impingement of other microjets or sets of microjets impinging on the base plate.

[0048] Based on the features of the microjet capture manifold in the base plate, as described above, consisting of cavities with drainage ports that direct effluent into the collection channels, a useful optional feature of the invention is an alignment pin that dimensionally ties the relative position of the nozzles within the cooling module to the position of the cavities within microjet capture manifold on the base plate. While other means of dimensional control can be used to align the nozzles of the jet plate with the proximal ends of the cavities in the microjet capture manifold, the inventors of the present invention have observed that the alignment pin is a particularly mechanically effective solution for achieving the required alignments. A further optional alignment feature is profiling a receiving boss in the base plate geometry / to receive a matching opening in the jet plate surface.

[0049] Further optional features in the present invention include seals that prevent leakage between the inlet manifold and the outlet manifold.

[0050] Another manner in which the relative position between the jets and the base plate features can be controlled is by building the jet nozzles into the base plate using additive manufacturing, or by building the jet plate from a material that is able to be brazed, welded, or otherwise permanently affixed to the base plate where an additional performance advantage is generated due to the thermal connection that is made using these techniques between the jet. plate and the base plate, allowing heat form the base plate to be conducted into the jet plate.

[0051] In some embodiments, the microjet capture manifold on the base plate may comprise one or more corrugated strips configured to define features of the cavities. In this situation, the one or more corrugated strips may be affixed to the impingement side of the base plate, for example, by soldering, brazing, wielding or other suitable operation that affixes the corrugation strip(s) to the impingement side of base plate so that heat can flow from the base plate into the one or more corrugations.

[0052] A further optional feature in the implementation of the present invention is to implement cavities that are angled so that the major axis of each cavity is not perpendicular to the plane of the top surface of the heat source. The nozzles of the jet plate may be aligned with the major axes of the cavities, but the nozzles also may exist at some other angle relative to the plane formed by the top surface of the heat source. Such non-perpendicular implementations of the major axes of the cavities in the microjet capture manifold may further increase the total surface area exposed to the microjets within a given vertical envelope (where vertical is measured along the dimension perpendicular to the heat source plane). Misalignment between the major axes of the cavities and the major axes of the nozzles aids in generating greater turbulence and improving the total heat transfer rate provided by the cavities of the microjet-capture manifold.

[0053] FIG. 1 show's a cooling module 100 constructed according to one exemplary' embodiment of the present invention, wherein the cooling module 100 is attached to a heat source 190 via a layer of thermal interface material (TIM) 185. As shown in FIG. 1, the cooling module 100 typically comprises a base plate 105, a jet plate 110, an inlet 115, an outlet 120, and a housing 125 - which may (or may not) comprise multiple components, as illustrated in FIG. 1. The TIM 185 is typically compressed using downward force exerted on the cooling module 100 by a tensioner plate 130. Specifically, the tensioner plate 130, a set of screws 132a - 132c, a set of springs 134a - 134c, and a set of receiving nuts 170a - 170c attached to the substrate 180 are configured to engage with each other and cooperate to removably fix the cooling module 100 to a substrate 180 so that the underside of the base plate 105 is forced downward to make solid contact with the TIM 185, which is in thermal communication with the heat source 190. .Another set of fasteners, comprising a second set of screw's 136a - 136c and a corresponding second set of nuts 138a - 138c are provided to fasten the components of the cooling module 100 together.

[0054] The upward-facing side of the base plate 105, opposite the side in thermal contact with the TIM 185 and heat source 190, includes an integral microjet capture manifold 140. This manifold 140 comprises multiple cavities 145 that extend upward toward the nozzles in the jet plate 110. Each cavity has a proximal end with a mouth (or orifice) that is precisely aligned with a corresponding nozzle or group of nozzles in the jet plate 110. When pressurized coolant is expelled from the nozzles, each resulting microjet passes through the aligned mouth into its designated cavity. As the microjet flows through the cavity, it makes contact with the interior sidewalls, absorbing heat before exiting the cavity.

[0055] FIG. 2 shows the same cooling module of FIG. 1 in exploded view with relevant components identified with reference numbers identical to the reference numbers used in FIG. 1. However, FIG. 2 also shows the relative location of a housing seal 160, located above the jet plate 110. The housing seal 160 ensures that the pressurized coolant, delivered to the inlet plenum 155 through the inlet 115, cannot bypass the jet plate 110 and flow directly into the microjet capture manifold 140. Instead, the coolant is forced to pass through the nozzles in the jet plate 110 before reaching the microjet capture manifold 140." FIGs. 3A and 3B show detailed views of the base plate 305, which includes the microjet capture manifold 310 located on the impingement side of the baseplate 305. FIG. 3A is a top perspective view of the entire base plate 305. FIG. 3B is an inset showing a magnified view of the region in FIG. 3 A that is marked with a box and the pointer D. As shown in FIGs. 3 A and 3B, the microjet capture manifold 310 on the surface of base plate 305 comprises a set of cavities 315 configured to capture microjets (not shown) created and ejected by the nozzles of the jet plate 110 (shown in FIGs. I and 2). The set of cavities maybe evenly spaced and arranged into one or more arrays across the microjet capture manifold 310, or they may be arranged randomly across the microjet capture manifold 310. Each cavity 315 in the microjet-capture manifold 310 includes a proximal end 320 with a mouth 335, a distal end 325, and an interior sidewall 330 extending between them.

[0056] In the example embodiment shown in FIGs. 3 A and 3B, each cavity 315 also includes a drainage port 340 that is in fluid communication with a collection channel 345, which carries microjet effluent from all the cavities 315 to one or more outlet plenums 350 located at one or both ends of the microjet capture manifold 310. Also shown in FIGs. 3 A and 3B are a set of alignment pin holes 355 that can be used to align the jet plate 110 with the microjet capture manifold 310 so that the nozzles in the jet plate 110 will be in alignment with the cavities 315 in the microjet capture manifold 310.

[0057] FIG. 4 shows in top view the same exemplary base plate 405 shown in FIGs. 3 A and 3B. As can be seen in FIG. 4, the base plate 405 includes an integrated microjet capture manifold 410 comprising multiple sets (arrays) 415 of cavities 420 that are intersected by multiple collection channels 425, respectively, to define a multiplicity of drainage ports. Each one of the collection channels is fluidly connected to one or more outlet plenums 430 in the microjet capture manifold 410 so that microjet effluent discharged from the cavities 415 into the collection channels 425 wall be transported to the outlet plenums 430. In the exemplary embodiment of the base plate 405 shown in FIG. 4, for example, the microjet capture manifold 410 has eighteen different cavity arrays 415, comprising a total of three-hundred six cavities 420, each cavity 420 having a single discharge port fluidly- connecting each cavity 420 to one of nine different collection channels 425 that can transport the microjet effluent discharged from the cavities 420 to one or both of two different outlet plenums 430. However, those skilled in the art will recognize and appreciate that the microjet capture manifold 410 in the base plate 405 may comprise any suitable number of cavities, arrays of cavities, discharge ports in the cavities, collection channels and outlet plenums without departing from the scope of claimed invention.

[0058] FIG. 5 shows by way of example a jet plate 510 attached to and aligned with the top surface of a base plate 505, the top service of the base plate 505 having an integrated microjet capture manifold 515. In this example, dowel pins 520 are inserted through dowel pin holes in the jet plate 510 and the base plate 505 so that the mouths of the cavities (not shown in FIG. 5) in the microjet capture manifold 515 beneath the jet plate 510 will be aligned with nozzles 525 in the jet plate 510. The fluid outlet area plenums 530 are more evident with the jet plate 510 in place. FIG. 6 shows another illustration of the components of a base piate 605 constructed in accordance with certain embodiments of the present invention. FIG. 6 was generated by making the jet plate transparent, which allows the alignment between the mouths of the cavities 610 in the microjet capture manifold 615 of the base plate 605 and the nozzles 620 in the jet plate to be more easily observed and comprehended. FIG. 6 also shows, by way of example, the presence of multiple collection channels 625 and outlet plenums 630.

[0059] FIG. 7 shows another view of a cooling module 700 constructed according to an embodiment of the present invention. As shown in FIG. 7, the cooling module 700 comprises a base plate 705, a microjet capture manifold 710 embedded in the top surface of the base plate 705, a jet plate 715, and a housing 720. A housing seal 725 prevents flow from the inlet plenum 730, located above the jet plate 715 and supplied with pressurized coolant by the inlet 732, to the cavities 734 in the microjet capture manifold 710 without the liquid coolant passing through the nozzles 735 in the jet plate 715. FIG. 7 also show's how the outlet plenum 740 of the microjet capture manifold 710 of the base plate 705 is fluidly connected to an outlet 745 on the housing 720, allowing the coolant (not shown) to be removed from the cooling module 700. The arrows in FIG . 7 show the direction of flow for the liquid coolant at various points inside the cooling module 700.

[0060] FIG. 8 is identical to FIG. 7, except the base plate 705 is not sectioned and a larger portion of the microjet capture manifold 710 is visible. FIG. 8 also shows the dowel alignment hole 750 in the base plate 705.

[0061] FIG. 9 show's an alternative arrangement of cavities 905 in the microjet capture manifold 910, a corresponding alternative arrangement of nozzles 915 in the jet plate 920, and an alternative means of egress for the liquid coolant (post impingement). For this alternative arrangement, the components of the microjet capture manifold 910 are suitably arranged so that, after filling up the cavities 905, the impingement fluid (not shown) is allowed to exit the cavities 905, not by passing through drainage ports in the sidewalls of the cavities 905, but by spilling out of the mouths of the cavities 905. To facilitate this process, a vertical clearance between the nozzles 915 of the jet plate 920 and the mouths of the cavities 905 in the microjet capture manifold 910 is achieved by the insertion of a plurality of standoffs 925 between the jet plate 920 and the microjet capture manifold 910 of the base plate 930, allowing the impingement coolant to exit the cavities 905 through the mouths of the cavities 905 and spill into the collection channels 935.

[0062] FIG. 10 shows the a close-up of the stand-off feature between the jet. plate and microjet capture manifold that allows the coolant to escape. All components were previously identified in FIG. 9.

[0063] FIG. 11 shows the an alternate configuration of the nozzles 1105 in the jet. plate 1 110 and the cavities 1115 in the microjet capture manifold, demonstrating an embodiment of the present invention in which multiple nozzles 1105 in the jet plate 1110 are aligned with each cavity 1115 in the microjet capture manifold 1120 of the base plate 1130 . FIG. 11 also illustrates the use of a wider stand-off 1135 between the jet plate 1 1 10 and the mouths 11 17 of the cavities 1115. FIG. 11 further illustrates that the distal ends 1150 of each cavity 1115 may have a drill point shape. The shape of the distal ends 1150 of the cavities 1115 is not central to the invention, but the drill point shape shown in FIG. 11 may be a convenient result from a chosen manufacturing process.

[0064] FIG. 12, which shows a dimetric view of the cooling module illustrates that, the cavities 1205 in the microjet capture manifold 1210 do not necessarily have to be circular and can be of arbitrary' shape.

[0065] FIG. 13 shows an isometric view from the top of a recirculation cooling module 1300 (with cap removed) in which the fluid (not shown) impinges twice in series. The inlet 1305 feeds a first jet array section 1310. The collection channels below first jet array section 1310 gather the effluent into an outlet plenum 1315, which is in fluid communication with a second jet array 1320. Collection channels below the second jet array 1320 gather the effluent into the outlet plenum 1330 before allowing the coolant to exit via the outlet 1335.

[0066] FIG. 14 show's a cross-sectioned view of the recirculation cooling module 1300 shown in FIG. 13. As shown in FIG. 14, the first impingement zone 1405 is located substantially in the middle of the cooling module 1300, and the second impingement zone 1410 is located closer to the perimeter of the cooling module 1300.

[0067] FIG. 15 shows another cross-sectional view of a cooling module 1500, which is identical in construction to the cooling modules 1300 shown in FIGs. 13 and 14. However, FIG. 15 is provided to illustrate that the collection channels 1510 in the first impingement zone of cooling module 1500 do not lead directly to the outlet 1535 of the cooling module 1500. Instead, the collection channels 1510 transport liquid coolant to a secondary' inlet plenum 1515, where the liquid coolant is then forced to pass through a second set of nozzles 1520 located closer to the perimeter of the cooling module 1500.

[0068] FIG. 16 show's a % cross-sectional view of the cooling modules 1300 and 1500 show'll in FIGs. 13, 14 and 15 in order to provide additional visual detail concerning the overall construction of this exemplary' embodiment of the present invention.

[0069] FIG. 17 is a magnified view of a section of the cooling module shown in FIG. 16, which illustrates the optional deployment of housing seals 1705 interposed between the microjet capture plate 1710 of the base plate 1720 and the jet plate 1725, or between the housing 1735 and the jet plate 1725.

[0070] FIGs. 18 A, 18B and I 8C show three different approaches to providing cavities that protect adjacent microjets according to some embodiments of the present invention. As shown in FIGs. 18 A, 18B and 18C, corrugations 1805 may be added to the microjet capture manifold 1810 of the base plate 1815. Such corrugations 1805 may be integrated into the microjet capture manifold 1810, the base plate 1815, or both, or manufactured separately and then put in thermal contact with the microjet capture manifold 1810, the base plate 1815, or both, via brazing, welding or similar process.

[0071] FIG. 19 show's a % cross-sectional view of a cooling module 1900 utilizing the corrugations 1905 shown in FIGs. 18A, 18B and 18C. Beneficially, the corrugations 1905 in the microjet capture manifold 1910 of the base plate 1920 allow the nozzles 1935 in the jet plate 1930 to have a zig-zag patern, which can contribute to reducing or preventing significant microjet-to-microjet interaction in the microjet capture manifold 1905 of the base plate 1920.

[0072] FIG. 20 shows an alternate configuration of the base plate 2005 and microjet capture manifold 2010 in certain embodiments of the present invention. These embodiments use circular collection channels 2015 instead of linear collection channels, and a generally ring-shaped microjet capture manifold 2010, located on the impingement side of a generally circular base plate 2005, and a generally circular jet plate 2025. The microjet capture manifold 2010 of the base plate 2005 has cavities 2022 that communicate with the collection channels 2015 to route the fluid to a central outlet 2035.

[0073] FIG. 21 show's that the alignment between the bottom surface of base plate 2105 (in plane with heat source’s top surface) and the cavities 2110 in the microjet. capture manifold can be implemented as non-perpendicular components, with the axis 2115 of the cavity 21 10 not being aligned with the base plate bottom surface normal N. Similarly, the impingement nozzle direction D provided by the jet plate 2120 may not be aligned with either the base plate bottom surface normal N or the cavity axis 2115. These angles are designated (A) and (B) in the section view'. Skilled artisans will recognize that it is possible to design a staged impingement cooling module where, without having the fluid exit the cooling module, internal routing and manifolding is used to supply the jet impingement arrays with coolant based on successive sections in the array (as shown in FIG. 21). The above-described preferred embodiments are intended to illustrate the principles of the invention, but not to limit its scope. Various other embodiments, modifications and equivalents to these preferred embodiments may occur to those skilled in the art. upon reading the present disclosure or practicing the claimed invention. Such variations, modifications and equivalents are intended to come within the scope of the invention and the appended claims.

Claims

What is claimed is:I . A cooling module for cooling of a heat source on a substrate, comprising:(a) a base plate having a first side that is in thermal communication with the heat source and a second side that is opposite from first side and the heat source;(b) an inlet plenum;(c) an inlet configured to admit a liquid coolant into the inlet plenum;(d) a housing;(e) a jet plate disposed between the inlet plenum and the base plate, the jet plate comprising a set of nozzles configured to receive pressurized coolant from the inlet plenum, accelerate the pressurized coolant to create a set of microjets, and expel the set of microjets at increased velocity to impinge on the second side of the base plate; and(f) a microjet capture manifold, located on the second side of the base plate, the microjet capture manifold comprising a set of cavities, each cavity having a proximal end, a distal end, an interior sidewall extending from the proximal end to the distal end, and a mouth disposed at the proximal end of the cavity;(g) wherein(i) the proximal end of each cavity in the microjet capture manifold is aligned with a nozzle or group of nozzles in the jet plate so that all the microjets of pressurized coolant expelled from said aligned nozzle or group of nozzles will pass through the mouth in the proximal end of said each cavity to contact and absorb heat from the interior sidewall of said cavity, and(ii) the proximal ends, distal ends, mouths and interior sidewalls of all the cavities in the microjet capture manifold are configured to prevent or reduce interactions between microjet- induced fl ows of pressurized coolant before, during and after impingement on the base plate.

2. The cooling module of claim 1, wherein each cavity in the microjet capture manifold further comprises a drainage port, located in the interior sidewall, the proximal end or the distal end of the cavity, the drainage port configured to discharge effluent from the microjets of pressurized coolant after the microjets of pressurized coolant has absorbed heat from the interior sidewall of the cavity.

3. The cooling module of claim 2, wherein the microjet capture manifold further comprises:(a) an outlet plenum configured to store effluent discharged from the drainage port of each cavity in the microjet capture manifold; and(b) a collection channel configured to receive effluent discharged from the drainage port and cany the effluent to the outlet plenum.

4. The cooling module of claim 3, wherein the cooling module further comprises an outlet, attached to the housing and in fluid communication with the outlet plenum, the outlet configured to permit the effluent stored in the outlet plenum to pass out of the cooling module.

5. The cooling module of claim 3, wherein the microjet capture manifold further comprises:(a) a standoff interposed between the jet plate and the proximal ends of the cavities in the set of cavities;(b) wherein the standoff is configured to provide sufficient spacing between the nozzles in the jet plate and the proximal ends of the cavities to permit effluent from the microjets of pressurized liquid coolant to spill out of the mouths of the cavities and flow into the collection channel.

6. The cooling module of claim 3, wherein the cavities, outlet plenum and collection channel in the microjet capture manifold are collectively configured to isolate and confine turbulent flows of pressurized liquid coolant so that, turbulent flows induced by microjets created by one nozzle or group of nozzles do not interact with turbulent flows induced by microjets created by nearby nozzles or groups of nozzles, respectively.

7. The cooling module of claim 1, further comprising a seal interposed between the jet plate and a section of the housing to prevent pressurized liquid coolant fluid from flowing out of the inlet plenum without passing through the nozzles in the set of nozzles in the jet plate.

8. The cooling module of claim 1, further comprising a first fastener for attaching the housing to the base plate.

9. The cooling module of claim 1, further comprising a second fastener for attaching the cooling module to the heat source.

10. The cooling module of claim 1, further comprising a tensioner plate and a set of screw's configured to cooperatively exert downward pressure on the cooling module to removably fasten the cooling module to the substrate.

11. The cooling module of claim 1, wherein the interior sidewall of some of the cavities in the set of cavities further comprise a set of grooves, or a set of micro fins or a set of pin fins configured to increase an amount of surface area that, will be struck by the microjets of pressurized liquid coolant fluid propelled by the nozzles of the jet plate.

12. The cooling module of claim 1 , wherein the jet plate is an integral component of the housing,13. The cooling module of claim 1, wherein the housing and the jet plate are manufactured as a unitary component.

14. The cooling module of claim 1, wherein the jet plate is an integral component of the base plate.

15. The cooling module of claim 1, wherein the jet plate is manufactured as an integral component of the base plate by additive manufacturing technology.16, The cooling module of claim 1, wherein the jet plate is permanently affixed to the second side of the base plate.

17. The cooling module of claim 1, wherein:(a) the set of nozzles in the jet plate and the set of cavities on the second side the base plate are arranged such that two or more nozzles in the set of nozzles in the jet plate are aligned with the mouth of a single cavity in the set of cavities; and(b) the microjets of pressurized liquid coolant fluid propelled from said two or more nozzles will pass through the mouth of said single cavity and strike the interior sidewall of said single cavity, the distal end of said single cavity, or both.

18. The cooling module of claim 1, wherein the distal ends of at least some of the cavities in the set of cavities have an inverted conical shape.

19. The cooling module of claim 1, wherein at least some of the cavities in the set of cavities are cylindrical .

20. The cooling module of claim 1, wherein at least some of the cavities in the set of cavities are rectangular.

21. The cooling module of claim 1, wherein at least some of the cavities in the set of cavities have interior sidewalls that are asymmetrical.

22. The cooling module of claim 1, further comprising an alignment pinhole in the jet plate to facilitate aligning nozzles in the jet plate with the mouths of cavities in the set of cavities in the microjet capture manifold on the second side of the base plate.

23. The cooling module of claim 1, wherein a thermal interface material is interposed between the first side of the base plate and the heat source to improve thermal communication between the first side of the base plate and the heat source.

24. The cooling module of claim 1, further comprising:(a) a second inlet plenum and a second jet plate;(b) the second jet plate including a second set of nozzles extending through the second jet plate, each nozzle configured to accept pressurized coolant fluid from the second inlet plenum, accelerate the pressurized coolant fluid to create a second set of microjets of pressurized coolant, and propel the second set of microjets at increased velocity toward the second surface of the base plate; and(c) a second microjet capture manifold located on the second surface of the base plate, the second microjet capture manifold comprising a second set of cavities, each cavity in the second plurality having a proximal end, a distal end, a mouth in the proximal end, and an interior sidewall extending from the proximal end of the cavity to the distal end of the cavity;(d) wherein(i) each nozzle in the second set of nozzles is aligned with the mouth of a cavity in the second set of cavities so that the microjets of pressurized coolant created by said aligned nozzle will pass into and through the mouth of said cavity to contact and absorb heat from the interior sidewall of said cavity, and(ii) the proximal end, distal end, mouth and interior sidewall of said cavity are collectively configured to reduce or prevent the microjets of pressurized liquid coolant expelled by one nozzle or group of nozzles from interacting with the microjets of pressurized coolant expelled by a nearby nozzle or group of nozzles, respectively.25, The cooling module of claim 24, wherein the second microjet capture manifold further comprises a second collection channel running alongside or beneath the second set of cavities and configured to receive pressurized coolant expelled from the cavities in the second set of cavities, and route the pressurized liquid coolant fluid to the second inlet plenum.

26. The cooling module of claim 25, further comprising:(a) a second outlet plenum, in fluid communication with the second collection channel, configured to store pressurized liquid coolant fluid from the second collection channel; and(b) an outlet, attached to the housing and in fluid communication with the second outlet plenum, the outlet configured to permit the pressurized liquid coolant fluid stored in the second outlet plenum to flow out of the cooling module.

27. The cooling module of claim 26, wherein the second microjet capture manifold further comprises a second set of drainage ports in the interior sidewalls of the second set of cavities or the distal ends of the second set of cavities, the second set of drainage ports being configured to discharge pressurized liquid coolant fluid into the second collection channel.

28. The cooling module of claim 26, wherein the second microjet capture manifold further comprises:(a) a second standoff interposed between the second jet plate and second set of cavities;(b) wherein the second standoff is configured to provide sufficient spacing between the nozzles in the second jet plate and the second set of cavities to allow pressurized coolant fluid inside the cavities of the second set of cavities to spill out of the mouths of the cavities and flow into the second collection channel.

29. The cooling module of claim 24, wherein the mouths, interior sidewalls and distal ends of the cavities in the second set of cavities are configured to isolate and confine turbulent flows of pressurized liquid coolant fluid induced by the microjets of pressurized liquid coolant fluid striking the interior walls of the cavities, the distal ends of cavities, or both, so that turbulent flows induced by microjets expelled from one nozzle in the second set of nozzles do not interact with turbulent flows induced by microjets expelled by another nozzle in the second set of nozzles.

30. The cooling module of claim 24, further comprising a second seal interposed between the second jet plate and a second section of the housing to prevent pressurized liquid coolant fluid from bypassing the second jet plate and flowing directly into the second microjet capture manifold.

31. The cooling module of claim 24, wherein:(a) the second set of nozzles in the second jet plate and the second set. of cavities on the first surface of the base plate are arranged such that two or more nozzles in the second set of nozzles in the second jet plate are aligned with the mouth of a single cavity in the second set. of cavities; and(b) the microjets of pressurized coolant fluid expelled from said two or more nozzles in the second set of nozzles will pass through the mouth of said single cavity in the second set of cavities and strike the interior sidewall of said single cavity, the distal end of said single cavity, or both.

32. The cooling module of claim 24, wherein the distal ends of at least some of the cavities in the second set of cavities have an inverted conical shape.

33. The cooling module of claim 24, wherein at least some of the cavities in the second set of cavities are cylindrical.

34. The cooling module of claim 24, wherein at least some of the cavities in the second set of cavities are rectangular.

35. The cooling module of claim 24, wherein at least some of the cavities in the second set of cavities have interior sidewalls that are asymmetrical.

36. The cooling module of claim 24, further comprising a second alignment pinhole in the second jet plate to facilitate aligning nozzles in the second jet plate with the mouths of cavities in the second set of cavities on the microjet capture manifold on the second surface of the base plate.

37. An electronic assembly, comprising:(a) a heat source attached to a substrate, the heat source comprising a cooling surface attached to the heat source on a side opposite from the substrate;(b) an inlet pl enum ;(c) an inlet configured to admit a liquid coolant into the inlet plenum;(d) a housing;(e) a jet plate comprising a set of nozzles configured to receive pressurized coolant from the inlet plenum, accelerate the pressurized coolant to create a set of microjets, and expel the set of microjets at increased velocity to impinge on the cooling surface of the heat source; and(f) a microjet capture manifold, located on the cooling surface, the microjet capture manifold comprising a set of cavities, each cavity having a proximal end, a distal end, an interior sidewall extending from the proximal end to the distal end, and a mouth disposed at the proximal end of the cavity;(g) wherein(i) the proximal end of each cavity in the microjet capture manifold is aligned with a nozzle or group of nozzles in the jet plate so that all the microjets of pressurized coolant expelled from said aligned nozzle or group of nozzles will pass through the mouth in the proximal end of said each cavity to contact and absorb heat from the interior sidewall of said cavity, and(ii) the proximal ends, distal ends, mouths and interior sidewalls of all the cavities in the microjet capture manifold are configured to prevent or reduce interactions between microjet- induced flows of pressurized coolant before, during and after impingement on the cooling surface of the heat source.

38. The electronic assembly of claim 37, wherein each cavity in the microjet capture manifold further comprises a drainage port, located in the interior sidewall, the proximal end or the distal end of the cavity, the drainage port configured to discharge effluent from the microj ets of pressurized coolant after the microjets of pressurized coolant has absorbed heat from the interior sidewall of the cavity.

39. The electronic assembly of claim 38, wherein the microjet capture manifold further comprises:(a) an outlet plenum configured to store effluent discharged from the drainage port of each cavity' in the microjet capture manifold; and(b) a collection channel configured to receive effluent discharged from the drainage port and carry the effluent to the outlet plenum.

40. The electronic assembly of claim 39, wherein the cooling module further comprises an outlet, attached to the housing and in fluid communication with the outlet plenum, the outlet configured to permit the effluent stored in the outlet plenum to pass out of the cooling module.41 . The electronic assembly of claim 37, wherein the microjet capture manifold further comprises:(a) a standoff interposed between the jet plate and the proximal ends of the cavities in the set of cavities,(b) wherein the standoff is configured to provide sufficient spacing between the nozzles in the jet plate and the proximal ends of the cavities to permit effluent from the microjets of pressurized liquid coolant to spill out of the mouths of the cavities and flow into the collection channel.

42. The electronic assembly of claim 39, wherein the cavities, outlet plenum and collection channel in the microjet capture manifold are collectively configured to isolate and confine turbulent flow's of pressurized liquid coolant so that turbulent flows induced by microjets created by one nozzle or group of nozzles do not interact with turbulent flows induced by microjets created by nearby nozzles or groups of nozzles, respectively.

43. The electronic assembly of claim 37, further comprising:(a) a second inlet plenum and a second jet plate;(b) the second jet plate including a second set of nozzles extending through the second jet plate, each nozzle configured to accept pressurized coolant fluid from the second inlet plenum,accelerate the pressurized coolant fluid to create a second set of microjets of pressurized coolant, and eject, the second set of microjets at increased velocity toward the second surface of the base plate; and(c) a second microjet capture manifold located on the cooling surface of the heat source, the second microjet capture manifold comprising a second set of cavities, each cavity in the second plurality having a proximal end, a distal end, a mouth in the proximal end, and an interior sidewall extending from the proximal end of the cavity to the distal end of the cavity;(d) wherein(i) each nozzle in the second set of nozzles is aligned with the mouth of a cavity in the second set of cavities so that the microjets of pressurized coolant created by said aligned nozzle wall pass into and through the mouth of said cavity to contact and absorb heat from the interior sidewall of said cavity, and(ii) the proximal end, distal end, mouth and interior sidewall of said cavity are collectively configured to reduce or prevent the microjets of pressurized liquid coolant expelled by one nozzle or group of nozzles from interacting with the microjets of pressurized coolant expelled by a nearby nozzle or group of nozzles, respectively.

44. The electronic assembly of claim 43, wherein the second microjet capture manifold further comprises a second collection channel running alongside or beneath the second set of cavities and configured to receive pressurized coolant expelled from the cavities in the second set of cavities, and route the pressurized liquid coolant fluid to the second inlet plenum.

45. The electronic assembly of claim 44, further comprising:(a) a second outlet plenum, in fluid communication with the second collection channel, configured to store pressurized liquid coolant fluid from the second collection channel, and(b) an outlet, attached to the housing and in fluid communication with the second outlet plenum, the outlet configured to permit the pressurized liquid coolant fluid stored in the second outlet plenum to flow out of the electronic assembly.

46. The electronic assembly of claim 45, wherein the second microjet capture manifold further comprises a second set of drainage ports in the interior sidewalls of the second set of cavities or the distal ends of the second set of cavities, the second set of drainage ports being configured to discharge pressurized liquid coolant fluid into the second collection channel.

47. The electronic assembly of claim 45, wherein the second microjet capture manifold further comprises:(a) a second standoff interposed between the second jet plate and second set of cavities;(b) wherein the second standoff is configured to provide sufficient spacing between the nozzles in the second jet plate and the second set of cavities to allow pressurized coolant fluid inside the cavities of the second set of cavities to spill out of the mouths of the cavities and flow into the second collection channel.

48. The electronic assembly of claim 43, wherein the mouths, interior sidewalls and distal ends of the cavities in the second set of cavities are configured to isolate and confine turbulent flows of pressurized liquid coolant fluid induced by the microjets of pressurized liquid coolant fluid striking the interior walls of the cavities, the distal ends of cavities, or both, so that turbulent flows induced by microjets expelled from one nozzle in the second set of nozzles do not interact with turbulent flow's induced by microjets expelled by another nozzle in the second set of nozzles.

49. The electronic assembly of claim 43, further comprising a second seal interposed between the second jet plate and a second section of the housing to prevent pressurized liquid coolant fluid from bypassing the second jet plate and flowing directly into the second microjet capture manifold.

50. The electronic assembly of claim 43, wherein:(a) the second set of nozzles in the second jet plate and the second set of cavities on the first surface of the base plate are arranged such that two or more nozzles in the secon d set of nozzles in the second jet plate are aligned with the mouth of a single cavity in the second set of cavities; and(b) the microjets of pressurized coolant fluid expelled from said two or more nozzles in the second set of nozzles will pass through the mouth of said single cavity in the second set of cavities and strike the interior sidewall of said single cavity, the distal end of said single cavity, or both.

51. The electronic assembly of claim 43, wherein the distal ends of at least some of the cavities in the second set of cavities have an inverted conical shape.

52. The electronic assembly of claim 43, wherein at least some of the cavities in the second set of cavities are cylindrical.

53. The electronic assembly of claim 43, wherein at least some of the cavities in the second set of cavities are rectangular.

54. The electronic assembly of claim 43, wherein at least some of the cavities in the second set of cavities have interior sidewalls that are asymmetrical.

55. The electronic assembly of claim 43, further comprising a second alignment pinhole in the second jet plate to facilitate aligning nozzles in the second jet plate with the mouths of cavities in the second set of cavities on the microjet capture manifold on the second surface of the base plate.

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