Porous structure evaporator for loop heat pipe

Abstract

The present invention relates to an evaporator (100) for a loop heat pipe (300). The evaporator (100) includes a first porous structure (110) and a second porous structure (112) disposed on a substrate (120). The evaporator (100) also includes a housing (140) surrounding the first porous structure (110) and the second porous structure (112) to form a first chamber (150) and a second chamber (152) separated by the first porous structure (110) and the housing (140). The first chamber (150) is coupled to a condenser (200) via an input port (160) and is used to receive cooling fluid (F) from the condenser (200). The second chamber (152) is coupled to the condenser (200) via an output port (162) and is used to supply the cooling fluid (F) to the condenser (200). Furthermore, the present invention also relates to a loop heat pipe (300) comprising an evaporator (100) according to an embodiment of the present invention.

Description

Technical Field

[0001] This invention relates to an evaporator for a loop heat pipe and a loop heat pipe including the evaporator. Background Technology

[0002] Loop heat pipe (LHP) technology is a two-phase heat dissipation technology based on liquid-gas phase change, providing high heat transfer efficiency without the need for active equipment such as pumps. An LHP typically consists of an evaporator, condenser, steam pipes, liquid pipes, and a cooling fluid circulating along the loop during operation. LHP effectively transfers heat loads, meaning the temperature difference between the heat source and heat dissipation areas is minimal. More specifically, LHP can achieve thermally efficient operation even under anti-gravity conditions, i.e., when the LHP evaporator is positioned above the LHP condenser.

[0003] The LHP evaporator is a precision device designed to transfer heat flux energy from the heated area to the dissipating area by changing the cooling fluid from a liquid phase to a gas phase. The LHP evaporator draws the liquid working fluid into the evaporation zone through a meniscus formed in a porous structure, or capillary wick, causing the liquid cooling fluid to accumulate and ensuring a pressure difference between the accumulated cooling fluid and the generated steam. The accumulated cooling fluid is stored in the liquid phase or located within the pores.

[0004] Typically, an LHP evaporator consists of a shell, a substrate, a capillary wick, a compensation chamber, and a vapor collector. LHP evaporators can be cylindrical or flat. For electronic cooling in information and communication technology (ICT) applications, flat LHP evaporators are preferred because they have a flat surface that allows direct contact with electronic components such as chips or application-specific integrated circuits (ASICs). Summary of the Invention

[0005] One objective of this invention is to provide a solution that reduces or solves the drawbacks and problems of conventional solutions.

[0006] Another objective of this invention is to provide an evaporator for LHP that has improved heat transfer efficiency compared to conventional solutions.

[0007] The above and other objectives are achieved through the content of the independent claims. Other embodiments of the invention can be found in the dependent claims.

[0008] According to a first aspect of the invention, the above and other objectives are achieved by an evaporator for a loop heat pipe, said evaporator comprising: The first porous structure and the second porous structure are both disposed on the first side of the substrate and extend outward from the first side; An electronic heat source is disposed on the second side of the substrate; A housing that surrounds the first porous structure and the second porous structure to form a first chamber and a second chamber separated by the first porous structure and the housing; wherein, The first chamber is coupled to the condenser via an input port and is used to receive cooling fluid from the condenser. The second chamber is coupled to the condenser via an output port and is used to supply the cooling fluid to the condenser.

[0009] The porous structure can also be represented as a capillary core structure or a capillary structure.

[0010] The advantages of the evaporator described in the first aspect are that it can reduce the pressure loss of the liquid cooling fluid flowing through the first and second porous structures, and has the potential to saturate the volume of the second porous structure in front of the heat source region. Therefore, cooling performance is improved compared to conventional solutions.

[0011] In one implementation of the evaporator according to the first aspect, The first chamber is used to receive liquid cooling fluid. The second chamber is used to supply vapor-phase cooling fluid.

[0012] In one implementation of the evaporator according to the first aspect, the second chamber is used to receive gaseous cooling fluid from the first chamber through a first porous structure.

[0013] The advantage of this approach is that the first porous structure can be implemented with a reduced height or at an even lower height, thus providing a slim evaporator assembly, which is an important parameter for electronic cooling applications.

[0014] In one implementation of the evaporator according to the first aspect, The first chamber is defined by the first side of the substrate, the first porous structure, and the housing. The second chamber is defined by the first porous structure, the second porous structure, and the shell.

[0015] The advantage of this approach is that the cooling fluid inlet and outlet connectors can be designed with greater freedom, for example, aligned on the same face / side of the evaporator housing, or on opposite faces, or on adjacent faces, adapting to application design constraints.

[0016] In one implementation of the evaporator according to the first aspect, the first side of the substrate is disposed opposite to the second side of the substrate.

[0017] In one implementation of the evaporator according to the first aspect, the electronic heat source is aligned with the second porous structure.

[0018] The advantage of this approach is that the heat source is limited in the first chamber, allowing more heat flux to directly enter the evaporation process, while less heat flux leaks into the first chamber. This enhances the thermal performance of the evaporator.

[0019] In one implementation of the evaporator according to the first aspect, the first porous structure includes a first pore diameter within a first range, and the second porous structure includes a second pore diameter within a second range, wherein the first pore diameter is smaller than the second pore diameter.

[0020] The advantages of this implementation are: the first porous structure prevents vapor accumulated in the second chamber from reaching or entering the first chamber, thereby providing the necessary pressure difference between the two chambers during cooling operation. Furthermore, the second porous structure provides reduced pressure loss for coolant flow, allowing the coolant to diffuse along the heat source area / surface for improved cooling.

[0021] In one implementation of the evaporator according to the first aspect, the first range includes an aperture of less than 10 micrometers, and the second range includes an aperture of greater than 10 micrometers.

[0022] The advantage of this implementation is that it provides an effective meniscus on the surface of the first porous structure, which contacts the gas phase in the second chamber to provide the necessary capillary pressure.

[0023] In one implementation of the evaporator according to the first aspect, the second range includes an aperture greater than 40 micrometers.

[0024] The advantage of this implementation is that the second porous structure has sufficient capillary force, defined by the meniscus formed in its pores, to draw in coolant flow from the first chamber through the first porous structure and diffuse the coolant flow along the second porous structure for thermally efficient evaporation under heat load.

[0025] In one implementation of the evaporator according to the first aspect, the first range includes an pore size greater than 0.5 micrometers, and the second range includes an pore size less than 100 micrometers.

[0026] The advantage of this approach is that there are sufficiently large pores in the second porous structure, which facilitates the escape of vapor / gas generated from the liquid cooling fluid stored in the pores of the second porous structure.

[0027] In one implementation of the evaporator according to the first aspect, the second porous structure includes a plurality of second porous segments with different pore size ranges.

[0028] In one implementation of the evaporator according to the first aspect, the plurality of second porous segments are arranged toward the centerline of the substrate with increasing apertures.

[0029] The advantage of this approach is that it can balance the pressure loss of the coolant flow through the second porous structure, while providing a smaller meniscus in the evaporation zone / surface, thereby providing higher capillary force / pressure to draw in coolant for further evaporation.

[0030] In one implementation of the evaporator according to the first aspect, The first porous structure extends outward at a first height. The second porous structure extends outward at a second height, which is less than the first height.

[0031] The advantage of this approach is that both the first and second chambers are located on the same horizontal plane, resulting in a lower overall height and thus enabling a slim and compact design, which may be an important parameter for electronic cooling applications.

[0032] In one implementation of the evaporator according to the first aspect, the first porous structure and the second porous structure extend in the outward direction at a uniform height.

[0033] In one implementation of the evaporator according to the first aspect, The first porous structure extends outward at a uniform height. The second porous structure extends outward at an uneven height.

[0034] The advantages of this approach are: it supports pressure loss balance, which helps reduce the total pressure loss of coolant flowing through the first porous structure, while providing smaller pores to create smaller menisci in some heat load areas, thereby helping to improve the capillary pressure generated by the second porous structure.

[0035] In an implementation of the evaporator according to the first aspect, the substrate includes a first substrate segment having a first thermal conductivity and a second substrate segment having a second thermal conductivity greater than the first thermal conductivity.

[0036] The advantage of this implementation is that it prevents heat flux from leaking through the substrate into the first chamber when a heat load is applied. Therefore, the cooling fluid does not need to be subcooled to a greater extent at the inlet of the evaporator and the inlet of the first chamber, thereby increasing the total heat flux reaching the second porous structure where the cooling fluid evaporates.

[0037] In the implementation of the evaporator according to the first aspect, the first substrate segment supports the first porous structure, and the second substrate segment supports the second porous structure and the first chamber.

[0038] The advantage of this implementation is that when a heat load is applied, it further prevents heat flux from leaking into the first chamber through the substrate and the second porous structure.

[0039] In one implementation of the evaporator according to the first aspect, the evaporator further includes a heat insulation layer disposed between the first porous structure and the substrate.

[0040] The advantages of this implementation are: it prevents heat flux from leaking into the first chamber through the substrate, thereby improving the overall thermal efficiency of the evaporator. Furthermore, due to the high thermal conductivity of the middle portion of the bottom substrate, the thermal resistance is reduced through the solid substrate body located between the heat-loaded surface and the second porous structure.

[0041] In one implementation of the evaporator according to the first aspect, the insulation layer extends from the first porous structure to the wall of the housing or at least partially extends into the wall.

[0042] The advantage of this implementation is that it provides more control to prevent or reduce heat flux leakage to the first chamber through the substrate, while maximizing the heat flux flowing to the second porous structure, where the cooling fluid is converted into steam during evaporation.

[0043] In one implementation of the evaporator according to the first aspect, the first chamber is used to receive the cooling fluid from the condenser via one or more microchannels disposed within the first porous structure.

[0044] The advantage of this implementation is that it improves the saturation capacity of the first porous structure because the first porous structure has smaller pores and the coolant flow must overcome a larger pressure gradient to flow through the first porous structure.

[0045] According to a second aspect of the invention, the above and other objects are achieved by a loop heat pipe comprising an evaporator according to any implementation thereof and a condenser coupled to the evaporator via the input port and the output port.

[0046] Other applications and advantages of embodiments of the present invention will become apparent from the following detailed description. Attached Figure Description

[0047] The accompanying drawings are intended to illustrate and explain different embodiments of the invention, in which: Figures 1a to 1c Different views of an evaporator for a loop heat pipe according to an embodiment of the present invention are shown; Figure 2 Figures 5 to 6 illustrate different aspects of an evaporator according to an embodiment of the present invention; Figure 6a and Figure 6b A loop heat pipe according to an embodiment of the present invention is shown; Figure 7 A loop heat pipe according to another embodiment of the present invention is shown. Detailed Implementation

[0048] Traditionally, LHP evaporators are fabricated as a stacked structure, consisting from bottom to top of: a substrate – a vapor channel – a capillary wick – a liquid storage chamber, also known as a compensation chamber. This type of LHP evaporator has some limitations, which are determined by its design. For example, the capillary wick must be made of powder with low thermal conductivity, and the overall thickness of the evaporator is relatively high due to the stacked layout of the compensation chamber on the capillary wick body.

[0049] Another type of LHP evaporator has been proposed, in which the liquid storage is configured outside the capillary wick. This type is called an evaporator with longitudinal replenishment. The main advantage here is the opportunity to reduce the overall thickness of the evaporator. However, longitudinal replenishment causes the liquid to have a longer path through the capillary wick with fine pore sizes, thereby increasing the pressure loss of the liquid flow.

[0050] Therefore, according to embodiments of the present invention, a novel evaporator 100 for a loop heat pipe 300 is provided. The evaporator 100 according to the present invention includes two different porous structures and can reduce the thickness of the evaporator 100 and heat leakage from the heat source to the compensation chamber.

[0051] Figures 1a to 1c Different views of an evaporator 100 according to an embodiment of the present invention are shown. The evaporator 100 includes a first porous structure 110 and a second porous structure 112 disposed on a substrate 120. Both the first porous structure 110 and the second porous structure 112 are disposed on a first side 122 of the substrate 120 and extend outward from the first side 122. The outward direction (OD) is... Figure 1aArrows are used to indicate this. The first porous structure 110 and the second porous structure 112 may be disposed adjacent to each other on the substrate 120, and the first porous structure 110 may be disposed at least partially surrounding the second porous structure 112. In the illustrated embodiment, the first porous structure 110 is U-shaped, and the second porous structure 112 is disposed inside the U-shape formed by the first porous structure 110, see particularly [reference needed]. Figure 1c Therefore, in the illustrated embodiment, the first porous structure 110 surrounds three sides of the second porous structure 112.

[0052] refer to Figure 1a and Figure 1b The evaporator 100 also includes an electronic heat source 130 disposed on a second side 124 of the substrate 120. A first side 122 of the substrate 120 may be disposed opposite to the second side 124 of the substrate 120. Therefore, the first and second porous structures 110 and 112 may be disposed on one side of the substrate 120, and the electronic heat source 130 may be disposed on the opposite side of the substrate 120, that is, the substrate 120 may be disposed between the first and second porous structures 110 and 112 and the electronic heat source 130.

[0053] In the illustrated embodiment, the electronic heat source 130 is aligned with the second porous structure 112. For example, one or more edges of the electronic heat source 130 may be aligned with one or more edges of the second porous structure 112 in the outward direction (OD). The electronic heat source 130 and the second porous structure 112 may also have a common center line perpendicular to their extension in the plane of the substrate 120. In an example of the invention, the common center line of the electronic heat source 130 and the second porous structure 112 may be further aligned with the center line of the substrate 120. Furthermore, the electronic heat source 130 and the second porous structure 112 may have similar extensions or dimensions in the plane of the substrate 120 and may be disposed opposite to each other, i.e., located at the same position on the substrate 120 but on either side of the substrate 120.

[0054] refer to Figure 1a and Figure 1b The evaporator 100 also includes a housing 140 surrounding the first porous structure 110 and the second porous structure 112. The housing 140 surrounds the first porous structure 110 and the second porous structure 112 to form a first chamber 150 and a second chamber 152 separated by the first porous structure 110 and the housing 140, as shown below. Figure 1bAs shown. A first chamber 150 may be defined by a first side 122 of a substrate 120, a first porous structure 110, and a housing 140. A second chamber 152 may be defined by the first porous structure 110, a second porous structure 112, and a housing 140. In the illustrated embodiment, the first chamber 150 has a U-shape formed by the first porous structure 110. However, in embodiments, the first chamber 150 may have another shape and / or include two or more separate chambers.

[0055] The first chamber 150 is coupled to the condenser 200 via the input port 160 (as shown in Figure 6). Figure 7 As shown), and is used to receive cooling fluid from condenser 200. Second chamber 152 is coupled to condenser 200 via output port 162 and is used to supply cooling fluid to condenser 200. Input port 160 and output port 162 for coupling evaporator 100 to condenser 200 can be disposed in housing 140, as shown. Figure 1c As shown. In this embodiment, the first chamber 150 is used to receive liquid-phase cooling fluid, and the second chamber 152 is used to supply gas-phase cooling fluid. Referring below to Figure 6 and... Figure 7 Further details are described regarding the coupling between the evaporator 100 and the condenser 200, as well as the flow of the cooling fluid.

[0056] exist Figures 1a to 1c In the illustrated embodiment, one or more microchannels 170 are disposed within the first porous structure 110. The one or more microchannels 170 may be through-holes in the first porous structure 110, having a circular shape, but are not limited thereto. The one or more microchannels 170 can be used to receive cooling fluid from the condenser 200 and supply it to the first chamber 150, see [reference]. Figure 7 Therefore, in an embodiment, the first chamber 150 may be used to receive cooling fluid from the condenser 200 via one or more microchannels 170 disposed within the first porous structure 110. The one or more microchannels 170 may facilitate saturation of the first porous structure 110 by the cooling fluid returning from the condenser 200, thereby facilitating the supply of cooling fluid to the second porous structure 112 through the first porous structure 110, thereby reducing pressure loss as the cooling fluid flows from the first chamber 150 (or from the cooling fluid accumulated in the first chamber 150) through the first porous structure. However, in an embodiment, the first porous structure 110 may not include microchannels 170 or may include one or more microchannels 170 of different shapes or configurations.

[0057] In an embodiment, the first porous structure 110 may include a first pore diameter within a first range, and the second porous structure 112 may include a second pore diameter within a second range, wherein the first pore diameter is smaller than the second pore diameter. Therefore, the first porous structure 110 may have finer pores than the second porous structure 112, i.e., the second porous structure 112 may have coarser pores than the first porous structure 110. In this case, the first porous structure 110 may be referred to as a fine capillary structure, and the second porous structure 112 may be referred to as a coarse capillary structure. For example, the difference in pore size can be achieved by using different metal powders and / or different sintering processes when producing the first porous structure 110 and the second porous structure 112.

[0058] A first porous structure 110 with a smaller first pore size can be disposed in the region surrounding the heat load area, and is continuously filled to saturation by cooling fluid stored in the first chamber 150. It is in contact with the top cover 140 directly or by means of a seal (e.g., a sealing ring) of the evaporator 100, thereby preventing steam leakage into the first chamber 150 through the pores in the first porous structure 110. A second porous structure 112 with a larger second pore size can be disposed in the evaporation region of the evaporator 100 to supply liquid above the heat load area and allow liquid to diffuse from the first chamber 150 along the heat load area through the pores in the second porous structure 112.

[0059] The pore sizes of the first porous structure 110 and the second porous structure 112 can be adjusted based on the usage of the evaporator 100. In a non-limiting embodiment, the first range may include pore sizes less than 10 micrometers, and the second range may include pore sizes greater than 10 micrometers. The difference between the first and second pore sizes can also be greater; for example, the first range may include pore sizes less than 10 micrometers, and the second range may include pore sizes greater than 40 micrometers. Furthermore, the first range may include pore sizes greater than 0.5 micrometers, and the second range may include pore sizes less than 100 micrometers. For example, the first range may be 1 to 5 micrometers, and the second range may be 40 to 60 micrometers.

[0060] In the second porous structure 112, the pore size can also be non-uniform, meaning the second porous structure 112 can include one or more segments having pore sizes different from the rest of the second porous structure 112. Therefore, the second porous structure 112 can include multiple second porous segments with different pore size ranges. In an embodiment, the multiple second porous segments can be arranged with increasing pore sizes toward the centerline of the substrate 120. In this way, pressure loss from the sides of the substrate 120 to the center through the second porous structure 112 can be reduced.

[0061] Figure 2A second porous structure 112 of an evaporator 100 according to one embodiment is shown, wherein the second porous structure 112 includes three second porous segments 112a, 112b, and 112c with different pore size ranges. Reference Figure 2 For example, the central second porous segment 112a may have a larger pore size range than the intermediate second porous segment 112b and the edge second porous segment 112c, while the intermediate second porous segment 112b has a larger pore size range than the edge second porous segment 112c. For example, in a non-limiting example, the central second porous segment 112a may have a pore size range of 40 to 60 micrometers, the intermediate second porous segment 112b may have a pore size range of 20 to 40 micrometers, and the edge second porous segment 112c may have a pore size range of 10 to 20 micrometers. Furthermore, in this case, the first porous structure 110 may have a pore size range of 1 to 5 micrometers.

[0062] Despite Figure 2 While shown as distinct individual segments, in embodiments, multiple second porous segments may alternatively overlap, such that the pore size range gradually varies along the extension direction of the second porous structure 112, for example, gradually increasing towards the center of the second porous structure 112. Therefore, the second porous structure 112 may have a gradient pore size.

[0063] In one embodiment, the height or thickness of the first porous structure 110 is greater than the height or thickness of the second porous structure 112 in the outward direction (OD). Reference Figure 2 The first porous structure 110 can extend in the outward direction (OD) with a first height h1, and the second porous structure 112 can extend in the outward direction (OD) with a second height h2, wherein the second height h2 is less than the first height h1.

[0064] In Figure 1 and Figure 2 In the illustrated embodiment, the first porous structure 110 and the second porous structure 112 extend with a uniform height in the outward direction (OD). In other words, the height of each of the first porous structure 110 and the second porous structure 112 can be uniform in the direction perpendicular to the plane 122 of the substrate 120, i.e., uniform along the extension direction of the substrate 120.

[0065] However, in the embodiments, one or more of the first porous structure 110 and the second porous structure 112 may have a non-uniform height in the outward direction (OD). The non-uniform height may be concave, nearly concave, prismatic, or nearly prismatic in the outward direction (OD). Figure 3a and 3b An embodiment is shown in which a first porous structure 110 extends in the outward direction (OD) with a uniform height, and a second porous structure 112 extends in the outward direction (OD) with a non-uniform height, for example having a central bowl shape.

[0066] exist Figure 3a In the first porous structure 110, the first porous structure 110 extends in the outward direction (OD) with a first height h1, and the second porous structure 112 extends in the outward direction (OD) with a non-uniform height. The second porous structure 112 extends at its ends with a second height h2 equal to the first height h1, but at its central section with a third height h3 less than the second height h2. Starting from each end of the second porous structure 112, the height gradually decreases towards the central section forming the central bowl shape of the second porous structure 112.

[0067] exist Figure 3b In the first porous structure 110, the first porous structure 110 extends in the outward direction (OD) with a first height h1. The second porous structure 112 has a non-uniform height, extending at its ends with a second height h2 less than the first height h1, and at its central section with a third height h3 less than the second height h2. The second porous structure 112 has the following characteristics: Figure 3a Similar shapes as shown.

[0068] In one embodiment, the substrate 120 includes segments with different thermal conductivities. For example, the substrate 120 may be a multi-segment unit with a seam between low-conductivity segments and high-conductivity segments. Figure 4a (Front view of cross section) and Figure 4b (Top cross-sectional view) A substrate 120 according to an embodiment is shown, wherein the substrate 120 has a first substrate segment 126a and a second substrate segment 126b. Reference Figure 4bThe first substrate segment 126a has a first thermal conductivity c1, and the second substrate segment 126b has a second thermal conductivity c2. The second thermal conductivity c2 can be greater than the first thermal conductivity c1. Therefore, the first substrate segment 126a can have a lower thermal conductivity than the second substrate segment 126b. For example, the first substrate segment 126a can be made of stainless steel, nickel, or other metals or metal alloys with lower thermal conductivity. For example, the second substrate segment 126b can be made of copper, copper alloys, aluminum alloys, or other metals or metal alloys with higher thermal conductivity.

[0069] refer to Figure 4a The substrate 120 can be configured such that a first substrate segment 126a supports the first porous structure 110 and the first chamber 150, and a second substrate segment 126b supports the second porous structure 112. Furthermore, the heat source 130 can be aligned with the second substrate segment 126b, for example, disposed on a second side 124 of the second substrate segment 126b opposite to the second porous structure 112. In this way, the first substrate segment 126a, having lower thermal conductivity, can limit the heat flux through the substrate 120 into the first porous structure 110 and the first chamber 150 via thermal conduction, while the second substrate segment 126b, having higher thermal conductivity, can provide lower thermal resistance for the heat flux, which travels from the heat source 130 to the second porous structure 112 via the second substrate segment 126b and effectively evaporates the cooling fluid.

[0070] The evaporator 100 may further include a heat insulation layer 128 disposed between the first porous structure 110 and the substrate 120. The heat insulation layer 128 may have, for example, Figures 5a to 5c The different sizes and shapes shown are illustrated, with the upper figure showing the evaporator 100 in a cross-sectional front view and the lower figure showing the evaporator 100 in a cross-sectional top view.

[0071] exist Figure 5a In the illustrated embodiment, the insulation layer 128 has the same shape as the first porous structure 110 and covers the same area. The insulation layer 128 is also disposed between the first porous structure 110 and the substrate 120, and is aligned with the first porous structure 110. The thickness of the insulation layer can depend on the application and is a target of the thermal design of the evaporator 100. However, in this embodiment, the thickness of the insulation layer can be thinner than the thickness of the metal substrate in its central region, i.e., the region with the thickest metal segment.

[0072] refer to Figure 5b and Figure 5c In other embodiments, the insulation layer 128 may cover an area larger than the first porous structure 110. For example, the insulation layer 128 may extend from the first porous structure 110 to the wall 142 of the housing 140, such as... Figure 5bAs shown. Therefore, the heat insulation layer 128 can be disposed between the first porous structure 110 and the substrate 120, and between the first chamber 150 and the substrate 120. Figure 5c In this case, the heat insulation layer 128 covers an area even larger, extending from the first porous structure 110 and at least partially into the wall 142 of the housing 140. Therefore, the heat insulation layer 128 extends to the exterior of the substrate 120, such as... Figure 5c The top view of the middle substrate 120 is shown.

[0073] Without departing from the scope of the invention, one or more embodiments of the evaporator 100 described herein can be combined into other embodiments. For example, the second porous structure 112 may have a non-uniform height and may include a plurality of second porous segments with different pore size ranges. The substrate 120 may include substrate segments with different thermal conductivity and may be combined with the second porous structure 112, wherein the second porous structure 112 has a uniform or non-uniform height and / or includes a plurality of second porous segments with different pore size ranges. It should also be noted that embodiments with multi-segment substrates can be combined with embodiments with insulating layers.

[0074] According to an embodiment of the present invention, a loop heat pipe 300 is provided comprising an evaporator 100 according to any of the embodiments described herein. Figure 6a and Figure 6b A loop heat pipe 300 with an evaporator 100 is shown according to an embodiment of the present invention. In the illustrated embodiment, the loop heat pipe 300 includes an evaporator 100 and a condenser 200 coupled to the evaporator 100 via an inlet port 160 and an outlet port 162. The loop heat pipe 300 is used to allow a cooling fluid F to circulate between the evaporator 100 and the condenser 200, such as... Figure 6a and Figure 6b As shown by the arrow in the image.

[0075] The input port 160 of the evaporator 100 is coupled to the first chamber 150, that is, the first chamber 150 is coupled to the condenser 200 via the input port 160. The first chamber 150 can be coupled to the condenser 200 directly or via the first porous structure 110.

[0076] The output port 162 of the evaporator 100 is coupled to the second chamber 152, that is, the second chamber 152 is coupled to the condenser 200 through the output port 162. The second chamber 152 is used to supply cooling fluid F to the condenser 200.

[0077] The condenser 200 can supply liquid-phase cooling fluid F to the evaporator 100 via the inlet port 160, and can receive gas-phase cooling fluid F from the evaporator 100 via the outlet port 162. Therefore, the inlet port 160 and the first chamber 150 can be coupled to the condenser 200 via a liquid line 210, such as a liquid pipe, and the outlet port 162 and the second chamber 152 can be coupled to the condenser 200 via a steam line 220, such as a steam pipe. Thus, the first chamber 150 can be used to receive liquid-phase cooling fluid F, and the second chamber 152 can be used to supply gas-phase cooling fluid F.

[0078] In this embodiment, the first chamber 150 is a space for the liquid-phase cooling fluid F, which may correspond to a liquid storage or compensation chamber in a conventional evaporator. The second chamber 152 may be a space for the gaseous-phase cooling fluid. In this embodiment, the second chamber 152 is also used to receive the gaseous-phase cooling fluid F. The gaseous phase of the cooling fluid F is a result of the evaporation process of the cooling fluid F occurring in the second porous structure 112, while the cooling fluid F is continuously supplied from the first chamber 150 to the second porous structure 112 through the first porous structure 110. In other words, the second chamber 152 is used to accumulate the cooling fluid F that evaporates from the second porous structure 112 when a heat load 130 is applied. Therefore, the second chamber 152 is also used to receive the gaseous-phase cooling fluid F from the first chamber 150 through the first porous structure 110.

[0079] Figure 7 A loop heat pipe 300 with an evaporator 100 according to an exemplary embodiment of the present invention is shown, wherein a first porous structure 110 includes one or more microchannels 170. The one or more microchannels 170 may be through-holes in the first porous structure 110 and have a circular shape, but are not limited thereto. Reference Figure 7 The one or more microchannels 170 can form channels extending into the first chamber 150 through a first porous structure 110 having one or more branches. The one or more branches can be located on a face / side of the first porous structure 110 defining the first chamber 150. The one or more microchannels 170 can receive cooling fluid F from the condenser 200 and supply it to the first chamber 150, as... Figure 7As indicated by the arrows in the diagram. Therefore, the first chamber 150 can receive cooling fluid F from the condenser 200 via the one or more microchannels 170 disposed within the first porous structure 110. The one or more microchannels 170 facilitate the supply of cooling fluid F to the first chamber 150 through the first porous structure 110, allowing the cooling fluid F to flow through the first porous structure 110 with lower pressure loss. Furthermore, it helps to saturate the first porous structure 110 with the cooling fluid F, which flows out of the condenser 200 and accumulates in the first chamber 150, and also facilitates the flow of cooling fluid F through the first porous structure 110 to the second porous structure 112, thereby reducing the pressure loss of the cooling fluid flow.

[0080] The loop heat pipe 300 and / or evaporator according to the invention can be oriented in a number of different directions relative to the gravity vector. For example, the principal plane of the loop heat pipe 300 and / or evaporator 100 can be parallel to or perpendicular to the gravity vector or inclined relative to the gravity vector.

[0081] Finally, it should be understood that the present invention is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.

Claims

1. An evaporator (100) for a loop heat pipe (300), characterized in that, The evaporator (100) includes: The first porous structure (110) and the second porous structure (112) are both disposed on the first side (122) of the substrate (120) and extend outward from the first side (122); An electronic heat source (130) is disposed on the second side (124) of the substrate (120); A housing (140) surrounds the first porous structure (110) and the second porous structure (112) to form a first chamber (150) and a second chamber (152) separated by the first porous structure (110) and the housing (140); wherein, The first chamber (150) is coupled to the condenser (200) via an input port (160) and is used to receive cooling fluid (F) from the condenser (200). The second chamber (152) is coupled to the condenser (200) via an output port (162) and is used to supply the cooling fluid (F) to the condenser (200).

2. The evaporator (100) according to claim 1, characterized in that, The first chamber (150) is used to receive the liquid cooling fluid (F). The second chamber (152) is used to supply the gaseous cooling fluid (F).

3. The evaporator (100) according to claim 2, characterized in that, The second chamber (152) is used to receive the gaseous cooling fluid (F) from the first chamber (150) through the first porous structure (110).

4. The evaporator (100) according to any one of the preceding claims, characterized in that, The first chamber (150) is defined by the first side (122) of the substrate (120), the first porous structure (110), and the housing (140). The second chamber (152) is defined by the first porous structure (110), the second porous structure (112) and the shell (140).

5. The evaporator (100) according to any one of the preceding claims, characterized in that, The first side (122) of the substrate (120) is disposed opposite to the second side (124) of the substrate (120).

6. The evaporator (100) according to any one of the preceding claims, characterized in that, The electronic heat source (130) is aligned with the second porous structure (112).

7. The evaporator (100) according to any one of the preceding claims, characterized in that, The first porous structure (110) includes a first pore diameter within a first range, and the second porous structure (112) includes a second pore diameter within a second range, wherein the first pore diameter is smaller than the second pore diameter.

8. The evaporator (100) according to claim 7, characterized in that, The first range includes pore sizes of less than 10 micrometers, and the second range includes pore sizes of more than 10 micrometers.

9. The evaporator (100) according to claim 8, characterized in that, The second range includes pore sizes greater than 40 micrometers.

10. The evaporator (100) according to claim 9, characterized in that, The first range includes pore sizes greater than 0.5 micrometers, and the second range includes pore sizes less than 100 micrometers.

11. The evaporator (100) according to any one of the preceding claims, characterized in that, The second porous structure (112) includes multiple second porous segments with different pore size ranges.

12. The evaporator (100) according to claim 11, characterized in that, The plurality of second porous segments are arranged toward the centerline of the substrate (120) with increasing aperture diameters.

13. The evaporator (100) according to any one of the preceding claims, characterized in that, The first porous structure (110) extends in the outward direction (OD) at a first height (h1). The second porous structure (112) extends in the outward direction (OD) at a second height (h2), which is smaller than the first height (h1).

14. The evaporator (100) according to claim 13, characterized in that, The first porous structure (110) and the second porous structure (112) extend at a uniform height along the outward direction (OD).

15. The evaporator (100) according to claim 14, characterized in that, The first porous structure (110) extends at a uniform height along the outward direction (OD). The second porous structure (112) extends along the outward direction (OD) with an uneven height.

16. The evaporator (100) according to any one of the preceding claims, characterized in that, The substrate (120) includes a first substrate segment (126a) having a first thermal conductivity (c1) and a second substrate segment (126b) having a second thermal conductivity (c2) greater than the first thermal conductivity (c1).

17. The evaporator (100) according to claim 16, characterized in that, The first substrate segment (126a) supports the first porous structure (110) and the first chamber (150), and the second substrate segment (126b) supports the second porous structure (112).

18. The evaporator (100) according to any one of the preceding claims, characterized in that, It also includes a heat insulation layer (128) disposed between the first porous structure (110) and the substrate (120).

19. The evaporator (100) according to claim 18, characterized in that, The insulation layer (128) extends from the first porous structure (110) to the wall (142) of the housing (140) or at least partially into the wall (142).

20. The evaporator (100) according to any one of the preceding claims, characterized in that, The first chamber (150) is used to receive the cooling fluid from the condenser (200) via one or more microchannels (170) disposed inside the first porous structure (110).

21. A loop heat pipe (300), characterized in that, It includes an evaporator (100) according to any one of the preceding claims and a condenser (200) coupled to the evaporator (100) via the input port (160) and the output port (162).

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