A design method for cold plate flow path and liquid cooling plate

Abstract

The present invention provides a design method for a cold plate flow path and a liquid cold plate, the design method comprising the following steps: drawing a cold plate schematic diagram; establishing an algorithm; generating a flow path: selecting an array corresponding to the smallest value of the shortest distances from all origins to confluence points, drawing a cold plate flow path diagram including origins, confluence points, nodes and paths, and for multiple groups of routes with the same minimum value, selecting a route as a flow path design result based on actual needs in combination with thermal simulation. The present invention combines thermal design problems with graph theory and operations research, converts the flow path design problem into a shortest path problem with constraints that increases weights, obtains the lowest flow resistance under the premise that the flow path passes through the heat source points of each device to ensure the heat dissipation performance of the cold plate, and fully considers the reliability of engineering applications and the practicality of production and processing, providing a standard reference for the design of cold plate flow paths for electronic devices.

Description

Technical Field

[0001] The invention belongs to the field of cooling technology and relates to a design method for a cold plate flow channel path and a liquid cooling plate. Background Art

[0002] Liquid cooling plates are commonly used as structural components for electronic devices and can cool down electronic devices. Flow path design is a key issue in liquid cooling heat dissipation design for electronic devices.

[0003] Traditional methods rely solely on experience or trial and error to design the flow channel. For example, CN209571688U discloses a water cooling plate for pumping lasers. The flow channel design uses multiple serpentine bends and passes under the heat source as much as possible. There is a lack of quantitative mathematical solution methods, and the design is blind.

[0004] Mathematical modeling attempts have been introduced into the cold plate flow channel design. For example, CN107122527B discloses a cold plate flow channel design method based on topology optimization. The topology optimization technology is used to obtain a cold plate flow channel with better heat dissipation performance, better temperature uniformity, and smaller flow resistance. However, the designed flow channel has a special-shaped structure, and traditional cold plate flow channel processing methods such as brazing or electron beam welding are not applicable, making it difficult to promote and apply in engineering. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a design method for a cold plate flow path, which specifically includes the following steps:

[0006] Draw a schematic diagram of the cold plate, take the inlet and outlet of the cold plate flow channel as the origin and confluence point respectively, and mark the heat source position as the node;

[0007] Establishing the algorithm includes the following steps:

[0008] Step 1: declare an array dis to save the shortest distances from the origin to each node and from the origin to the confluence point, and declare a point set T to save the existing shortest path node set;

[0009] Step 2: Initially, the point set T only has the origin, and dis is initialized; the initialized array dis includes the distance from the origin to itself, which is 0; it also includes the shortest distance from the origin to each node and from the origin to the confluence point; in the initial state, when the origin cannot directly reach a node, the shortest distance between the origin and the node is set to infinity;

[0010] Step 3: Select the minimum value from the array dis, which is the shortest distance corresponding to the shortest path from the origin to the corresponding node, and add the corresponding node to the point set T;

[0011] Step 4: Determine whether the path length from the origin through the newly added node to other nodes is shorter than that from the origin directly. If so, update the array dis, that is, replace the path length from the origin directly to the node with the path length from the origin through the newly added node to other nodes. If not, keep the array dis unchanged.

[0012] Step 5. Continue to find the minimum value in dis and repeat steps 3-5 until the point set T contains all the points in the graph.

[0013] Generate flow channel: select the array dis corresponding to the smallest value of the shortest distance from all origins to confluence points, and draw a cold plate flow channel diagram including origins, confluence points, nodes and paths based on the array dis and its corresponding point set T. For multiple groups of routes with the same minimum value, select the route as the flow channel design result based on actual needs in combination with thermal simulation.

[0014] Furthermore, the flow channels between nodes are arranged in a horizontal and vertical form to avoid the structural holes and screw holes of the cold plate, and the unreachable distance and the bend angle weighted distance are defined. The unreachable distance means that the distance between non-adjacent nodes is defined as infinite, and the bend angle weighted distance means that the local resistance of the bend angle is converted into the extended resistance, and the bend angle is converted into the distance between nodes. Therefore, the shortest distance from the origin to each node and from the origin to the confluence point includes the lateral distance, the longitudinal distance and the bend angle weighted distance, and the lateral distance and the longitudinal distance are determined by the flow channels between nodes being arranged in a horizontal and vertical form.

[0015] Furthermore, the actual requirements include the lowest heat source temperature, the best temperature uniformity and the lowest flow resistance.

[0016] The present invention also provides a liquid cooling plate, comprising a liquid inlet and a liquid outlet, wherein a cold plate flow channel is formed between the liquid inlet and the liquid outlet, and characterized in that the cold plate flow channel is realized by any of the above-mentioned cold plate flow channel path design methods.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. Compared with the current liquid cooling of electronic devices, which only relies on experience or trial and error to design the flow channel, a quantitative mathematical solution method is provided to obtain a cold plate with excellent heat dissipation and flow resistance performance, thereby improving the design efficiency of the liquid cooling cold plate flow channel.

[0019] 2. Compared with the special-shaped flow channel design obtained by topology optimization and other methods, while ensuring the heat dissipation and flow resistance performance of the cold plate, the regular flow channel design improves the feasibility of cold plate production and processing, and has higher engineering practical value.

[0020] The present invention overcomes the shortcomings of the prior art and provides a cold plate flow channel design method with an optimal path. The method combines thermal design problems with graph theory and operations research, converts the flow channel path design problem into a shortest path problem with added weights and constraints, obtains the lowest flow resistance under the premise of ensuring the heat dissipation performance of the cold plate while the flow channel passes through the heat source points of each device, and fully considers the reliability of engineering applications and the practicality of production and processing, providing a standard reference for the design of cold plate flow channels for electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is an example diagram of the shortest path optimization algorithm of an embodiment of the present invention.

[0022] Figure 2 Schematic diagram of the heat source distribution state of the liquid-cooled cold plate according to an embodiment of the present invention.

[0023] Figure 3 Schematic diagram of the design of the cold plate flow path 1 according to an embodiment of the present invention.

[0024] Figure 4 It is a schematic diagram of the design of the cold plate flow path 2 according to an embodiment of the present invention.

[0025] Figure 5 Schematic diagram of the design of the cold plate flow path 3 according to an embodiment of the present invention.

[0026] Figure 6 Schematic diagram of the design of the cold plate flow path 4 according to an embodiment of the present invention.

[0027] Figure 7 Graph showing the fluid thermal simulation results for path 2 of an embodiment of the present invention.

[0028] Figure 8 Graph showing solid thermal simulation results for path 2 of an embodiment of the present invention.

[0029] Description of reference numerals:

[0030] The first heat source to the sixteenth heat source 0-15, the flow channel outlet 16, the flow channel inlet 17, the heat expansion plate 19, the structural hole 20, and the screw hole 21. DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0032] The basic ideas of the design of this embodiment include:

[0033] 1. The cold plate has a single inlet and a single outlet at a fixed position. The design takes into account the reliability of engineering applications and the practicality of production and processing, and uses a straight single-channel flow channel to connect the inlet and outlet.

[0034] 2. The flow channel must pass through the point below the heat source of each device and avoid the cold plate opening.

[0035] 3. The shortest flow path and the least number of corners must be ensured to reduce flow resistance losses.

[0036] Based on this design idea, the thermal design problem can be combined with graph theory and operations research, and the flow path design problem can be converted into a shortest path problem with constraints and increased weights.

[0037] Therefore, this embodiment provides a method for designing a cold plate flow path, which specifically includes the following steps:

[0038] Draw a schematic diagram of the cold plate, take the inlet and outlet of the cold plate flow channel as the origin and the confluence point respectively, and mark the heat source position as the node; the flow channels between the nodes are arranged in a horizontal and vertical form, define the unreachable distance (that is, define the distance between non-adjacent nodes as infinite), and define the angle weight distance (that is, convert the local resistance of the angle into the extended resistance, and the angle into the distance between the nodes). Therefore, the shortest distance from the origin to each node and from the origin to the confluence point includes the lateral distance, the longitudinal distance and the angle weight distance, and the lateral distance and the longitudinal distance are determined by the horizontal and vertical form of the flow channels between the nodes.

[0039] Establishing the algorithm includes the following steps:

[0040] Step 1: declare an array dis to save the shortest distances from the origin to each node and from the origin to the confluence point, and declare a point set T to save the existing shortest path node set;

[0041] Step 2. Initially, the point set T only has the origin (i.e., the flow channel inlet), and dis is initialized. The initialized array dis includes the distance from the origin to itself, which is 0, and also includes the shortest distance from the origin to each node and from the origin to the confluence point; when the origin cannot reach a node, the shortest distance between the origin and the node is set to infinity;

[0042] Step 3: Select the minimum value from the array dis, which is the shortest distance corresponding to the shortest path from the origin to the corresponding node, and add the corresponding node to T;

[0043] Step 4: Determine whether the path length from the origin through the newly added node to other nodes is shorter than that from the origin directly. If so, update the array dis, that is, replace the path length from the origin directly to the node with the path length from the origin through the newly added node to other nodes. If not, keep the array dis unchanged.

[0044] Step 5. Continue to find the minimum value in dis and repeat steps 3-5 until the point set T contains all the points in the graph.

[0045] Generate flow channel: select the array dis corresponding to the smallest value of the shortest distance from all origins to confluence points, and draw a cold plate flow channel diagram including origins, confluence points, nodes and paths based on the array dis and its corresponding point set T. For multiple groups of routes with the same minimum value, select the route as the flow channel design result based on actual needs in combination with thermal simulation.

[0046] This embodiment also provides a liquid cooling plate, including a liquid inlet and a liquid outlet, wherein a cold plate flow channel is formed between the liquid inlet and the liquid outlet, and the cold plate flow channel is realized by the above-mentioned cold plate flow channel path design method.

[0047] Figure 1 A simple case is used to demonstrate the established shortest path optimization algorithm.

[0048] like Figure 1 As shown, there are four nodes A, B, C, and D, and the direct relationship and distance between the nodes have been marked;

[0049] First, create an array dis, and initialize the value to be the distance from point A to other points. The array is dis[0,20,∞,80]. Then define the point set T, and initialize the point set T to T[A].

[0050] From the array dis, we can see that the distance from B to A is the shortest, so the expanded point set T is T[A,B]. At this time, we determine whether the newly added point B can reach the previously unreachable point (point C in this case), and whether the distance from A to D is shorter than the direct distance from A (direct distance is 80, and the distance from B is 60, so the distance is updated). Fill in the shortest distance. At this time, the updated array is dis[0,20,35,60]. Then add the second shortest point C to the point set T, and get T[A,B,C].

[0051] Similarly, the array is updated to dis[0,20,35,45], and the vertex set is continued to be updated to T[A,B,C,D]; all points are in the point set T, and the array dis at this time is the shortest distance from point A to each point.

[0052] Figure 2 A typical case of cold plate flow channel design for 16 discrete heat sources is shown, including heat sources 0-15 of electronic devices, the positions of flow channel outlet 16 and flow channel inlet 17 of cold plate 18, thermal expansion plate 19 covering all heat sources, structural holes 20 and screw holes 21 of cold plate 18.

[0053] The heat source 0-15 of the electronic device transfers heat to the cold plate 18 through the heat expansion plate 19. The liquid cooling coolant enters the cold plate 18 from the flow channel inlet 17, flows out from the flow channel outlet 16 through the cold plate flow channel, and the coolant performs convection heat exchange in the cold plate flow channel to remove the heat transferred to the cold plate 18. In this embodiment, the coolant includes a single-phase liquid cooling medium (antifreeze, deionized water, etc.) and a phase change liquid cooling medium (electronic fluoride liquid, R134a, etc.).

[0054] Cold plate flow channel design method and Figure 1 The demonstration method is the same. The heat source 0 closest to the flow channel inlet is taken as the origin s0. There are 17 nodes from s0 to s16 (16 heat source points and flow channel outlets). Considering the regularity and machinability of the flow channel, and avoiding the structural hole 20 and the screw hole 21, the flow channels between the nodes are arranged in a horizontal and vertical form.

[0055] In this example, the distance between s0 and s1 is 20, the horizontal and vertical distances between s0 and s2 are 5 and 5 respectively, and the bend between the transverse channel and the longitudinal channel is converted to a distance of 2 (the local resistance loss at the bend is converted to extended resistance, and the value is determined by flow simulation), so the distance between s0 and s2 is 12; the initial point set T is T[s0], and the distance array dis[0,20,12,12,22,∞,∞,…,∞] is initialized; the array dis is continuously expanded according to the calculation method proposed above until the point set T contains all 17 nodes, Figure 3 , Figure 4 , Figure 5 and Figure 6 A schematic diagram of the flow path design of this embodiment is shown. There are multiple path design methods (4 in this example) to make the total distance from s0 to s16 the shortest.

[0056] Conduct thermal simulation design for several flow path paths with the shortest distance. Figure 7 and Figure 8 Taking path 2 as an example, the thermal simulation results of fluid and solid are shown. Figure 7 and Figure 8 In the implementation case shown, the heat consumption of a single electronic device is 30W, the coolant is R134a, and the flow rate is 80L / h. Thermal simulation analysis is performed on flow channels with different designs.

[0057] The thermal simulation results of the four flow path are shown in Table 1. The heat source temperature designed with path 2 is the lowest and the temperature uniformity is the best. The flow resistance designed with path 4 is the lowest. Select the appropriate flow path according to the needs.

[0058] Table 1

[0059] path Maximum temperature of heat source ℃ Channel pressure drop bar Difference between maximum and average temperature ℃ 1 83.90 2.20 4.07 2 83.69 2.19 3.98 3 83.90 2.19 3.98 4 84.00 2.16 4.11

[0060] The cold plate flow channel designed in this embodiment can be formed and processed by electron beam welding, and has engineering practical value.

[0061] The present invention overcomes the shortcomings of the prior art and provides a cold plate flow channel design method with an optimal path. The method combines thermal design problems with graph theory and operations research, converts the flow channel path design problem into a shortest path problem with added weights and constraints, obtains the lowest flow resistance under the premise of ensuring the heat dissipation performance of the cold plate while the flow channel passes through the heat source points of each device, and fully considers the reliability of engineering applications and the practicality of production and processing, providing a standard reference for the design of cold plate flow channels for electronic devices.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for designing a cold plate flow path, characterized in that: The specific steps include: Draw a schematic diagram of the cold plate, take the inlet and outlet of the cold plate flow channel as the origin and confluence point respectively, and mark the heat source position as the node; Establishing the algorithm includes the following steps: Step 1: declare an array dis to save the shortest distances from the origin to each node and from the origin to the confluence point, and declare a point set T to save the existing shortest path node set; Step 2: Initially, the point set T only has the origin, and dis is initialized; the initialized array dis includes the distance from the origin to itself, which is 0; it also includes the shortest distance from the origin to each node and from the origin to the confluence point; in the initial state, when the origin cannot directly reach a node, the shortest distance between the origin and the node is set to infinity; Step 3: Select the minimum value from the array dis, which is the shortest distance corresponding to the shortest path from the origin to the corresponding node, and add the corresponding node to the point set T; Step 4: Determine whether the path length from the origin through the newly added node to other nodes is shorter than that from the origin directly. If so, update the array dis, that is, replace the path length from the origin directly to the node with the path length from the origin through the newly added node to other nodes. If not, keep the array dis unchanged. Step 5: Continue to find the minimum value in dis, and repeat steps 3-5 until the point set T contains all the points in the graph; Generate flow channel: select the array dis corresponding to the smallest value of the shortest distance from all origins to confluence points, and draw a cold plate flow channel diagram including origins, confluence points, nodes and paths based on the array dis and its corresponding point set T. For multiple groups of routes with the same minimum value, select the route as the flow channel design result based on actual needs in combination with thermal simulation; The flow channels between the nodes are arranged in a horizontal and vertical form, avoiding the structural holes (20) and the screw holes (21) of the cold plate (18), and an unreachable distance and a bend angle weight distance are defined. The unreachable distance means that the distance between non-adjacent nodes is defined as infinite, and the bend angle weight distance means that the bend angle local resistance is converted into the extended resistance, and the bend angle is converted into the distance between the nodes. Therefore, the shortest distance from the origin to each node and from the origin to the confluence point includes the lateral distance, the longitudinal distance and the bend angle weight distance. The lateral distance and the longitudinal distance are determined by the flow channels between the nodes being arranged in a horizontal and vertical form.

2. A method for designing a cold plate flow path according to claim 1, characterized in that: The actual requirements include the lowest heat source temperature, the best temperature uniformity and the lowest flow resistance.

3. A liquid cooling plate, comprising a liquid inlet and a liquid outlet, wherein a cold plate flow channel is formed between the liquid inlet and the liquid outlet, characterized in that: The cold plate flow channel is realized by the design method of the cold plate flow channel path described in any one of claims 1-2.

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