Micro channel heatsink

The present invention provides a heat sink for transferring heat from a heat source to a coolant fluid and a method of operating the heat sink.

Electrical components such as integrated circuits generate heat. Such heat must be dissipated or cooled as it adversely affects electrical components. Heat sinks have been used to dissipate heat. The heat sink comprises a continuous layer of overlapping channels on a cold plate or base on which the electronic components that generate heat are placed. Such heat sinks are disclosed in US Pat. No. 5,388,635 issued to Gruber and the like. Typically, a flat cold plate or base has parallel passages or channels, all of which extend over the same distance in the cold plate, with the manifold plate overlapping the cold plate. The electronic component is attached to the opposite surface of the cold plate and the coolant is flushed through the aisle to draw heat from the electronic component.<patcit num="1"><text>U.S. Pat. No. 5,388,635</text></patcit>

<p> It is always required to manufacture a heat sink having a low manufacturing cost, a high heat-drawing performance, and a small mass.</p>

<p> The present invention provides a heat sink for transferring heat from a heat source to a coolant fluid and a method of operating the heat sink. This allows coolant to flow into the inlet manifold channel that extends into the inlet edge of the manifold, where the coolant flow is pushed downward into parallel and spaced microchannels that extend across the manifold channel. The coolant is then turned upwards into and out of an outlet manifold channel that extends into and alternates with the inlet manifold channel at the outlet edge of the manifold. Keep the base width of the microchannel within the range of 40 μm to 100 μm, the base height of the microchannel within the range of 200 μm to 400 μm, and the height of the manifold through the manifold channel within the range of 1000 μm to 3000 μm. Improve efficiency by keeping the manifold width of the manifold channel within the range of 350 μm to 1000 μm.</p><p> Accordingly, the present invention provides heat sinks that maximize heat transfer by optimizing the operational relationships of parameters that affect coolant flow and heat transfer.</p><p> Other advantages of the present invention will be readily understood. This is because it will be better understood by reading the following detailed description in connection with the accompanying drawings.</p>

With reference to the accompanying drawings, the same reference number indicates the corresponding parts over several figures. The heat source 22, that is, the heat sink 20 for transferring heat from the electronic component to the coolant fluid is shown schematically.

The heat sink 20 is formed by a housing including a lid 24 and a base 26. Base 26 is a flat cold plate with microchannels 28 parallel to the top and bottom surfaces. All of these microchannels extend over the same distance, and each microchannel has a base width bw and a base height bh within the top surface of the base.

A manifold plate 30 having an upper surface and a lower surface forming a manifold thickness mt is arranged with the lower surface overlapping the microchannel 28. The manifold plate has spaced edges 32 that extend between the ends 34. The lid 24 has a perimeter that engages the base 26 and an inner shoulder portion 36. The inner shoulder portion 36 engages with the end 34 of the manifold plate 30 to form a recessed surface 38 in the periphery that engages with the upper surface of the manifold plate 30. The edge 32 of the manifold plate 30 forms an inlet edge 32 (right side of the figure) and an exit edge 32 (left side of the figure). Each of these edges is spaced from the shoulder 36, forming an inlet plenum between the inlet edge 32 and the shoulder 36 and exiting between the exit edge 32 and the shoulder 36. Form a plenum. The inlet conduit 40 extends into the lid 24 to allow the fluid to flow into the inlet plenum, and the outlet conduit 42 extends into the lid 24 to drain the fluid from the outlet plenum.

The manifold plate 30 has an inlet manifold channel 44 extending into the inlet edge 32 and an outlet manifold channel 44 extending into the outlet edge 32, each of which has a relative edge 32 on the opposite side. Terminate in a spaced relationship. The inlet manifold channels 44 alternate with the outlet manifold channels 44 to form rectangular cells. As shown in FIG. 4, X indicates the flow in and out of channels 44 and 46, and O indicates the flow out of channels 44 and 46. Due to this flow configuration, the pressure drop is small. This is because the flow contracts when it enters the microchannel 28 and expands when the flow reverses and exits the microchannel 28. A wall thickness wt is formed between the manifold channels 44, 46, i.e., exists between the manifold channels 44, 46, and the inlet manifold channels 44 alternate from the outlet edge 32 to the outlet manifold channels 46. Manifold channels 44, 46 have a manifold width mw and a manifold height mh equal to the manifold thickness mt.

The lid 24 and the base have a circular outer shape and include a radially extending ear 48. These ears 48 are provided so as to extend in the radial direction for meshing and engaging, and form a bolt hole for receiving a bolt to seal the lid 24 to the base with the manifold sandwiched between them. .. Place a suitable gasket between the mating parts.

As will be appreciated, manifold channels 44, 46 extend transversely across the base microchannel 28. This causes the coolant to flow away from the heat source 22 engaged to the outside of the base from the inlet conduit 40 to the inlet plenum and into the inlet manifold channel 44, as shown in FIGS. 4 and 5. Forces the flow downwards into the microchannel 28, where the coolant diverts upwards into the outlet manifold channel 46 and enters the outlet plenum to exit the outlet conduit 42. For maximum operating efficiency, the base width bw of the microchannel 28 is maintained in the range of 40 μm to 100 μm, the base height bh into the base of the microchannel 28 is maintained in the range of 200 μm to 400 μm, and the manifold. The manifold height through the manifold thickness of channels 44, 46 is maintained in the range of 1000 μm to 3000 μm, and the manifold width mw of manifold channels 44, 46 is maintained in the range of 350 μm to 1000 μm. Furthermore, the wall thickness of the microchannel 28 is 50 μm. For complete understanding, the heat generation area of the heat source 22 has a predetermined ratio of 0.7 to 1 to the effective heat transfer area of the lower surface of the base provided with the microchannel 28.

Therefore, the present invention provides a method of transferring heat from the heat source 22 to the coolant fluid. This heat transfer method causes coolant to flow into the inlet manifold channel 44 extending into the inlet edge 32 of the manifold, where the flow is parallel and spaced extending across the manifold channels 44, 46. Push down into the microchannel 28 (indicated by X in FIG. 4), redirect the coolant upward (indicated by O in FIG. 4), extend into the outlet edge 32 of the manifold and alternate with the inlet manifold channel 44. It is done by putting it in the exit manifold channel 46 and exiting it. Further, in the heat transfer method, the base width bw of the microchannel 28 is maintained in the range of 40 μm to 100 μm, the base height bh into the base of the microchannel 28 is maintained in the range of 200 μm to 400 μm, and the manifold channel is maintained. This is done by keeping the manifold height mh of 44, 46 in the range of 1000 μm to 3000 μm and the manifold width mw of manifold channels 44, 46 in the range of 350 μm to 1000 μm.

The method is further characterized in that the flow rate of coolant through manifold channels 44, 46 and microchannel 28 is maintained at 0.2 gallons (about 0.757 liters) to 0.3 gallons (about 1.135 liters) per minute.

With reference to FIG. 6, the operation of the heat sink 20 incorporated in the liquid cooling system 50 is outlined. A working fluid moving device, such as a pump 52, moves a flow of cooling fluid, which is usually liquid, through a cooling fluid storage tank 54 that stores excess cooling fluid. Pump 52 moves the cooling fluid through the heat exchanger and dissipates heat from the cooling fluid. The heat exchanger includes a fan 56 and a radiator 58. The radiator 58 may be a well-known type of radiator that includes tubes and has cooling fins between the tubes, with the cooling fluid passing through the tubes and the air pumped through the radiator 58 by the fan 56. Heat exchange between them.

Obviously, many modifications and modifications of the present invention can be made in the light of the above teachings. The present invention can be carried out within the scope of the claims in aspects other than those specifically described.

<figref num="1">FIG. 1 is a diagram showing a lid in an assembled state in a virtual line according to a preferred embodiment of the heat sink of the present invention.</figref><figref num="2">FIG. 2 is a partial cross-sectional perspective view with a part removed.</figref><figref num="3">FIG. 3 is an exploded view.</figref><figref num="4">FIG. 4 is a schematic plan view showing the relationships between the various flow channels.</figref><figref num="5">FIG. 5 is a schematic cross-sectional view showing the relationships between the various flow channels.</figref><figref num="6">FIG. 6 is a schematic diagram of a system for moving coolant through the heat sink of the present invention.</figref>

Code description

20 Heat Sink 22 Heat Sink 24 Lid 26 Base 28 Micro Channel 30 Manifold Plate 32 Edge 34 Edge 36 Shoulder 38 Recessed Surface 40 Inlet Conduit 42 Outlet Conduit 44 Inlet Manifold Channel 46 Outlet Manifold Channel 48 Ear 50 Liquid Cooling System 52 Pump 54 Storage tank 56 Fan 58 Radiator bh Base height bw Base width mh Manifold height mt Manifold thickness mw Manifold width wt Wall thickness