Micro-channel water-cooled plate flow uniform structure and method

Abstract

The application provides a micro-channel water-cooled plate flow equalization structure, which comprises a fluid inlet of a micro-channel water-cooled plate, a flow collecting box, a rough element structure, parallel arranged micro flow channels, a flow converging box and a fluid outlet of the micro-channel water-cooled plate; the rough element structure is arranged at the rear half of the parallel arranged micro flow channels to adjust flow resistance, so that pressure drops of the front half of the flow channels are approximately equal; refrigerant enters the flow collecting box through the fluid inlet of the micro-channel water-cooled plate, flows through the rough element structure, converges in the flow converging box and is discharged from the water-cooled plate through the fluid outlet of the micro-channel water-cooled plate. The method and device improve the problem of uneven flow distribution in the micro flow channels of the micro-channel water-cooled plate and improve temperature uniformity of the water-cooled plate. The method and device introduce the rough element structure, realize flow equalization effect, enhance fluid disturbance, destroy thermal boundary layer and improve convective heat transfer effect of the water-cooled plate.

Description

Technical Field

[0001] This invention relates to the field of heat exchange device technology, and more particularly to a microchannel water-cooled plate flow equalization structure and method. Background Technology

[0002] Microchannel water-cooled plates offer advantages such as small hydraulic channel diameter and high heat exchange efficiency. The manifold and collector boxes are used for the distribution and collection of circulating refrigerant. However, due to limitations in current technology and the poor flow uniformity of the manifold itself, water-cooled plates composed of multiple parallel channels suffer from varying degrees of uneven flow distribution. When the flow rate differs within each microchannel, it leads to poor temperature uniformity in the microchannel water-cooled plate, which can significantly shorten the lifespan of the cooled components. Poor flow uniformity also hinders further improvements in the heat exchange efficiency of the water-cooled plate, greatly limiting its wider application. Summary of the Invention

[0003] To address the issues of poor flow uniformity, low temperature uniformity, and low heat exchange efficiency caused by the poor flow uniformity of microchannel water-cooled plates mentioned above, this paper presents a novel flow uniformity structure and method for microchannel water-cooled plates.

[0004] The technical means employed in this invention are as follows:

[0005] A flow equalization structure for a microchannel water-cooled plate includes: a fluid inlet for the microchannel water-cooled plate, a manifold, a rough element structure, parallel microchannels, a manifold, and a fluid outlet for the microchannel water-cooled plate.

[0006] The rear half of the parallel microchannels is provided with a rough element structure to adjust the flow resistance, so that the pressure drop in the front half of the channel is approximately equal; the refrigerant enters the manifold through the fluid inlet of the microchannel water-cooled plate, flows through the rough element structure, merges in the manifold, and is discharged from the water-cooled plate through the fluid outlet of the microchannel water-cooled plate.

[0007] The microchannel water-cooled plate has only one fluid inlet and one fluid outlet, and multiple parallel microchannels are tightly connected to the manifold and the junction box, respectively. Therefore, the total pressure drop of the fluid inlet, manifold, rough element structure, parallel microchannels, junction box, and fluid outlet of the microchannel water-cooled plate is equal, that is, equal to the pressure drop between the pressure reference lines of the inlet and outlet.

[0008] Furthermore, the present invention also includes a method for uniform flow in a microchannel water-cooled plate, comprising the following steps:

[0009] Step 1: Determine the average flow velocity at the fluid inlet of the microchannel water-cooled plate, and assume that the flow rate is evenly distributed to each parallel microchannel. Calculate the fluid velocity in the parallel microchannel under ideal flow uniformity conditions.

[0010] Step 2: Simulate using ANSYS Fluent software to calculate the pressure drop data at the inlet and outlet of each of the parallel microchannels at the flow rate obtained in Step 1, as well as the additional pressure drop generated by the rough element structure (3) at different depths.

[0011] Step 3: Determine the depth and number of the rough element structure based on the pressure drop data of the inlet and outlet obtained in Step 2; adjust the flow resistance of each channel of the water-cooled plate so that the pressure drop difference from the inlet to the center line of each of the parallel micro channels of the water-cooled plate is less than 5 Pa, so as to achieve uniform flow distribution.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] The method and apparatus described in this invention improve the problem of uneven flow distribution within the microchannels of a microchannel water-cooled plate, thereby enhancing the temperature uniformity of the water-cooled plate.

[0014] The method and apparatus described in this invention, through the introduction of a rough element structure, achieve a uniform flow effect while enhancing fluid disturbance, disrupting the thermal boundary layer, and improving the convective heat transfer effect of the water-cooled plate. Furthermore, the apparatus described in this invention features a highly efficient flow distribution structure, simple and reliable design, and a wide range of applications. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a three-dimensional schematic diagram of the microchannel water-cooled plate flow equalization structure of the present invention.

[0017] Figure 2 (a) is a schematic diagram of the fluid domain of the microchannel water-cooled plate flow uniform structure of the present invention without rough element structure.

[0018] Figure 2 (b) is a schematic diagram of the fluid domain with rough element structure of the microchannel water-cooled plate flow uniform structure of the present invention.

[0019] Figure 3 This is a rough element cross-sectional view of the microchannel water-cooled plate flow uniformity structure of the present invention.

[0020] Figure 4 This is a theoretical schematic diagram of the microchannel water-cooled plate flow equalization method of the present invention.

[0021] Wherein, 1 is the fluid inlet of the microchannel water-cooled plate, 2 is the manifold, 3 is the rough element structure, 4 is the parallel microchannels, 5 is the manifold, 6 is the fluid outlet of the microchannel water-cooled plate, 7 is the refrigerant, and 8 is the centerline. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0024] like Figures 1-4 As shown, the present invention provides a microchannel water-cooled plate flow equalization structure.

[0025] Meanwhile, as a preferred embodiment, in this application, such as Figure 2 As shown, the microchannel water-cooled plate flow equalization structure includes: a fluid inlet, a manifold, a roughening element structure, parallel microchannels, a manifold, and a fluid outlet. The first half of each microchannel has a similar structure, and under uniform flow distribution, the pressure drop in the first half of each channel is approximately equal. Conversely, by adding a roughening element structure to the second half of the channel to adjust the flow resistance, making the pressure drop in the first half of the channel approximately equal, the flow can be evenly distributed to each channel.

[0026] As a preferred implementation method, such as Figure 2As shown, the refrigerant enters the manifold through the inlet, flows through the microchannels with added rough element structures, merges in the manifold, and is discharged from the water-cooled plate through the fluid outlet.

[0027] As a preferred implementation method, such as Figure 3 As shown, the cross-sectional shape of the rough element structure at different depths can be any combination of one or more shapes such as annular, trapezoidal, elliptical, and triangular. The length, depth, and number of rough element structures added to each parallel microchannel can be different.

[0028] As a preferred implementation method, such as Figure 4 As shown, the entire microchannel water-cooled plate has only one inlet and one outlet, and each flow channel is closely connected to the manifold and junction box. Therefore, the total pressure drop of the refrigerant flowing through the inlet, manifold, each microchannel, junction box, and outlet is equal, that is, equal to the pressure drop between the pressure reference lines of the inlet and outlet.

[0029] Let the pressure drop between the inlet pressure reference line and the outlet pressure reference line be ΔP. i ΔP i It mainly consists of three parts: the pressure drop ΔP between the inlet pressure reference line and the microchannel inlet pressure reference line. flow,in,i Pressure drop ΔP of refrigerant in microchannel tube and the pressure drop ΔP between the microchannel outlet pressure reference line and the outlet pressure reference line. flow,out,i .

[0030] Pressure drop ΔP of refrigerant in microchannel tube It consists of two parts: the pressure drop ΔP between the microchannel inlet pressure reference line and the microchannel centerline. tube1,i and the pressure drop ΔP between the centerline of the microchannel and the reference pressure line at the microchannel outlet. tube2,i .

[0031] Taking flow channel [2] and flow channel [8] as examples, a detailed analysis of the pressure drop ΔP2 and ΔP8 between the refrigerant entering from the inlet pressure reference line, flowing through the second and eighth flow channels, and reaching the outlet pressure reference line reveals that:

[0032] ΔP2=ΔP flow,in,2 +ΔP tube1,2 +ΔP tube2,2 +ΔP flow,out,2 (1.1)

[0033] ΔP8=ΔP flow,in,8 +ΔP tube1,8 +ΔP tube2,8 +ΔP flow,out,8 (1.2)

[0034] Since ΔP2 = ΔP8, we can conclude that:

[0035] ΔP flow,in,2 +ΔP tube1,2 +ΔP tube2,2 +ΔP flow,out,2 =ΔP flow,in,8 +ΔP tube1,8 +ΔP tube2,8 +ΔP flow,out,8 (1.3)

[0036] When no rough element structure is added to the flow channel of a microchannel water-cooled plate, the inlet is located in the center, resulting in more refrigerant flowing through the channel closer to the center, leading to a faster flow velocity and a greater pressure drop, i.e., ΔP. tube1,2 <ΔP tube1,8 Therefore:

[0037] ΔP flow,in,2 +ΔP tube2,2 +ΔP flow,out,2 >ΔP flow,in,8 +ΔP tube2,8 +ΔP flow,out,8 (1.4)

[0038] Adding rough element structures of varying depths to the rear half of the 8th flow channel of the water-cooled plate can reduce the local resistance (ΔP) of the rear half of the 8th flow channel. tube2,8 The increase of ΔP makes both sides of inequality (1.4) approximately equal, and from formula (1.3), we can know that ΔP tube1,2 With ΔP tube1,8 They are approximately equal.

[0039] Due to ΔP tube1,2 With ΔP tube1,8 It is the pressure drop between the inlet of the micro-channel and the centerline. The structures of this part are similar. As long as the pressure drop of this part is approximately equal, it can be proved that the flow rate through each channel is approximately equal. Usually, the difference is less than 5Pa, which is considered to achieve the effect of uniform flow distribution.

[0040] As a preferred implementation method, such as Figure 2 , Figure 3 As shown, the method for determining the depth and number of rough element structures added to the latter half of the flow channel is as follows: First, determine the average working flow velocity of the water-cooled plate. Use ANSYS Fluent simulation software to simulate the actual working conditions and obtain the pressure drop of each flow channel. Find the flow channel with the smallest pressure drop, and calculate the difference between the pressure drop of the other flow channels and this difference, denoted as ΔP. n Pressure drop difference ΔP n This refers to the pressure drop introduced by using a rough element structure.

[0041] Secondly, assuming the total mass flow rate into the water-cooled plate is uniformly distributed among the various channels, the refrigerant velocity v' in each channel is calculated. Using ANSYS Fluent simulation software, simulations are performed on smooth channels and channels with different roughness element structures. Under the same conditions, the additional pressure drop introduced by the roughness element structure due to the change in depth compared to the smooth channel can be approximately calculated, denoted as ΔP. m .

[0042] Finally, based on ΔP m With ΔP n The depth and number of rough element structures are determined, thereby adjusting the flow resistance of each channel of the water-cooled plate so that the pressure drop from the inlet of each channel to the center line (8) is approximately equal.

[0043] As a preferred implementation method, such as Figure 2 As shown, the cross-sectional shape of the parallel microchannels is any one or more combinations of circles, semicircles, triangles, rectangles, ellipses, and trapezoids.

[0044] As a preferred implementation method, such as Figure 2 and Figure 4 As shown, the cross-sectional shape of the manifold along the water flow direction can be trapezoidal, rectangular, triangular, parabolic, or polygonal, but its shape and size are the same as the collection box. The cross-sectional shape of the water-cooled plate outlet can be rectangular, elliptical, or circular, and the outlet direction can be horizontal or perpendicular to the water-cooled plate, but its shape and size are the same as the fluid inlet.

[0045] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In the above embodiments of the present invention, the descriptions of each embodiment have their own emphasis; parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments. It should be understood that the disclosed technical content in the several embodiments provided in this application can be implemented in other ways.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A microchannel water-cooled plate flow equalization structure, characterized in that, include: The fluid inlet (1), manifold (2), rough element structure (3), parallel microchannels (4), manifold (5) and fluid outlet (6) of the microchannel water-cooled plate. The rough element structure (3) is provided in the rear half of the parallel microchannels (4) to adjust the flow resistance, so that the pressure drop in the front half of the channel is approximately equal; the refrigerant enters the manifold (2) through the fluid inlet (1) of the microchannel water-cooled plate, flows through the rough element structure (3), merges in the manifold (5), and is discharged from the water-cooled plate through the fluid outlet (6) of the microchannel water-cooled plate; The microchannel water-cooled plate is provided with only one fluid inlet (1) and one fluid outlet (6) of the microchannel water-cooled plate, and multiple parallel microchannels (4) are tightly connected to the manifold (2) and the junction box (5) respectively; therefore, the total pressure drop of the fluid inlet (1), manifold (2), rough element structure (3), parallel microchannels (4), junction box (5) and fluid outlet (6) of the microchannel water-cooled plate is equal, that is, equal to the pressure drop between the pressure reference lines of the inlet and outlet; the rough element structure (3) is distributed to each of the parallel microchannels (4) according to the inlet and outlet pressure drop distribution of the parallel microchannels (4).

2. The microchannel water-cooled plate flow equalization structure according to claim 1, characterized in that, The fluid inlet (1) of the microchannel water-cooled plate has a fluid inflow direction that is either horizontal or vertical to the water-cooled plate.

3. The microchannel water-cooled plate flow equalization structure according to claim 1, characterized in that, The shape and size of the junction box (5) are the same as those of the collector box (2).

4. The novel microchannel water-cooled plate flow equalization structure according to claim 1, characterized in that, The fluid outlet (6) of the microchannel water-cooled plate flows out horizontally or vertically from the water-cooled plate, and the shape and size of the opening of the fluid outlet (6) of the microchannel water-cooled plate are the same as those of the fluid inlet (1) of the microchannel water-cooled plate.

5. A method for uniform flow in a microchannel water-cooled plate, using the apparatus described in any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Determine the average flow velocity at the fluid inlet (1) of the microchannel water-cooled plate, and assume that the flow rate is evenly distributed to each parallel microchannel (4), and calculate the fluid velocity in the parallel microchannel (4) under the ideal flow uniformity condition. Step 2: Simulate using ANSYS Fluent software to calculate the pressure drop data at the inlet and outlet of each of the parallel microchannels (4) at the flow rate obtained in Step 1, as well as the additional pressure drop generated by the rough element structure (3) at different depths. Step 3: Determine the depth and number of the rough element structure (3) based on the pressure drop data of the inlet and outlet obtained in Step 2; adjust the flow resistance of each flow channel (4) of the water-cooled plate so that the pressure drop difference from the inlet to the center line (8) of each of the parallel micro-flow channels (4) of the water-cooled plate is less than 5 Pa, so as to achieve uniform flow distribution.

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