Fluid jet cooling device for electronic equipment

Abstract

The present invention relates to a cooling device for electronic components configured to generate a jet of a cooling fluid impacting suitable structures of increased heat transfer to improve heat exchange efficiency.

Description

[0001] FLUID JET COOLING DEVICE FOR ELECTRONIC EQUIPMENT

[0002] DESCRIPTION

[0003] Technical field of the invention

[0004] The present invention relates to the field of heat exchangers.

[0005] The present invention, more in detail, relates to a cooling device configured to cool down electronic components exploiting the fluid-dynamics of a jet of refrigerating fluid impacting on structures with increased thermal exchange suitable implemented to improve the overall efficiency of the device.

[0006] Background

[0007] The thermal management and, in particular, the cooling of electronic equipment is becoming an increasingly demanding activity due to the exponential growth of computational power per area unit achieved by the various components and processing units. The need for having available more computational power is guided by applications such as the artificial intelligence, requiring a huge amount of parallel computing.

[0008] It is known in the art arranging cooling systems comprising heat dissipation structures made in the form of pin, the so-called “pin fin”. They are substantially elements projecting from a heated surface in contact with the electronic component and which usually guarantee a high heat transfer area and a higher heat transfer coefficient. The cross section of such pins can assume different shapes, for example it can have a regular geometry or it can vary along the pin development direction. However, the efficiency of such structures (that is the heat transfer area transferring effectively the heat to the fluid) is modest. In the heat exchange systems, in fields different from the electronic applications, a heat transfer mechanism is further known providing the generation of an impact (refrigerating) fluid jet (jet impingement). Such mechanism represents a particular case of convection of force, wherein the cooling fluid is forced to flow through one or more nozzle. The resulting flow is then introduced in the region where the heat transfer takes place. Due to the fluid-dynamic features of a jet, the heat transfer coefficient is higher than a conventional flow flowing at the area which has to be cooled down.

[0009] However, the known cooling systems, including those with liquid, which are intrinsically better than those based on air circulation, require improvements to guarantee performance and efficiency in the heat exchange so as to guarantee an optimal operation and safety of electronic equipment.

[0010] Summary of the invention

[0011] The technical problem placed and solved by the present invention is then to overcome the above-illustrated problems and, in particular, to provide a cooling device, in particular for coupling with an electronic component, as defined in claim 1.

[0012] Preferred features of the invention are set forth in the depending claim.

[0013] The cooling device of the invention, in general terms, is a heat exchanger and it is configured to receive a cooling fluid and to remove heat from a heat source. In particular, the cooling device is configured to remove the heat generated by a component of electronic equipment, such as for example a processor, by releasing such heat to said cooling fluid.

[0014] In general terms, the device comprises a housing for a plurality of heat transfer elements, an inlet and outlet for the refrigerating fluid. The heat transfer means are carried by a base plate of the device. The base plate comprises a first surface configured to be in direct or indirect thermal contact with the heat source and a second surface opposite the first surface comprising said plurality of heat transfer elements.

[0015] The latter are disposed on, and extend substantially perpendicularly from, the second surface. Each one of the heat transfer elements comprises a root, an end and a body between the root and the end, and each one thereof is connected monolithically with the base plate at the root.

[0016] Such heat transfer elements are formed from material of the base plate by skiving or by cutting and lifting the material of the base plate.

[0017] The device comprises means for guiding the refrigerating fluid flow which is configured to establish a path of the fluid flow from the above-mentioned inlet in the device to the plurality of heat transfer elements and from the plurality of heat transfer elements to said outlet of the fluid from the device.

[0018] Fluid jet generating means is arranged in the fluid path between the fluid inlet and the plurality of heat transfer elements.

[0019] Such jet generating means is configured to generate a plurality of the fluid jets when the fluid flows from the inlet to the plurality of heat transfer elements. The configuration of the device is so that the so-generated fluid jets impact at least the ends of the heat transfer elements according to a direction substantially perpendicular to the second surface of the base plate.

[0020] It will be appreciated that such solution combines the advantages in terms of heat exchange efficiency which can be obtained from the fluid-dynamic conditions of a refrigerating fluid jet with the advantages due to the impact of such jet on suitably formed heat transfer elements and so as to implement a compact structural configuration of a device for cooling electronics components.

[0021] The synergic technical effect of such combination further reveals in a “countercurrent” arrangement of the temperature profiles associated to the plurality of heat transfer elements and to the direction of the fluid jet impacting thereon. In this regard, the efficiency of a heat transfer element, such as for example one fin or one pin, in fact is defined as the relationship between the effective thermal exchange rate and the ideal thermal exchange which would happen if its own structure were wholly at the same temperature from the root to the end. In other words, the efficiency (of the thermal exchange) takes also into account the additional conductive thermal resistance of the heat transfer element itself.

[0022] According to the present invention, the heat transfer elements develop structurally so that a temperature profile is determined thereon which varies along a parallel direction, opposite that of the temperature profile of the refrigerating fluid flow hitting them (counter-current arrangement) and the thermal exchange efficiency is then increased. Vice versa, as it often happens in the known solutions, when the transfer elements are in a crossed flow arrangement, that is their temperature profile varies according to a direction perpendicular to the temperature profile of the fluid flow, the exchange efficiency is smaller.

[0023] Moreover, the presence of heat transfer elements in form of protrusions from the base plate allows to increase the average coefficient of heat transfer with the refrigerating fluid. In absence of structures configured as provided by the present invention, the fluid jet impacting the base plate would determine a stagnation area, on the latter, with reduced exchange coefficient. Differently, according to the invention, the presence of transfer elements to occupy the stagnation area with its own structure, in particular at least the root or even the body, guarantees an increase in the average coefficient of heat exchange with the refrigerating fluid.

[0024] Other advantages, features and use modes of the present invention will result evident from the following detailed description of some embodiments, shown by way of example and not for limiting purposes.

[0025] Brief description of figures The figures of the enclosed drawings will be referred to, wherein:

[0026] ■ Figure 1 shows a top and a bottom perspective view of the main body of the cooling device according to a preferred embodiment of the present invention;

[0027] ■ Figure 2 shows an embodiment of the fluid jet generating means, illustrated in isolation and in configuration coupled with the body of the device shown in Figure 1 ;

[0028] ■ Figure 3 shows a supporting component, illustrated in isolation and in configuration coupled with the jet generating means of Figure 2;

[0029] ■ Figure 4 shows the base plate of the device of the present invention, illustrated in isolation and in configuration coupled with the body of the device shown in Figure 1 ;

[0030] ■ Figures 5a-5c show an element for coupling the device of the present invention according to a preferred embodiment, respectively according to a view in isolation (a) and coupled with the device as shown in Figure 4 according to a top view (b) and bottom view (c).

[0031] ■ Figure 6 and Figure 7 show, each one, a cutout of the cooling device of the present invention with evidence of the path of the refrigerating fluid passing therethrough.

[0032] ■ Figure 8 shows a constructive detail of the heat transfer elements according to a preferred embodiment of the present invention.

[0033] The thicknesses and the curvatures shown in the above-mentioned Figures have to be meant as purely exemplifying and they are not necessarily shown in proportion.

[0034] Detailed description of preferred embodiments The present invention will be described hereinafter by making reference to the above-mentioned Figures.

[0035] By firstly referring to Figure 4, an overall view of a cooling device 100 according to the present invention is shown.

[0036] Said cooling device 100 is a heat exchanger suitable to the use in association with electronic systems, power electronics and data centres.

[0037] In particular, the cooling device of the invention is used as evaporator and it results to be suitable for cooling electronic components, such as for example processing units, or however to be used in equipment for cooling electronic systems.

[0038] The cooling device 100 has reduced overall dimensions and it comprises a first surface, or outer surface 21 , configured to be in direct or indirect thermal contact with a heat source. In particular, such surface is provided for the coupling with the (not shown) electronic component to be cooled down. The outer surface 21 can be coupled thermally with the electronic component through an interface material, for example thermal paste or pads.

[0039] By further referring to Figure 1 the main body 10 of the cooling device 100 is shown. The main body 10 preferably has a substantially quadrilateral geometry.

[0040] It is to be noted that the outer surface 21 is carried by a base plate 20, visible in Figure 4, coupled with the main body 10 of the device 100. Said outer surface 21 is preferably planar. The main body 10 and the base plate 20 are joined preferably through friction welding.

[0041] The base plate 20 comprises a second surface, or inner surface 22, opposite the outer surface 21 , and a plurality of heat transfer elements (not shown in Figure 4) arranged on the second surface 22 extending substantially perpendicularly from the latter.

[0042] In the present context, under the expression “heat transfer element” or the like, a heat exchange enhancement structure is meant, carried by a substantially planar surface. A preferred embodiment of said heat transfer elements is shown in Figure 8, designated with reference 23 and they will be described in greater detail hereinafter.

[0043] The main body 10 further has an inlet 11 and an outlet 12 for a cooling fluid intended to pass through the device 100. In the illustrated example, said inlet 11 and outlet 12 are arranged in axis, but alternative configurations are not excluded.

[0044] The used cooling fluid, preferably, is a single-phase fluid, in particular liquid phase fluid, for example mixtures of water and glycols, or diathermic oils.

[0045] The main body 10 can include anchoring means, for example a plate-like element 50 as shown in Figure 5a, to be coupled with the main body (Figure 5b and 5c) for an even removable fixing of the device 100 with the electronic component to be cooled down.

[0046] Going back to Figure 1 , the inlet 11 and the outlet 12 are in fluid communication therebetween through a thermal exchange chamber 13 positioned at the above- mentioned outer surface 21 intended to the contact with the device to be cooled down. Said outer surface 21 preferably extends for a width at least equal to the planar extension of the thermal exchange chamber 13.

[0047] Advantageously, the thermal exchange chamber 13 results to be interposed between the inlet 11 and the outlet 12. Such solution offers advantages in terms of reduced vertical overall dimensions of the device 100.

[0048] The thermal exchange chamber 13 is inside the device 100. In particular, the thermal exchange chamber 13 is inside a housing 10a of the main body 10 and it is shaped so that an inlet collector 14 inside the main body 10 at the thermal exchange chamber 13 remains defined.

[0049] Said inlet collector 14 is in fluid communication with the inlet 11 of the fluid in the device 100 and the thermal exchange chamber 13 results to be interposed between said collector 14 and the outlet 12 for the fluid from the device 100.

[0050] Advantageously, the configuration of the device 100 is so that the thermal exchange chamber 13 surrounds the inlet collector 14 and is in communication with said fluid outlet 12.

[0051] With further reference to Figure 2, the thermal exchange chamber 13 and the collector 14 are in communication therebetween through means 40 for generating a jet of the cooling fluid.

[0052] The device 100 then comprises means for guiding the refrigerating fluid flow, configured to establish a fluid path, from the inlet 11 to the plurality of heat transfer elements 23 and from the plurality of heat transfer elements 23 to the outlet 12.

[0053] Said jet generating means 40 is arranged in the above-mentioned fluid path, between the inlet 11 , or the collector 14, and the plurality of heat transfer elements 23. The jet generating means 40 is configured to generate a plurality of fluid jets j once the fluid passes through them and which are intended to impact the plurality of heat transfer elements 23.

[0054] In the illustrated embodiment, the jet generating means comprises a perforated plate 40. Preferably, the plate 40 is implemented starting from metal material, for example a metal sheet, whereon a plurality of through holes 4 is obtained, preferably through laser perforation.

[0055] The jet generating means 40 is coupled with the main body 10, in particular it defines a (perforated) wall of the inlet collector 14 by confining (spatially and not fluidically) the fluid entering a distribution chamber. Such design selection allows to distribute uniformly in the collector 14 the refrigerating fluid entering the device 100 and to force it to flow through the plate 40 for generating fluid jets /

[0056] As it is visible in the illustrated example, the jet generating means 40 is arranged in front of the base plate 20, in particular it faces the inner surface 21 and it is spaced apart therefrom.

[0057] Advantageously, with reference to Figure 3, the jet generating means can be kept in position on the main body 10 by a support 45. Said support 45, apart from guaranteeing its correct positioning, performs the function of spacer and provides the required optimized distance between the jet generating means 40 and the heat transfer elements 23.

[0058] In the illustrated example the support 45 is an element perimetral to the jet generating means 40, that is an element abutting at an edge region outside the portion of the plate 40 having the through holes 41 therethrough the fluid jets j form.

[0059] The configuration of coupling between base plate 20, main body 10 and jet generating means 40 is preferably so that the selected heat transfer elements 23 come in abutment with the jet generating means 40 through an end portion thereof. Said selected heat transfer elements do not include, preferably, heat transfer elements facing the jet generating means 40, in particular the plurality of through holes 41 of the plate.

[0060] Figures 6 and 7 show the guiding means and the path of the refrigerating fluid passing through the device 100 of the invention. The fluid enters the device from the inlet 11 and reaches the collector 14. The fluid is forced to pass through the jet generating means 40, in particular the plurality of holes 41 , and impacts the heat transfer element 23 (not shown in figures) carried by the base plate 20 inside the thermal exchange chamber 13. The fluid removes heat from said heat transfer elements 23 and passes through the regions of the exchange chamber 13 surrounding the collector 14 towards the outlet 12 of the device 100.

[0061] With further reference to Figure 8, generally, each one of the heat transfer elements has said end 23c and a root 23a, connected therebetween by a body 23b. According to the invention, the plurality of heat transfer elements is connected to the root 23a and monolithically to the base plate 20.

[0062] As anticipated above, the fluid jets j impact (at least) the ends 23c of the heat transfer elements 23, in a direction substantially perpendicular to the surface 22 of the base plate 20 carrying them.

[0063] The heat transfer elements 23 are formed from material of the base plate 20 by skiving or cutting and lifting material of the base plate 20 itself. The heat transfer elements 23 project from the surface 22 of the base plate 20 preferably by a height of at least 4 mm and no more than 6 mm.

[0064] The heat transfer elements can be implemented as fins (straight fin) that is structures developing according to a preferential direction, for example longitudinal and with regular section, for example rectangular. Such structures are parallel therebetween and so as to define therebetween uninterrupted lanes performing the function of (micro)channels of fluid flow in the thermal exchange chamber 13.

[0065] Such embodiment, not shown in figures can provide a pitch between the fins, measured perpendicularly to the extension of the fins themselves, equal to at least 0.85 mm and no more than 2.1 mm, equivalent to a density of 12 - 30 fins per inch. A density of fins outside said range of values however is possible from the point of view of device manufacturing, but it does not allow to optimize the thermal performances which can be obtained according to the configurations of the device according to the invention and described herein.

[0066] According to embodiment variants, illustrated by way of example in Figure 8, the heat transfer elements can be implemented as pins 23 (pin fin), that is an uninterrupted finned structure, which does not have a development along the plane of the surface 22 of the base plate 20, but a development in the direction orthogonal to the surface of the base plate 20 carrying them.

[0067] The geometry of this embodiment of the heat transfer elements has the advantage of spreading the jet of fluid flow coming from the jet generating means in all directions, by avoiding the thermal shading and reducing the pressure drops.

[0068] Advantageously, the pitch or spacing of the transfer elements, be they fins or pins, can vary. For example, the pitch of heat transfer elements adjacent to a central region of the base plate 20 can be smaller than the pitch of heat transfer elements adjacent to the periphery of the base plate 20.

[0069] The fact of varying the pitch of the heat transfer elements allows to optimize the heat exchange efficiency, by obtaining a more dense distribution thereof (and / or the prediction of a corresponding density of through holes 41 on the jet generating means 40) in regions of the thermal exchange chamber 13 wherein the heat flow results to be higher (hot points).

[0070] In combination or in alternative, according to embodiment variants of the invention, the jet generating means 40 can be configured to generate not uniformly distributed jets j. In particular, the plurality of through holes 41 of the plate can have different diameters and be distributed according to not regular patterns on the plate. In this way advantageously it is possible to obtain a not uniform exposure on the heat transfer elements 23 and to generate jets j according to spatial distributions to send a predetermined (or null) refrigerating fluid flow in a specific area of the base plate 20.

[0071] For example, the through holes 41 can be concentrated and / or be absent in determined areas of the plate facing the transfer elements 23.

[0072] Analogously, even the inlet 11 , the collector 14, the thermal exchange chamber 13 and the outlet 12, components housing the refrigerating fluid it its path through the device 100, could be implemented according to suitable shapes and sizes (even different from the illustrated and described ones) to transfer more or less refrigerant to / from determined areas of the base plate 20.

[0073] In embodiments, said pins 23 are made by skiving or cutting and lifting material of the base plate 20 to form a plurality of fins extending parallelly to each other in a first direction and subsequently by skiving or cutting and lifting the plurality of previously obtained fins in a second direction substantially perpendicular to the first direction.

[0074] The pins 23 can be implemented so that the section transversal to its own development direction varies along the extension of the pin itself. The pin, for example, can have a development direction following a twist and an overall twisted shape between the root 23a and the end 23c.

[0075] The twisted shape, for example according to a helical profile which indeed develops vertically, of a plurality of the pins implemented according to the invention, that is by skiving or microdeformation (that is cutting and lifting of material), advantageously provides an (additional) vortex effect to the fluid jet impacting thereon, which results in an increase in the heat transfer coefficient.

[0076] Generally, fins or pins implemented through techniques (for example forging) different from those mentioned above do not produce such advantageous effects. Moreover, through skiving techniques, the manufacturing cycle time is considerably reduced. The cutting and lifting of the material further allows, in case of transfer elements implemented as pins, to provide automatically a twist to the structure of the pin which is implemented by obtaining in a simple way helical, or generally twisted, development elements.

[0077] According to an advantageous embodiment combination of the present invention, the base plate 20 comprises twisted pins 23 facing the perforated region of the jet generating means 40.

[0078] In particular, at least a through hole 41 of the plate 40 is configured to generate a swirling flow of the fluid entering the collector 14. Preferably said through hole 41 has ribs and / or grooves, for example with helical extension, on its inner surface.

[0079] Advantageously, the orientation of the pins’ twist can be in agreement (or discordant) with the orientation of the swirling flow generated by the through hole 41 situated near, or facing, such pin, depending upon the turbulent motion wished inside the thermal exchange chamber 13.

[0080] The present invention has been sofar described with reference to preferred embodiments. It is to be meant that other embodiments belonging to the same inventive core may exist, as defined by the protective scope of the herebelow reported claims.

Claims

CLAIMS1. A cooling device (100) to remove heat from a heat source and to release heat to a fluid, comprising:■ a housing (10a),■ a fluid inlet (11 ) and a fluid outlet (12),■ a base plate (20) having a first surface (21 ) configured to be in direct or indirect thermal contact with a heat source, a second surface (22) opposite the first surface (21 ) and a plurality of heat transfer elements (23) arranged on the second surface (22) and extending substantially perpendicularly from the second surface (22), each one of the heat transfer elements having a root (23a), an end (23c) and a body (23b) between the root and the end, said heat transfer elements (23) connected monolithically with the base plate (20) at the root (23a) of each heat transfer element (23),■ flow guiding means configured to establish a flow path from the fluid inlet (11 ) to the plurality of heat transfer elements (23) and from the plurality of heat transfer elements (23) to the fluid outlet (12),■ jet generating means (40) arranged in the fluid path between the fluid inlet (11 ) and the plurality of heat transfer elements (23), wherein the jet generating means (40) is configured to generate a plurality of fluid jets (j) when the fluid flows from the fluid inlet (11 ) to the plurality of heat transfer elements (23), wherein the fluid jets (j) impact at least the ends (23c) of the heat transfer elements (23) in a direction substantially perpendicular to the second surface (22) of the base plate (20), wherein the heat transfer elements (23) are formed from material of the base plate (20) by skiving or cutting and lifting of material of the base plate (20).

2. The cooling device (100) according to claim 1 , wherein the heat transfer elements (23) have a height of at least 4 mm and no more than 6 mm.

3. The cooling device (100) according to claim 1 or 2, wherein the heat transfer elements are fins extending parallelly to each other.

4. The cooling device (100) according to claim 3, wherein the fin pitch, measured perpendicularly to the fin extension, is at least equal to 0.85 mm and no more than 2.1 mm.

5. The cooling device (100) according to claim 4, wherein the fin pitch varies, in particular, the fin pitch adjacent to the centre of the base plate (20) is smaller than the pitch of the fins adjacent to the periphery of the base plate (20).

6. The cooling device (100) according to claim 1 or 2, wherein the heat transfer elements are pins (23).

7. The cooling device (100) according to claim 6, wherein the pins (23) are made by skiving or cutting and lifting the material of the base plate (20) to form a plurality of fins extending parallel to each other in a first direction and subsequently by skiving or cutting and lifting the plurality of fins (23) in a second direction substantially perpendicular to the first direction.

8. The cooling device (100) according to claim 6 or 7, wherein said pins (23) are twisted between the root (23a) and the end (23c) of a pin.

9. The cooling device (100) according to anyone of claims 6 to 8, wherein the spacing between adjacent pins (23) varies, in particular, the spacing between adjacent pins (23) at the centre of the base plate (20) is smaller than the spacing between adjacent pins (23) at the periphery of the base plate (20).

10. The cooling device (100) according to anyone of the preceding claims, wherein the jet generating means comprises a substantially flat element (40) comprising a plurality of through holes (41 ) arranged as a matrix.

11. The cooling device (100) according to claim 10, wherein at least a through hole (41 ) is configured to generate a swirling flow of the fluid.

12. The cooling device (100) according to claim 11 , wherein at least a through hole (41 ) has ribs and / or grooves with helical extension on its own inner surface.

13. The cooling device (100) according to claim 11 or 12 including pins (23) according to claim 8, wherein the twist orientation of at least one pin is corotating with the orientation of the swirling flow generated by the through hole (41 ) facing in proximity of said one pin.

14. The cooling device (100) according to claim 11 or 12 including pins (23) according to claim 8, wherein the twist orientation of at least one pin is counter- rotating with respect to the orientation of the swirling flow generated by the through hole (41 ) facing in proximity of said one pin.

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