Design method of lattice porous parallel channel two-phase heat exchanger and porous rib wall structure

Abstract

The application discloses a dot-matrix porous parallel channel two-phase heat exchanger and a design method of a porous rib wall structure, and belongs to the technical field of heat dissipation. The dot-matrix porous parallel channel two-phase heat exchanger comprises a shell, the shell comprises a heated plate and a plurality of rib walls arranged on the heated plate, two adjacent rib walls and the heated plate jointly form a fluid channel, the rib wall has a plurality of first porous structures and a plurality of second porous structures arranged in a dot-matrix mode, the first porous structure has a capillary liquid suction hole, the capillary liquid suction hole is configured to guide liquid flowing through the fluid channel to flow to the heated plate, the second porous structure has a plurality of air pockets, and the air pockets of the rib wall are configured to communicate two adjacent fluid channels, so that the flow mixing effect between channels can be effectively enhanced, dryout can be delayed or inhibited, and the flow stability between channels can be improved.

Description

Technical Field

[0001] This invention relates to the field of heat dissipation technology, and in particular to a design method for a lattice-type porous parallel channel two-phase heat exchanger and a porous ribbed wall structure. Background Technology

[0002] With the rapid development of high-power-intensive devices such as chips, the trend towards higher performance is becoming increasingly apparent, leading to greater demands for heat dissipation. As the power density and heat flux density of devices continue to rise, traditional air-cooled / liquid-cooled heat exchangers struggle to simultaneously achieve high heat transfer coefficients, temperature uniformity, and low energy consumption.

[0003] Parallel microchannel two-phase heat exchangers have attracted much attention due to their excellent heat transfer capabilities. However, under harsh operating conditions with high heat flux and high gas content, a series of flow instabilities can be caused by violent flow boiling.

[0004] In related technologies, parallel microchannel two-phase heat exchangers generally suffer from problems such as increased pressure drop mismatch between channels, premature drying, and flow pattern / pressure oscillation. Summary of the Invention

[0005] The present invention aims to at least solve the technical problems existing in related technologies. To this end, the present invention proposes a lattice porous parallel channel two-phase heat exchanger, which can realize the connection between two adjacent fluid channels, enhance the flow mixing of fluids between channels, effectively delay or inhibit drying out, and improve the flow stability between channels.

[0006] This invention also proposes a design method for a porous ribbed structure.

[0007] A first aspect embodiment of the present invention provides a lattice-porous parallel channel two-phase heat exchanger comprising: a shell including a heating plate and a plurality of ribs arranged on the heating plate, wherein two adjacent ribs together enclose a fluid channel with the heating plate; the ribs having a plurality of first porous structures and a plurality of second porous structures arranged in a lattice; the first porous structures having capillary liquid suction holes configured to guide liquid flowing through the fluid channel toward the heating plate; and the second porous structures having a plurality of cavitation holes configured to connect two adjacent fluid channels.

[0008] The lattice-porous parallel-channel two-phase heat exchanger according to embodiments of the present invention has at least the following beneficial effects: the shell includes a heating plate and a plurality of ribs arranged on the heating plate, with two adjacent ribs and the heating plate jointly enclosing a fluid channel; the heating plate can serve as an element in contact with a heating device; the ribs have a plurality of first porous structures and a plurality of second porous structures distributed in a lattice; wherein, the first porous structure has capillary suction holes, and the capillary force generated by the capillary suction holes can continuously transport the liquid flowing through the fluid channel to the heating plate, thereby suppressing the heating effect. The tendency of localized drying of the hot plate can be slowed down or inhibited, improving the heat exchange efficiency between the liquid and the hot plate. The second porous structure has multiple cavities, which are configured to connect two adjacent fluid channels. This allows large or elongated bubbles in the fluid channels to be easily dispersed to other fluid channels through the cavities, thereby reducing the overall pressure drop. The liquid can be replenished laterally between two adjacent fluid channels, reducing flow pattern / pressure differences and oscillations between fluid channels. This can effectively slow down or inhibit drying, enhance boiling heat transfer, and improve the flow stability between fluid channels.

[0009] According to some embodiments of the present invention, the first porous structure is provided with a plurality of capillary liquid absorption holes, and the plurality of capillary liquid absorption holes are curved channels that are directed in multiple directions.

[0010] According to some embodiments of the present invention, in a second porous structure, multiple air cavities are multiple gas channels perpendicular to each other, the gas channels are arranged in a continuous manner, and the continuous direction of at least one gas channel is perpendicular to the length direction of the fluid channel.

[0011] According to some embodiments of the present invention, the first porous structure is a Gyroid-type porous structure;

[0012] And / or, the second porous structure is a Schwarz-P type porous structure.

[0013] According to some embodiments of the present invention, in the rib wall, a plurality of first porous structures are interconnected to form a substrate, and a plurality of second porous structures are connected within the substrate and are distributed in a lattice pattern.

[0014] And / or, the bottom wall of the fluid channel is a porous surface having a plurality of first porous structures and a plurality of second porous structures distributed in a lattice, and the cavitation of the porous surface is configured to guide the gas generated at the porous surface to flow away from the porous surface.

[0015] According to some embodiments of the present invention, the cross-sectional dimensions of the fluid channel are 2mm × 2mm;

[0016] And / or, the pore size of the capillary pores in the first porous structure is 0.08 mm to 0.15 mm;

[0017] And / or, the pore size of the cavitation in the second porous structure is 0.1mm-0.25mm;

[0018] And / or, the lattice spacing of the first porous structure and the second porous structure is 0.15mm-0.3mm;

[0019] And / or, the diameter of the capillary pores is smaller than the diameter of the cavitation pores.

[0020] The design method of the second aspect of the present invention is used to fabricate a lattice porous parallel channel two-phase heat exchanger as described in any of the first aspects; the design method of the porous ribbed wall structure includes:

[0021] Construct implicit functions of TPMS for the first and second porous structures. The implicit functions of TPMS include amplitude factors and morphological parameters.

[0022] Construct a lattice distribution function for multiple first porous structures and multiple second porous structures, such that the first porous structures and the second porous structures are lattice-distributed;

[0023] Adjust the amplitude factor and shape parameters to complete the design of the TPMS deformable surface.

[0024] According to some embodiments of the present invention, constructing a lattice distribution function for a plurality of first porous structures and a plurality of second porous structures includes:

[0025] Multiple first porous structures are interconnected to form a substrate, and multiple second porous structures are distributed within the substrate according to a lattice distribution function; with the length direction of the rib wall as the X direction and the width or thickness direction of the rib wall as the Y direction, the external dimension of the second porous structure is d, and the center distance between two adjacent second porous structures is a, then the center coordinates of the (i,j)th second porous structure are:

[0026] ;

[0027] ;

[0028] in, and Let n be the starting coordinate, and m be the number of second porous structures in the x and y directions, respectively. n = [(Ld) / a], where L is the length of the rib wall, m = [(Sd) / a], and S is the width or thickness of the rib wall.

[0029] According to some embodiments of the present invention, the design method of the porous ribbed wall structure further includes:

[0030] The deformable surface is offset by a preset distance along the two normal surfaces to obtain two offset surfaces;

[0031] By solidifying the space between two offset surfaces, a rib wall with a first porous structure and a second porous structure is obtained.

[0032] According to some embodiments of the present invention, the design method of the porous ribbed wall structure further includes:

[0033] A 3D model of a heat exchanger with a heat-receiving plate and multiple ribs is constructed. The multiple ribs are arranged and connected to the heat-receiving plate. Two adjacent ribs and the heat-receiving plate together form a fluid channel. The ribs have multiple first porous structures and multiple second porous structures, and the multiple first porous structures and multiple second porous structures are distributed in a lattice.

[0034] The 3D model of the heat exchanger is sliced ​​into multiple 2D slices, and then the multiple 2D slices are stacked together using metal 3D printing technology to obtain the solid heat exchanger.

[0035] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0037] Figure 1 This is a schematic diagram of the structure of a lattice porous parallel channel two-phase heat exchanger according to an embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram of the rib structure of a lattice porous parallel channel two-phase heat exchanger according to an embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of the first and second porous structures of the rib wall of a lattice-porous parallel channel two-phase heat exchanger according to an embodiment of the present invention, in which the lattice-distributed structure is arranged.

[0040] Figure 4 This is a schematic diagram of the first porous structure of a lattice porous parallel channel two-phase heat exchanger according to an embodiment of the present invention.

[0041] Figure 5 This is a schematic diagram of the second porous structure of a lattice porous parallel channel two-phase heat exchanger according to an embodiment of the present invention;

[0042] Figure 6 This is a flowchart illustrating a design method for a porous ribbed wall structure according to an embodiment of the present invention;

[0043] Figure 7 This is a flowchart illustrating the solidification of deformable surfaces in a design method for a porous ribbed wall structure according to an embodiment of the present invention.

[0044] Figure 8 A flowchart illustrating the 3D printing process of a design method for a porous ribbed wall structure according to an embodiment of the present invention;

[0045] Figure 9 This is a schematic diagram of the structure of a lattice porous parallel channel two-phase heat exchanger according to other embodiments of the present invention.

[0046] Icon labels:

[0047] 100. Shell; 110. Fluid passage; 111. Inlet end; 112. Outlet end; 120. Heating plate;

[0048] 200. Rib wall; 210. First porous structure; 211. Capillary pores; 220. Second porous structure; 221. Cavitation. Detailed Implementation

[0049] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0050] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0051] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0052] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0053] With the rapid development of the chip industry, the power density and heat flux density of high-power devices such as chips continue to rise (chip > Traditional air-cooled / liquid-cooled heat exchangers struggle to simultaneously achieve high heat transfer coefficients, temperature uniformity, and low energy consumption. High-power devices such as chips present the following common heat dissipation requirements:

[0054] 1. Achieve high heat dissipation and low thermal resistance within a limited volume.

[0055] 2. Suppress hot spots and temperature unevenness to improve device stability and lifespan.

[0056] 3. Low pump power / low pressure drop, resulting in high system energy efficiency.

[0057] 4. It can be mass-produced and integrated with chips / modules with high reliability.

[0058] Parallel microchannel two-phase flow heat exchangers have attracted much attention due to their superior heat transfer capabilities. However, under harsh conditions of high heat flux and high gas content, this technology can lead to a series of flow instabilities caused by intense flow boiling. These problems mainly manifest as: increased pressure drop mismatch between channels, inducing flow deviation and periodic oscillations; localized drying due to liquid film rupture and premature critical heat flux, ultimately deteriorating the temperature uniformity of the device surface and causing unstable hot spots. These phenomena severely limit the system's heat dissipation limit and long-term operational reliability. Therefore, fluid distribution and phase regulation through structural design are key to solving this problem. However, existing traditional heat transfer enhancement structures such as finned walls inherently contradict each other in synergistically maintaining the liquid wettability of the heated wall surface and promoting rapid removal of the gas core region, which limits further improvements in two-phase flow stability and overall heat transfer performance.

[0059] As an obstacle within the flow channel, the ribs increase the frictional and geometrical resistance of the fluid, resulting in a significant increase in the overall pressure drop.

[0060] Traditional solid ribs physically isolate the lateral flow of liquid film between adjacent channels. When a channel shows signs of localized drying, it is difficult to replenish effectively and "rewetting" cannot be achieved.

[0061] When flowing bubbles encounter the flow-facing side of the rib wall or at the corner formed by the rib wall and the channel wall, they are prone to stagnation, aggregation, and merging.

[0062] Related technologies propose a method for preparing a multilayer metal capillary core. By applying a pre-coating to the inner wall of a dense metal tube, the bonding force between the capillary layer and the outer metal tube is enhanced, and its axial shrinkage is slowed down, naturally forming a steam flow channel in the axial direction. However, it still has at least the following drawbacks:

[0063] (1) Deterioration of flow distribution (parallel microchannels): The coatings of different channels have different thicknesses / pores, resulting in uneven branch resistance, which leads to uneven heat load and "thermal mismatch" between channels.

[0064] (2) Local drying occurs prematurely: small holes enhance nucleation but also easily form vapor cover; if the coating is thick / the pores are poorly connected, the liquid replenishment is not timely, which leads to limited CHF increase or even decrease.

[0065] (3) Risk of peeling / powdering: Thermal cycling, thermal shock, and fluid scouring can cause stress concentration at the interface between the coating and the substrate, which can lead to coating adhesion failure and powdering.

[0066] (4) Thickness / pore size is difficult to control precisely: poor uniformity of deposition on the inner wall of the channel (port effect / masking effect), and deviation of parameters between the two side walls and the bottom wall leads to large batch / sheet dispersion and high verification cost.

[0067] (5) Manufacturing consistency and repeatability: When preparing large-area batches, it is difficult to control the pore size distribution, porosity gradient and layer thickness. The process fluctuations of interface thermal resistance and mechanical strength affect performance and lifespan.

[0068] Reference Figures 1 to 8 As shown, an embodiment of the present invention provides a lattice-type porous parallel channel two-phase heat exchanger that achieves effective control over phase change heat transfer performance through the design of a dual-hole porous structure.

[0069] Reference Figure 1 , Figure 2 and Figure 3 As shown, specifically, the shell 100 includes a heating plate 120 and a plurality of ribs 200 arranged on the heating plate 120. Two adjacent ribs 200 together with the heating plate 120 form a fluid channel 110. The fluid channel 110 has an inlet end 111 and an outlet end 112, that is, fluid can enter the fluid channel 110 from the inlet end 111 and flow out from the outlet end 112. The ribs 200 serve as at least a part of the side wall surface of the fluid channel 110. The upper surface of the heating plate 120 serves as the bottom surface of the fluid channel 110. When the fluid passes through the fluid channel 110, the heating plate 120 and the ribs 200 can come into contact with the fluid.

[0070] Reference Figure 3 , Figure 4 and Figure 5 As shown, specifically, the rib wall 200 has a plurality of first porous structures 210 and a plurality of second porous structures 220 distributed in a dot matrix. The first porous structure 210 has capillary liquid suction holes 211, which are configured to guide the liquid flowing through the fluid channel 110 to flow to the heating plate 120. The heating plate 120 can be used as an element in contact with the heating device. The capillary liquid suction holes 211 continuously deliver the liquid to the heating plate 120, which plays a role in delaying or inhibiting drying and improving the heat exchange efficiency between the liquid and the heating plate 120. Figure 2 In the example of the side wall of the rib 200, the white squares represent a first porous structure 210, and the black squares represent a second porous structure 220.

[0071] Reference Figure 3 , Figure 4 and Figure 5 As shown, the second porous structure 220 has multiple cavities 221, which can connect two adjacent fluid channels 110, allowing liquid to be laterally replenished to fluid channels 110 that are showing signs of localized drying. Large or elongated air bubbles within the fluid channels 110 can be easily dispersed to other fluid channels 110 through the cavities 221, thereby reducing the overall pressure drop.

[0072] Reference Figure 2 , Figure 4 and Figure 5 As shown, the lattice porous parallel channel two-phase heat exchanger provided in this embodiment introduces ribs 200 between adjacent fluid channels 110. The micro-nano pores of the ribs 200 provide a capillary return liquid and gas-liquid phase separation interface, which is beneficial to improving two-phase heat transfer and system stability within the fluid channels 110. Specifically, this lattice porous parallel channel two-phase heat exchanger uses a first porous structure 210 as a flow path to guide liquid to replenish the heating plate 120, and a second porous structure 220 as a flow path connecting two adjacent fluid channels 110. This reduces flow pattern / pressure differences and oscillations between channels, effectively delaying or suppressing drying, enhancing boiling heat transfer, and improving flow stability between channels.

[0073] The rib wall 200 can connect two adjacent fluid channels 110, which can reduce the overall pressure drop. When a fluid channel 110 tends to dry out locally, the liquid can be replenished laterally through the cavitation 221 to achieve "rewetting". This can reduce or avoid the stagnation, aggregation and merging of bubbles when they encounter the flow-facing surface of the rib wall 200 or at the corner formed by the rib wall 200 and the wall of the fluid channel 110.

[0074] Reference Figure 3 , Figure 4 and Figure 5 As shown, it is understandable that traditional heat exchangers suffer from the defect of excessive and rapid generation of steam bubbles on the heated wall, which merge together to form a steam film that isolates the liquid from the heated wall. Due to the presence of this steam film, the liquid can no longer contact the heated wall. Without the cooling effect of the liquid, the wall temperature rises sharply, resulting in premature drying.

[0075] Reference Figure 3 , Figure 4 and Figure 5 As shown, specifically, the first porous structure 210 of the lattice porous parallel channel two-phase heat exchanger has multiple capillary liquid suction holes 211. The multiple capillary liquid suction holes 211 are curved channels that are open in multiple directions, which facilitates the liquid to penetrate into the heating plate 120 from various directions and prevents the heating plate 120 from drying out on the inner wall surface of the fluid channel 110, thereby improving the heat dissipation efficiency of the lattice porous parallel channel two-phase heat exchanger.

[0076] Reference Figure 3 , Figure 4 and Figure 5 As shown, specifically, in the second porous structure 220 of the lattice porous parallel channel two-phase heat exchanger, multiple air cavities 221 are multiple gas channels that are perpendicular to each other. The gas channels are arranged in a continuous manner, and the length direction of at least one of the gas channels is perpendicular to one of the inner wall surfaces of the fluid channel 110. This facilitates the connection between two adjacent fluid channels 110, effectively reduces the overall pressure drop of the lattice porous parallel channel two-phase heat exchanger, disperses the bubbles, and improves the phase change heat transfer efficiency.

[0077] Reference Figure 3 , Figure 4 and Figure 5 As shown, it can be understood that the first porous structure 210 is a Gyroid-type porous structure and the second porous structure 220 is a Schwarz-P-type porous structure.

[0078] Reference Figure 3 , Figure 4 and Figure 5 As shown, the Triple Periodic Minimal Surface (TPMS) was first proposed by the German mathematician Hermann Schwarz in 1865. The TPMS structure has an average curvature of 0, a continuous and smooth surface, and a large specific surface area; simultaneously, its internal structure is interconnected in multiple directions, resulting in high permeability. Therefore, applying the TPMS structure to microchannel flow boiling research can not only provide a larger heat transfer area but also regulate the permeability of the gas and liquid phases by changing the pore size, promoting the detachment of nucleated bubbles and the wetting of the surface by the liquid, enhancing the orderliness of the gas-liquid two-phase behavior. This allows the lattice porous parallel channel two-phase heat exchanger to achieve high-flux heat dissipation and low thermal resistance within a limited volume.

[0079] Reference Figure 3 , Figure 4 and Figure 5 As shown, according to the analysis of permeability theory, the permeability of liquids is significantly affected by pore connectivity and viscosity, while the permeability of gases is more sensitive to pore size.

[0080] Reference Figure 3 , Figure 4 and Figure 5As shown, considering the different behavior characteristics of the gas and liquid phases during nucleated boiling in microchannels, this lattice porous parallel channel two-phase heat exchanger uses Gyroid-type porous structures as the flow path guiding the liquid to replenish the heating plate 120, and Schwarz-P type pores as the flow path for gas communication and dispersion. The Gyroid-type pore structure has tortuous channels in multiple directions, which facilitates the liquid to penetrate into the inner wall of the heating plate 120 from various directions, preventing the surface of the inner wall of the heating plate 120 from drying out. The Schwarz-P type porous structure has three mutually perpendicular straight channels, which is conducive to the dispersion of large bubbles or elongated bubbles, thereby reducing the overall pressure drop. The liquid can be laterally replenished between two adjacent fluid channels 110, reducing flow pattern / pressure differences and oscillations between channels.

[0081] Reference Figure 3 , Figure 4 and Figure 5 As shown, it is understandable that in boiling microfluidics, the random generation and growth of bubbles can lead to violent fluctuations in local pressure, causing flow pattern oscillations and flow reversals, which severely interfere with the liquid supply and bubble detachment process, resulting in unstable heat transfer and temperature fluctuations.

[0082] In the lattice porous parallel channel two-phase heat exchanger provided in this embodiment of the invention, multiple first porous structures 210 are interconnected in the rib wall 200 to form a substrate, and multiple second porous structures 220 are connected in the substrate and are distributed in a lattice. The multiple first porous structures 210 and multiple second porous structures 220 are interconnected, and at least some capillary liquid absorption holes 211 are connected to some air cavities 221.

[0083] Reference Figure 3 , Figure 4 and Figure 5 As shown, multiple first porous structures 210 form a near-wall layer, while multiple second porous structures 220 form a core layer. The near-wall layer is arranged around the core layer. The near-wall layer is biased towards liquid phase permeation and replenishment, while the core layer facilitates gas connectivity and dispersion, thereby reducing interface competition, reducing flow pattern / pressure differences and oscillations between channels, and improving heat transfer stability.

[0084] Reference Figure 2 , Figure 4 and Figure 5 As shown, the first porous structure 210 and the second porous structure 220 are constructed and combined within the rib wall 200 to form a "parallel heat conduction network", which diffuses the heat from hot spots, reduces the temperature standard deviation, suppresses hot spots and temperature unevenness, and improves the stability and lifespan of the device.

[0085] Reference Figure 2 , Figure 4 and Figure 5As shown, in addition, this lattice porous parallel channel two-phase heat exchanger can adjust the density and distribution uniformity of the vaporization core by changing the size parameters and lattice distribution parameters of the first porous structure 210 and the second porous structure 220, thereby improving the uniformity of the phase change gas content between channels.

[0086] Reference Figure 9 As shown, it should be understood that in some other embodiments, the surface of the heating plate 120 facing the rib wall 200 is a porous surface, that is, the bottom wall of the fluid channel 110 is a porous surface. The porous surface has a first porous structure 210 and a plurality of second porous structures 220 distributed in a lattice. The first porous structure 210 has capillary liquid suction holes 211, which are configured to guide the liquid flowing through the fluid channel 110 to flow toward the heating plate 120. The cavitation 221 of the porous surface is configured to guide the gas generated at the porous surface to flow away from the porous surface, so as to separate the gas exit path and the liquid replenishment path, and further improve the heat exchange efficiency and system stability of the lattice porous parallel channel two-phase heat exchanger.

[0087] Reference Figure 2 , Figure 4 and Figure 5 As shown, it can be understood that in this embodiment, the cross-sectional dimensions of the fluid channel 110 are 2mm × 2mm; the pore diameter of the capillary suction pores 211 of the first porous structure 210 is 0.08mm-0.15mm; the pore diameter of the air cavities 221 of the second porous structure 220 is 0.1mm-0.25mm; and the spacing between the lattice distribution of the first porous structure 210 and the second porous structure 220 is 0.015mm-0.3mm. The pore diameter of the capillary suction pores 211 is smaller than the pore diameter of the air cavities 221.

[0088] Reference Figure 2 , Figure 4 and Figure 5 As shown, specifically, the lattice porous parallel channel two-phase heat exchanger can be formed by metal 3D printing (e.g., electrochemical 3D printing) to create the structure of shell 100 and rib wall 200, thereby completing the precise and efficient design of the complex dual-pore porous structure and realizing the regulation of phase change heat transfer performance by the dual-pore porous structure.

[0089] Reference Figure 2 , Figure 4 and Figure 5 As shown, this lattice porous parallel channel two-phase heat exchanger is designed based on the parameter-driven design of TPMS (Triple Period Minimal Surface) trigonometric functions. By changing the amplitude factor and morphological parameters in the TPMS trigonometric function parameter expression, the design of the TPMS deformable pore unit is completed, thereby realizing the geometric morphological change of the porous structure.

[0090] Reference Figure 2, Figure 4 and Figure 5 As shown, the lattice porous parallel channel two-phase heat exchanger can be constructed by electrochemical 3D printing on the fluid channel 110 to build ribs 200. The three-dimensional model data is imported into the 3D printing equipment, and the fine fluid channels 110 with different ribs 200 are printed according to the model surface data description, thereby obtaining the heat exchanger.

[0091] Reference Figures 6-8 As shown, the present invention provides a design method for a porous ribbed wall structure, used for designing and manufacturing a lattice porous parallel channel two-phase heat exchanger as shown in any of the above embodiments. The design method for the porous ribbed wall structure includes the following steps:

[0092] Step S100: Construct TPMS implicit function expressions for the first porous structure 210 and the second porous structure 220. The TPMS implicit function expressions include amplitude factors and morphological parameters.

[0093] Step S200: Construct a lattice distribution function for the plurality of first porous structures 210 and the plurality of second porous structures 220, so that the first porous structures 210 and the second porous structures 220 are lattice distributed.

[0094] Step S300: Adjust the amplitude factor and shape parameters to complete the design of the TPMS deformable surface.

[0095] Reference Figure 2 and Figure 6 As shown, in step S100, specifically, the first porous structure 210 is a Gyroid-type porous structure, while the second porous structure 220 is a Schwarz-P-type porous structure. The TPMS structure, applied to microchannel flow boiling research, not only provides a larger heat transfer area but also allows for the regulation of gas and liquid phase permeability by altering pore size, promoting the dispersion of nucleated bubbles, liquid wetting of surfaces, and enhancing the orderliness of the gas-liquid two-phase behavior.

[0096] Reference Figure 2 and Figure 6 As shown, the shape of the TPMS structure is strictly controlled by implicit functional equations containing trigonometric functions. The governing equations for the Gyroid-type and Schwarz-P-type pore structures are as follows:

[0097] ;

[0098] ;

[0099] Reference Figure 2 and Figure 6 As shown, in the above implicit function equation, d, e, f, g, h, and i are all amplitude factors, while t is a morphological parameter.

[0100] Reference Figure 2 and Figure 6 As shown, the first porous structure 210 is a Gyroid-type porous structure that facilitates liquid permeation and flow. The second porous structure 220, which is a Schwarz-P type porous structure, facilitates bubble separation and connectivity through a lattice distribution. This separates the bubble detachment path and the liquid return path during phase change heat transfer, thereby simultaneously meeting the requirements of different behavior characteristics of the vapor and liquid phases during phase change on the channel surface. This achieves precise control and phase change-enhanced heat transfer effect of the micro-channel dual-pore porous structure.

[0101] In step S200, the design method of the porous ribbed structure can construct a lattice distribution function of multiple first porous structures 210 and multiple second porous structures 220 so that the multiple first porous structures 210 and multiple second porous structures 220 are lattice distributed.

[0102] Reference Figure 2 and Figure 6 As shown, in step S300, the design method for the porous ribbed structure proposes a mathematical function based on the Triply Periodic Minimal Surface (TPMS) to drive the design of the lattice porous parallel channel two-phase heat exchanger mentioned in the above embodiment. By adjusting the amplitude factor and morphological parameters, it is possible to accurately and efficiently construct pore structures of different shapes and sizes in the first porous structure 210 and the second porous structure 220, construct the quantitative relationship between the porous structure characteristics and the TPMS function expression, and obtain the influence law of the TPMS-based Gyroid type and Schwarz-P type pore structures on the liquid permeation process.

[0103] Reference Figure 2 and Figure 6 As shown, the TPMS structure has the characteristics of suitable pore size, large specific surface area, high permeability and smooth flow channel. The design method of this porous ribbed structure can control the geometric morphological characteristics of the first porous structure 210 and the second porous structure 220 by adjusting the amplitude factor and morphological parameters. Through the design of the dual-pore porous structure, the phase change heat transfer performance can be effectively controlled.

[0104] Understandably, the design method for this porous ribbed structure includes the following steps in step S200: Constructing the lattice distribution function for the plurality of first porous structures 210 and the plurality of second porous structures 220:

[0105] Multiple first porous structures 210 are interconnected to form a substrate, and multiple second porous structures 220 are distributed within the substrate according to a lattice distribution function; taking the length direction of the rib wall 200 as the X direction, the width direction or thickness direction of the rib wall 200 as the Y direction, the external dimension of the second porous structure 220 as d, and the center distance between two adjacent second porous structures 220 as a, then the center coordinates of the (i,j)th second porous structure 220 are:

[0106] ;

[0107] ;

[0108] in, and Let n be the starting coordinate, and m be the number of the second porous structures 220 in the x and y directions, respectively. n = [(Ld) / a], where L is the length of the rib wall 200, and m = [(Sd) / a], where S is the width or thickness of the rib wall 200.

[0109] The lattice distribution of the first porous structure 210 and the second porous structure 220 has the following advantages:

[0110] (1) Precise control of flow path: The "lattice" ensures the regular arrangement of the first porous structure 210 and the second porous structure 220, and the path through which the fluid passes can be preset to construct the replenishment channel of liquid and the dispersion channel of gas.

[0111] (2) Increase surface area: Ordinary porous structures (such as particle sintered porous metals) have uneven pore distribution and a large number of closed pores or blind pores. However, the "lattice distribution" combined with the characteristics of "TPMS dual pores" can create a higher specific surface area within a given volume or surface area. A larger surface area usually means more efficient heat transfer or mass transfer.

[0112] (3) Avoid dead zones and blockages: The continuous and interconnected pores of the TPMS structure combined with the regular lattice distribution can prevent fluid from stagnating in certain areas and forming dead zones, or from excessive accumulation in certain areas leading to blockages.

[0113] (4) Based on regularity, it increases the flexibility of design and adaptability to complex geometry, and can optimize heat transfer, mass transfer, fluid dynamics and other performance by precisely controlling pore structure parameters and lattice distribution parameters.

[0114] Reference Figure 2 and Figure 7 As shown, it is understandable that the design method for porous ribbed structures also includes the following steps:

[0115] Step S400: Offset the deformed surface along the two normal surfaces by a preset distance to obtain two offset surfaces;

[0116] In step S500, the space between the two offset surfaces is solidified to obtain a rib 200 with a first porous structure 210 and a second porous structure 220.

[0117] Reference Figure 3 , Figure 4 and Figure 7 As shown, in steps S400 and S500, after the TPMS deformable surface design is completed for the lattice porous parallel channel two-phase heat exchanger, the obtained deformable surface can be offset by a preset distance along two normal surfaces to obtain two offset surfaces. By solidifying the space between the two offset surfaces, the construction of the first porous structure 210 and the second porous structure 220 can be completed, so that the rib wall 200 has two porous structures: the first porous structure 210 and the second porous structure 220.

[0118] Reference Figure 3 , Figure 4 and Figure 7 As shown, it should be noted that the spatial solidification between the two offset surfaces can be achieved using the nTopology software. The preset distance can be adjusted according to actual design requirements, which will not be elaborated here.

[0119] Reference Figure 1 , Figure 2 and Figure 8 As shown, it is understandable that the design method for porous ribbed structures also includes the following steps:

[0120] Step S600: Construct a 3D model of a heat exchanger having a heat-receiving plate 120 and multiple ribs 200. The multiple ribs 200 are arranged and connected to the heat-receiving plate 120. Two adjacent ribs 200 and the heat-receiving plate 120 together enclose a fluid channel 110. The ribs 200 have multiple first porous structures 210 and multiple second porous structures 220, and the multiple first porous structures 210 and multiple second porous structures 220 are distributed in a lattice.

[0121] Step S700: The heat exchanger 3D model is sliced ​​into multiple 2D slices, and the multiple 2D slices are stacked solid using metal 3D printing technology to obtain the heat exchanger solid.

[0122] Reference Figure 1 , Figure 2 and Figure 8As shown, the design method of the porous ribbed structure can construct a heat exchanger 3D model containing the first porous structure 210 and the second porous structure 220 based on the obtained first porous structure 210 and second porous structure 220. The heat exchanger 3D model is sliced ​​into several layers of 2D slices by 3D printing (additive manufacturing). The raw materials are directly and precisely prepared layer by layer by using electrochemical 3D printing technology to obtain the heat exchanger entity.

[0123] Currently, porous ribbed wall structures are designed and manufactured using electrochemical 3D printing technology. The processing precision of electrochemical 3D printing can typically reach the micrometer or even submicrometer level. Subsequent parameter optimization can then enable the precise manufacturing and control of lattice porous parallel channel two-phase heat exchangers. Therefore, this porous ribbed wall structure design method is feasible for the integrated and precise manufacturing of lattice porous parallel channel two-phase heat exchangers.

[0124] It should be understood that, in some other embodiments, the design method of this porous ribbed structure can also manufacture lattice porous parallel channel two-phase heat exchangers by means of selective laser melting, laser / electron beam energy deposition, etc.

[0125] Reference Figure 1 , Figure 2 and Figure 8 As shown, it can be understood that in this embodiment, the design method of the porous ribbed structure changes the size and distribution parameters of the Schwarz-P type and Gyroid type pores to meet the differentiated requirements of the gas-liquid two-phase dynamics behavior involved in bubble nucleation and two-phase flow between channels on the capillary permeability performance of the porous medium, thereby achieving the regulation of two-phase behavior.

[0126] According to Hsu's activated cavity theory, the size range within which surface pores can serve as activated nuclei is:

[0127] ;

[0128] Where δ is the thermal boundary layer thickness, T_w is the wall temperature, T_s is the saturation temperature, T_∞ is the mainstream liquid temperature, C_1 and C_2 are empirical constants, σ ​​is the liquid surface tension, h_f is the latent heat of vaporization of the liquid, and p_v is the saturated vapor density.

[0129] As shown in the above equation, under given conditions, only pores within a certain size range can be activated to become vaporization nuclei. Furthermore, within the activation conditions, the larger the pore size, the lower the wall superheat required for bubble growth. Therefore, the design method of this porous ribbed wall structure, which precisely modifies the pore structure and size to control the vaporization nuclei, is feasible.

[0130] In addition, the Schwarz-P type pores have an inward expansion characteristic, which can reduce the cooling effect of external supercooled fluid on the gas nuclei, protect the growth of bubbles, and thus facilitate nucleation.

[0131] According to Young-Laplace capillary theory, the capillary pressure of porous materials is:

[0132] ;

[0133] Where ΔP is the capillary pressure generated by the porous material, σ is the surface tension of the liquid, θ is the contact angle of the liquid on the solid surface, and d_p is the characteristic pore size of the porous material.

[0134] As can be seen from the above, capillary pressure is inversely proportional to pore size. That is, the smaller the pore size, the greater the capillary pressure, which is more conducive to the absorption of liquid by porous materials, thereby maintaining surface wettability.

[0135] According to Darcy's Law, the flow resistance of a liquid in a porous material is:

[0136] ;

[0137] Where ΔP_vis is the viscous pressure drop (flow resistance), μ is the dynamic viscosity of the liquid, δ is the thickness of the porous medium in the flow direction, L is the actual flow path length of the liquid in the pores, v is the apparent flow velocity of the liquid, C_v is a dimensionless constant (shape factor) related to the pore tortuosity and shape, ε is the porosity of the porous medium, and d_p is the characteristic pore size (or particle diameter) of the porous material.

[0138] As can be seen from the above formula, the resistance to liquid flow is inversely proportional to the square of the orifice diameter, which means that the smaller the orifice diameter, the less favorable it is for fluid flow.

[0139] It is evident that the capillary action and permeation of porous media on liquids are mutually influential, and it is necessary to find the balance point of capillary permeation. This is also the significance of the design method of this porous ribbed structure, which controls the density and distribution uniformity of vaporization nuclei by changing the amplitude factor and morphological parameters.

[0140] Similarly, Darcy's law can be used to obtain the mass flow rate of gas passing through a porous medium:

[0141] ;

[0142] Where m is the gas mass flow rate through the porous medium, ρ_v is the gas (vapor) density, σ is the liquid surface tension, μ_v is the dynamic viscosity of the gas (vapor), ε is the porosity of the porous medium, d_p is the characteristic pore size of the porous material, and δ is the thickness of the porous medium (the length through which the gas flows).

[0143] As shown in the above equation, the gas escape mass flow rate is directly proportional to the cube of the pore size, meaning that the larger the pore size of the porous medium, the more favorable it is for gas escape. Furthermore, the capillary effect on the liquid is also considered under high gas content conditions, providing a theoretical basis for the control research of lattice porous parallel channel two-phase heat exchangers.

[0144] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A lattice-type porous parallel channel two-phase heat exchanger, characterized in that, include: The shell includes a heating plate and a plurality of ribs arranged on the heating plate. Two adjacent ribs together enclose the heating plate to form a fluid channel. The ribs have a plurality of first porous structures and a plurality of second porous structures distributed in a lattice. The first porous structures have capillary liquid suction holes configured to guide liquid flowing through the fluid channel toward the heating plate. The second porous structures have a plurality of air cavities, and the air cavities of the ribs are configured to connect two adjacent fluid channels. The first porous structure is a Gyroid-type porous structure; the second porous structure is a Schwarz-P-type porous structure. In the rib wall, a plurality of first porous structures are interconnected to form a substrate, and a plurality of second porous structures are connected within the substrate and are distributed in a lattice pattern; the bottom wall of the fluid channel is a porous surface, the porous surface having a plurality of first porous structures and a plurality of second porous structures distributed in a lattice pattern, and the cavitation of the porous surface is configured to guide the gas generated at the porous surface to flow away from the porous surface.

2. The lattice porous parallel channel two-phase heat exchanger according to claim 1, characterized in that, The first porous structure is provided with a plurality of capillary liquid absorption holes, and the plurality of capillary liquid absorption holes are curved channels that open in multiple directions.

3. The lattice porous parallel channel two-phase heat exchanger according to claim 1, characterized in that, In one of the second porous structures, the plurality of air cavities are multiple gas channels perpendicular to each other, the gas channels are arranged in a continuous manner, and the continuous direction of at least one of the gas channels is perpendicular to the length direction of the fluid channel.

4. The lattice porous parallel channel two-phase heat exchanger according to claim 1, characterized in that, The cross-sectional dimensions of the fluid channel are 2mm × 2mm; And / or, the pore size of the capillary pores in the first porous structure is 0.08 mm to 0.15 mm; And / or, the pore size of the cavitation in the second porous structure is 0.1mm-0.25mm; And / or, the lattice spacing of the first porous structure and the second porous structure is 0.15mm-0.3mm; And / or, the diameter of the capillary pore is smaller than the diameter of the cavitation.

5. A design method for a porous ribbed wall structure, characterized in that, Used to manufacture the lattice porous parallel channel two-phase heat exchanger as described in any one of claims 1 to 4; The design method for the porous ribbed wall structure includes: Construct a TPMS implicit function expression for the first porous structure and the second porous structure, wherein the TPMS implicit function expression includes an amplitude factor and a morphological parameter; Construct a lattice distribution function for multiple first porous structures and multiple second porous structures, such that the first porous structures and the second porous structures are lattice-distributed; Adjust the amplitude factor and the shape parameters to complete the design of the TPMS deformable surface.

6. The design method for the porous ribbed wall structure according to claim 5, characterized in that, The construction of the lattice distribution function for the plurality of first porous structures and the plurality of second porous structures includes: Multiple first porous structures are interconnected to form a substrate, and multiple second porous structures are distributed within the substrate according to the lattice distribution function; taking the length direction of the rib wall as the X direction, the width direction or thickness direction of the rib wall as the Y direction, the external dimension of the second porous structure as d, and the center distance between two adjacent second porous structures as a, then the center coordinates of the (i,j)th second porous structure are: ； ； in, and Let n be the starting coordinate, and m be the number of the second porous structures in the x and y directions, respectively. n = [(Ld) / a], where L is the length of the rib wall, m = [(Sd) / a], and S is the width or thickness of the rib wall.

7. The design method for the porous ribbed wall structure according to claim 6, characterized in that, The design method for the porous ribbed wall structure also includes: The deformed surface is offset by a preset distance along the two normal surfaces to obtain two offset surfaces; The rib wall having the first porous structure and the second porous structure is obtained by solidifying the space between the two offset surfaces.

8. The design method of the porous ribbed wall structure according to claim 7, characterized in that, The design method for the porous ribbed wall structure also includes: A 3D model of a heat exchanger with a heating plate and multiple ribs is constructed. The multiple ribs are arranged in a row and connected to the heating plate. Two adjacent ribs and the heating plate together form a fluid channel. The ribs have multiple first porous structures and multiple second porous structures, and the multiple first porous structures and multiple second porous structures are distributed in a lattice. The heat exchanger 3D model is sliced ​​into multiple 2D slices, and the multiple 2D slices are stacked together using metal 3D printing technology to obtain the heat exchanger solid.

Images