Patent Description:
Electronic devices generate heat through power consumption. Excessive heat generation without sufficient cooling can lead to damage and failure of electronic devices. Electronic devices may be cooled by cooling systems such as heat sinks. Heat sinks are passive heat exchangers that transfer heat from electronic devices to a fluid medium.

Document <CIT>, on which the preamble of claim <NUM> is based, <NUM> relates to a metallic heat exchanger tube, in particular for the liquefaction or condensation of vapors on the tube outside.

Document <CIT> relates to a heat exchanger having fluid control elements for deterring the formation of high pressure within the heat exchanger and/or reducing the premature egress of fluid from the heat exchanger caused by the high pressure.

Document <CIT> relates to refrigeration technology fields, in particular to a kind of heat exchanger tube and a heat pump unit.

Document <CIT> relates to a cooling device having a variable cooling capacity mechanism provided on the surface of a component to suppress the temperature rise of the precision electronic component.

Heat sinks can be used to cool electronic devices, e.g., processors, memories, network devices, and other heat generating devices. In computing systems, heat sinks can be used to cool central processing units (CPUs), graphics processing units (GPUs), tensor processing units (TPU), chipsets, and random access memory (RAM) modules, and other electronic devices.

A heat sink is a passive heat exchanger that can transfer heat generated by an electronic device to a lower temperature fluid medium, such as air or a liquid coolant. The fluid medium removes and disperses heat from the electronic device. A heat sink can be used to lower or maintain the temperature of the electronic device, preventing the electronic device from overheating.

The amount of heat that can be removed by a heat sink is dependent on various factors, to include the surface area of the heat sink, the fluid volume and velocity through the heat sink, and the direction of fluid flow through the heat sink. Heat sink performance can be improved by increasing the amount of heat that the heat sink removes from the electronic device. Heat sink performance can also be improved by increasing the rate of heat removal from the electronic device.

The presently claimed subject-matter is defined in independent claim <NUM>.

There is disclosed a heat sink including: a base defining a first side having a base planar surface and a second side opposite the first side; and a plurality of planar fins extending from the base planar surface in parallel disposition relative to each other, each planar fin of the plurality of planar fins comprising: a bottom fin edge coupled to the base planar surface and running parallel a longitudinal axis of the planar fin, a top fin edge that is opposite the bottom fin edge and running parallel the longitudinal axis of the planar fin, a leading fin edge extending from the bottom fin edge to the top fin edge, a trailing fin edge opposite the leading fin edge and extending from the bottom fin edge to the top fin edge, a fin body extending from the bottom fin edge to the top fin edge and having a first side defining a first planar surface and second side opposite the first side defining a second planar surface; and a first set of turbulent structures extending from the first planar surface, each turbulent structure in the first set of turbulent structures defining a longitudinal axis and having a first edge that is parallel to the longitudinal axis and connected to the first planar surface and a second edge opposite the first edged and in free space, the second edge defining a periphery that varies in distance from the first edge along the length of the longitudinal axis; and wherein the periphery of each second edge is shaped such that the fluid flows over the second edge (<NUM>) and is further shaped such that turbulent flow of a fluid is induced in the fluid flowing over the second edge at at least a predefined flow rate.

Furthermore, there is disclosed a planar fin comprising a bottom fin edge coupled to the base planar surface and running parallel a longitudinal axis of the planar fin; a top fin edge that is opposite the bottom fin edge and running parallel the longitudinal axis of the planar fin; a leading fin edge extending from the bottom fin edge to the top fin edge; a trailing fin edge opposite the leading fin edge and extending from the bottom fin edge to the top fin edge; a fin body extending from the bottom fin edge to the top fin edge and having a first side defining a first planar surface and second side opposite the first side defining a second planar surface; and
a first set of turbulent structures extending from the first planar surface, each turbulent structure in the first set of turbulent structures defining a longitudinal axis and having a first edge that is parallel to the longitudinal axis and connected to the first planar surface and a second edge opposite the first edged and in free space, the second edge defining a periphery that varies in distance from the first edge along the length of the longitudinal axis; and wherein the periphery of each second edge is further shaped such that turbulent flow of a fluid is induced in the flow flowing over the second edge at at least a predefined flow rate.

Furthermore, there is disclosed a heat sink including heat sink comprising: a base defining a first side having a base planar surface and a second side opposite the first side; and a plurality of planar fins extending from the base planar surface in parallel disposition relative to each other, each planar fin of the plurality of planar fins comprising: a bottom fin edge coupled to the base planar surface and running parallel a longitudinal axis of the planar fin; a top fin edge that is opposite the bottom fin edge and running parallel the longitudinal axis of the planar fin; a leading fin edge extending from the bottom fin edge to the top fin edge; a trailing fin edge opposite the leading fin edge and extending from the bottom fin edge to the top fin edge; fin body extending from the bottom fin edge to the top fin edge and having a first side defining a first planar surface and second side opposite the first side defining a second planar surface; and means for inducing turbulent flow extending from the first planar surface and that induce turbulent flow of a fluid flowing over the means at at least a predefined flow rate.

Heatsink performance is improved when turbulent flow occurs between the fins when the fluid flows at the predefined rate. To induce turbulent flow, the planar fins of the heat sink include a set of turbulent structures. The turbulent structures extend from a first planar surface of the fin, e.g., a first side of the fin. Each turbulent structure in the first set of turbulent structures defines a longitudinal axis and has a first edge that is parallel to the longitudinal axis and connected to the first planar surface. Each turbulent structure also has a second edge opposite the first edge and in free space. The second edge defines a periphery that varies in distance from the first edge along the length of the longitudinal axis. For example, the periphery can be saw tooth shaped, straight tooth shaped, or even curved. The periphery of each second edge is further shaped such that turbulent flow of a fluid is induced in the fluid flowing over the second edge at at least a predefined flow rate.

Turbulent structures can also be attached to the other side of the heatsink fin and offset from the structures on the first side of the heatsink fin. In this configuration, the turbulent structures extend into the space between heatsinks from both heatsink surfaces. With higher turbulence, the heat sink realizes a higher heat transfer coefficient h that would otherwise be realized with smooth fins. This leads to better convection cooling capabilities. Thus, the principle of this design is to add turbulence enhancement features on the heatsink fins to increase heat transfer coefficient.

These features and additional features are described in more detail below.

<FIG> is a diagram of an example heat sink <NUM> with planar fins <NUM> that include turbulent structures <NUM>. The heat sink <NUM> includes a base <NUM> defining a first side <NUM> having a base planar surface, and a second side <NUM> opposite the first side <NUM>. A set of planar fins <NUM> (e.g., <NUM>-<NUM>. N) extend from the base planar surface <NUM> in parallel disposition relative to each other. Each planar fin <NUM> includes a bottom fin edge <NUM> coupled to the base planar surface <NUM> and running parallel to a longitudinal axis <NUM> of the planar fin <NUM>. Each planar fin <NUM> also is defined by a top fin edge <NUM> that is opposite the bottom fin edge <NUM> and running parallel to the longitudinal axis <NUM> of the planar fin, and is further defined by a leading fin edge <NUM> extending from the bottom fin <NUM> edge to the top fin edge <NUM>, and a trailing fin edge <NUM> opposite the leading fin edge <NUM> and extending from the bottom fin edge <NUM> to the top fin edge <NUM>.

<FIG> is top view of the planar fins <NUM> with turbulent structures <NUM>. Each fin <NUM> defines a fin body <NUM> extending from the bottom fin edge <NUM> to the top fin edge <NUM> and having a first side <NUM> defining a first planar surface and second side <NUM> opposite the first side defining a second planar surface. To avoid congestion in the drawings, like elements for all fins <NUM> are not labeled.

In some implementations, except for exterior fins <NUM>-<NUM> and <NUM>-N, each planar fin <NUM> includes a first set of turbulent structures <NUM>-<NUM> extending from the first planar surface <NUM>, and a second set of turbulent structures <NUM>-<NUM> extending from the second planar surface <NUM>. Exterior fin <NUM>-<NUM>, however, includes only a first set of turbulent structures <NUM>-<NUM> on the first planar surface <NUM>. Conversely, exterior fin <NUM>-N includes only a second set of turbulent structures <NUM>-<NUM> on the second planar surface <NUM>. In other implementations, exterior fins <NUM>-<NUM> and <NUM>-N have turbulent structures <NUM> on both of their respective first planar surface <NUM> and second planar surface <NUM>.

The turbulent structures <NUM> are uniformly spaced apart, and each respective set <NUM>-<NUM> and <NUM>-<NUM> are offset from each other so as to not overly reduce airflow that would otherwise result if the sets <NUM>-<NUM> and <NUM>-<NUM> were not offset.

<FIG> is a side perspective of a turbulent structure <NUM>. Each turbulent structure <NUM> defines longitudinal axis <NUM> and having a first edge <NUM> that is parallel to the longitudinal axis <NUM>. The first edge <NUM> is connected to the planar surface <NUM> or <NUM>. In some implementations, the turbulent structures <NUM> are connected at an acute angle A, as shown in <FIG>. The turbulent structure <NUM> includes a second edge <NUM> opposite the first edge <NUM>. The second edge, as shown in <FIG>, is in free space such that air may flow over the second edge <NUM>. The second edge <NUM> defines a periphery <NUM> (a second edge of which is shown in phantom and offset in <FIG>) that varies in distance from the first edge <NUM> along the length of the longitudinal axis <NUM>. The periphery <NUM> of each second edge <NUM> is further shaped such that turbulent flow of a fluid is induced in the fluid flowing over the second edge <NUM> at at least a predefined flow rate, e.g., at a flow rate induced by a fan <NUM>. As shown in <FIG>, the periphery <NUM> varies linearly in distance from the edge <NUM> from a maximum distance of H to a minimum distance of h, with the relative maximum and minimum spaced apart by a distance d. The values of A, H, h and d can be varied to achieve different heat transfer coefficients. Such heat transfer coefficients can be measured empirically, for example.

The triangular shape of <FIG> is but one example of a periphery that can be used. For example, as shown in <FIG>, a turbulent structure <NUM> with a curved periphery pattern <NUM> can be used. Other periphery patterns can also be used, such as a saw-tooth pattern, a straight tooth pattern, or still other patterns.

In some implementations, the second edge <NUM> has a uniform cross section. In other implementations, however, each second edge <NUM> may include terminal nubs <NUM> to further increase turbulent flow. As shown in <FIG>, the terminal nub <NUM> is pyramidal in shape; however, a variety of other shapes can be used.

Claim 1:
A planar fin (<NUM>) comprising:
a bottom fin edge (<NUM>) coupled to the base planar surface (<NUM>) and running parallel to a longitudinal axis (<NUM>) of the planar fin (<NUM>);
a top fin edge (<NUM>) that is opposite the bottom fin edge (<NUM>) and running parallel to the longitudinal axis (<NUM>) of the planar fin (<NUM>);
a leading fin edge (<NUM>) extending from the bottom fin edge (<NUM>) to the top fin edge (<NUM>);
a trailing fin edge (<NUM>) opposite the leading fin edge (<NUM>) and extending from the bottom fin edge (<NUM>) to the top fin edge (<NUM>);
a fin body (<NUM>) extending from the bottom fin edge (<NUM>) to the top fin edge (<NUM>) and having a first side defining a first planar surface (<NUM>) and second side opposite the first side defining a second planar surface (<NUM>); and
a first set of turbulent structures (<NUM>-<NUM>) extending from the first planar surface (<NUM>), each turbulent structure (<NUM>) in the first set of turbulent structures (<NUM>-<NUM>) defining a longitudinal axis (<NUM>) of the turbulent structure (<NUM>) and having a first edge (<NUM>) that is parallel to the longitudinal axis (<NUM>) of the turbulent structure (<NUM>) and connected to the first planar surface (<NUM>) and a second edge (<NUM>) opposite the first edge (<NUM>) and in free space, the second edge (<NUM>) defining a periphery (<NUM>) that varies in distance from the first edge (<NUM>) along the length of the longitudinal axis (<NUM>) of the turbulent structure (<NUM>); and
characterized in that
the periphery (<NUM>) of each second edge (<NUM>) is shaped such that the fluid flows over the second edge (<NUM>), and is further shaped such that turbulent flow of a fluid is induced in the flow flowing over the second edge (<NUM>) at at least a predefined flow rate.