Heat dissipation piece air duct optimization method of electronic equipment, heat dissipation piece and electronic equipment

Abstract

The invention provides an air duct optimization method for a heat dissipation part of electronic equipment, the heat dissipation part and the electronic equipment, and the method comprises the steps: building a simulation calculation model of the electronic equipment comprising the heat dissipation part and a fan; the simulation calculation model is imported into simulation software; setting simulation parameters in simulation software and carrying out grid division on the simulation calculation model; heat source parameters are set and solved for the simulation calculation model subjected to grid division, a simulation solving program is rapidly iterated along with time, and a simulation calculation result meeting the convergence condition is obtained; obtaining a working point of the fan from the simulation calculation result; and according to the working point of the fan, the structure of the air duct of the heat dissipation piece is adjusted until the optimal heat dissipation effect is met. The electronic equipment is used for solving the technical problem that the heat dissipation effect of the electronic equipment provided with the heat dissipation piece and the fan is not ideal.

Description

Technical Field

[0001] The present invention relates to the field of heat dissipation design of electronic devices, and particularly to a method for optimizing the air duct of a heat dissipation component of an electronic device, a heat dissipation component and an electronic device. Background Art

[0002] With the rapid development of the electronic industry, more and more electronic components are applied. A large amount of heat is generated when the electronic components operate. If the generated heat cannot be dissipated in time, it will affect the normal operation of the electronic components. Especially in some electronic components equipped with chips, the demand for heat dissipation is higher.

[0003] Currently, a fan and a heat sink are usually installed on the electronic component. The fan is directly fixed on the heat sink. The heat generated by the operation of the electronic component is conducted to the heat sink. The fan blows downward to take away the heat on the heat sink. When a part of the air passes through the heat dissipation fins, it will be blocked due to their shape and bounce back in different directions, causing a part of the air to bounce into the air above the upper cover of the heat sink, resulting in a loss of a part of the air blown by the fan. It does not pass through the middle of the heat sink sufficiently and cannot play the heat dissipation effect well.

[0004] Therefore, it is urgent to improve the heat dissipation effect of an electronic device equipped with a heat dissipation component and a fan. Summary of the Invention

[0005] The present invention provides a method for optimizing the air duct of a heat dissipation component of an electronic device, a heat dissipation component and an electronic device, so as to solve the technical problem that the heat dissipation effect of an electronic device equipped with a heat dissipation component and a fan is not ideal.

[0006] In order to achieve the above object, the present invention provides a method for optimizing the air duct of a heat dissipation component of an electronic device. The electronic device includes a circuit board assembly, a heat dissipation component and a fan. The first surface of the heat dissipation component abuts against the circuit board assembly. The circuit board assembly includes a chip. The second surface of the heat dissipation component has a plurality of heat dissipation fins. An air duct is formed between two adjacent heat dissipation fins. The fan is disposed on the second surface of the heat dissipation component. The method includes:

[0007] Establishing a simulation calculation model of an electronic device including the heat dissipation component and the fan;

[0008] Importing the simulation calculation model into simulation software;

[0009] Setting simulation parameters in the simulation software and performing mesh division on the simulation calculation model;

[0010] Setting heat source parameters for the simulation calculation model after mesh division and solving, wherein the simulation solving program rapidly iterates over time to obtain a simulation calculation result that meets the convergence condition;

[0011] Obtain the operating point of the fan from the simulation calculation results;

[0012] According to the operating point of the fan, adjust the structure of the air duct of the heat dissipation component until the optimal heat dissipation effect is achieved.

[0013] A method for optimizing the air duct of a heat dissipation component of an electronic device provided by the present invention optimizes the air duct design through simulation calculation results, balances the resistance of the fan, so that when the fan operates, the air pressure generated can overcome the system resistance, obtains the optimal operating point of the fan according to the thermal simulation software, removes the heat generated by the circuit board component to the greatest extent, improves the heat dissipation effect, and improves the utilization rate and service life of the fan.

[0014] In a possible implementation manner, the obtaining the operating point of the fan from the simulation calculation results specifically includes:

[0015] Obtain the differential pressure curve of the fan and the system resistance curve formed when the fluid passes through the air duct, wherein the differential pressure curve of the fan is the characteristic curve of the fan, and the system resistance curve formed when the fluid passes through the air duct is the sum of the system resistances suffered by the fluid passing through the air duct;

[0016] Take the intersection point of the differential pressure curve of the fan and the system resistance curve of the fluid passing through the air duct as the operating point of the fan.

[0017] In a possible implementation manner, in the establishing of the simulation calculation model of the electronic device including the heat dissipation component and the fan, the fan is selected according to the required air volume value;

[0018] The air volume of the selected fan is 1.2 to 1.5 times the actually required air volume value;

[0019] The actually required air volume value: q = 3600Q / (ρCpΔt),

[0020] where, q is the actually required air volume, with the unit of m3 / h;

[0021] Q is the total heat dissipation of the system, with the unit of W;

[0022] ρ is the air density, with the unit of kg / m3;

[0023] Cp is the specific heat capacity of air, with the unit of J / kg·°C;

[0024] Δt is the temperature rise of air, with the unit of °C.

[0025] In a possible implementation manner, the mesh generation for the simulation calculation model includes:

[0026] Automatically divide the mesh of the simulation calculation model;

[0027] Manually perform local mesh refinement on the chip and the heat dissipation fins of the simulation calculation model with automatically segmented meshes.

[0028] In a possible implementation manner, after obtaining the simulation calculation result that meets the convergence condition, it further includes comparing the heat source temperature according to the simulation calculation result to determine whether the electronic device meets the heat dissipation requirement, specifically including:

[0029] Compare the temperature value of the chip of the circuit board assembly with the preset specification value;

[0030] If the temperature value of the chip is greater than the preset specification value, it is determined that the heat dissipation requirement is not met;

[0031] If the temperature value of the chip is less than or equal to the preset specification value, it is determined that the heat dissipation requirement is met.

[0032] In a possible implementation manner, adjusting the structure of the air duct of the heat dissipation component according to the operating point of the fan includes:

[0033] When the operating point of the fan is located in the latter 1 / 3 section of the pressure difference curve of the fan, extend the length of the heat dissipation fins;

[0034] When the operating point of the fan is located in the former 1 / 2 section of the pressure difference curve of the fan, add rounded corners to one end of some of the heat dissipation fins close to the fan, so that some of the air ducts on both sides of the fan present a corner shape.

[0035] In a possible implementation manner, meeting the optimal heat dissipation effect specifically includes:

[0036] The electronic device meets the heat dissipation requirement, and the operating point of the fan is located in the latter 1 / 3 section of the pressure difference curve of the fan. The air pressure of the fan is in the range of 1 / 5 times to 1 / 2 times of the maximum static pressure of the fan, and the slope of the pressure difference curve of the fan near the operating point of the fan is gentle.

[0037] This application also provides a heat dissipation component, which is a heat dissipation component formed by using the heat dissipation component air duct optimization method of the above-mentioned electronic device;

[0038] One side of the heat dissipation component has a first heat dissipation area, a second heat dissipation area and an installation position for accommodating a fan. A plurality of heat dissipation fins are arranged in both the first heat dissipation area and the second heat dissipation area. An air duct is formed between two adjacent heat dissipation fins. One end of each heat dissipation fin faces the installation position, and the other end of each heat dissipation fin extends to the side edge of the heat dissipation component.

[0039] In a possible implementation manner, the first heat dissipation area and the installation position are located between the two second heat dissipation areas;

[0040] The heat dissipation fins located in the first heat dissipation area include a first extension portion;

[0041] The heat dissipation fins located in the second heat dissipation area include a second extension portion, a third extension portion, and a rounded corner portion. The rounded corner portion is connected between the second extension portion and the third extension portion. The extension direction of the second extension portion is the same as the extension direction of the first extension portion, and there is an included angle between the extension direction of the third extension portion and the extension direction of the second extension portion.

[0042] The present application further provides an electronic device, including a circuit board assembly, a fan, and the above heat dissipation component. The heat dissipation component abuts against the circuit board assembly. The circuit board assembly includes a plurality of chips, and the positions of the plurality of chips correspond to the positions of the first heat dissipation area and the second heat dissipation area of the heat dissipation component.

[0043] The heat dissipation component air duct optimization method, heat dissipation component, and electronic device provided by the present invention determine whether the design of the air duct is effective according to the operating point of the fan, and optimize the air flow path by adjusting the structure of the air duct to improve the heat dissipation efficiency. Among them, adjusting the structure of the air duct includes adjusting parameters such as the shape, position, and size of the air duct, so that the structure of the air duct is optimized to improve the heat dissipation efficiency of the electronic device.

[0044] The heat dissipation component air duct optimization method, heat dissipation component, and electronic device provided by the present invention combine the characteristics of the heat dissipation component and the fan, so that the fan is well utilized, and the structure of the heat dissipation component is optimized, reducing the vortex phenomenon generated around the fan by the air blown by the fan to the heat dissipation component, so that more air can be introduced into the air duct, thereby taking away the heat on the surface of the heat dissipation fins and improving the heat dissipation effect.

[0045] In addition to the technical problems solved by the embodiments of the present invention described above, the technical features constituting the technical solutions, and the beneficial effects brought by these technical features of the technical solutions, other technical problems that can be solved by the heat dissipation component air duct optimization method, heat dissipation component, and electronic device provided by the embodiments of the present invention, other technical features included in the technical solutions, and the beneficial effects brought by these technical features will be further described in detail in the specific implementation manner. Description of the Drawings

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0047] Figure 1 It is an exploded view of a partial structure of the electronic device provided by an embodiment of the present invention;

[0048] Figure 2 It is a top view of a partial structure of the electronic device provided by an embodiment of the present invention;

[0049] Figure 3 It is a differential pressure curve graph of the fan of the electronic device provided by an embodiment of the present invention;

[0050] Figure 4 It is a flowchart of the heat dissipation component air duct optimization method of the electronic device provided by an embodiment of the present invention;

[0051] Figure 5 It is a top view of the heat dissipation component of the electronic device provided by Embodiment 1 of the present invention;

[0052] Figure 6 It is a graph of the differential pressure curve of the fan of the electronic device and the system resistance curve through which the fluid passes provided by Embodiment 1 of the present invention;

[0053] Figure 7 It is a top view of the heat dissipation component of the electronic device provided by Embodiment 2 of the present invention;

[0054] Figure 8 It is a graph of the differential pressure curve of the fan of the electronic device and the system resistance curve through which the fluid passes provided by Embodiment 2 of the present invention;

[0055] Figure 9 It is a top view of the heat dissipation component of the electronic device provided by Embodiment 3 of the present invention;

[0056] Figure 10 It is a graph of the differential pressure curve of the fan of the electronic device and the system resistance curve through which the fluid passes provided by Embodiment 3 of the present invention;

[0057] Figure 11 It is a schematic structural diagram of the circuit board assembly of the electronic device provided by an embodiment of the present invention;

[0058] Figure 12 It is a schematic structural diagram of the circuit board assembly and the heat dissipation component of the electronic device provided by Embodiment 3 of the present invention;

[0059] Figure 13Partial flowchart of the heat dissipation component air duct optimization method for the electronic device provided by the embodiment of the present invention;

[0060] Figure 14 Another partial flowchart of the heat dissipation component air duct optimization method for the electronic device provided by the embodiment of the present invention;

[0061] Figure 15 Another partial flowchart of the heat dissipation component air duct optimization method for the electronic device provided by the embodiment of the present invention.

[0062] Explanation of reference numerals:

[0063] 10 - Circuit board assembly;

[0064] 11 - First chip;

[0065] 12 - Second chip;

[0066] 13 - Third chip;

[0067] 14 - Fourth chip;

[0068] 20 - Heat dissipation component;

[0069] 21 - Heat dissipation fins;

[0070] 211 - First extension;

[0071] 212 - Second extension;

[0072] 213 - Third extension;

[0073] 22 - Air duct;

[0074] 23 - Installation position;

[0075] 24 - Rounded corner part;

[0076] 25 - First heat dissipation area;

[0077] 26 - Second heat dissipation area;

[0078] 30 - Fan;

[0079] 40 - Upper cover plate;

[0080] 50 - Housing. Detailed implementation manners

[0081] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0082] Currently, in some electronic devices, a fan is combined with a heat sink for heat dissipation. The wind blown by the fan cannot be effectively utilized, and a part of it will be lost, so that the heat dissipation effect cannot be well exerted. Moreover, when the wind blown by the fan flows through the heat sink, the pressure loss is too large, affecting the heat dissipation effect.

[0083] In view of this, the present invention provides a method for optimizing the air duct of a heat sink of an electronic device, a heat sink and an electronic device. By analyzing the results, the air duct is optimized and designed to balance the resistance of the fan, split the wind blown by the fan, and reduce the energy loss caused by eddy currents and the like. According to the thermal simulation software, the optimal operating point of the fan is obtained, and the heat generated by the circuit board assembly is taken away to the greatest extent, improving the heat dissipation effect, enabling the fan to work in a stable and efficient state, and improving the utilization rate and service life of the fan.

[0084] The following describes a method for optimizing the air duct of a heat sink of an electronic device, a heat sink and an electronic device provided by an embodiment of the present invention with reference to the accompanying drawings.

[0085] Refer to Figure 1 and Figure 2 As shown, the present invention provides a method for optimizing the air duct of a heat sink of an electronic device. The electronic device includes a circuit board assembly 10, a heat sink 20 and a fan 30. The first surface of the heat sink 20 abuts against the circuit board assembly 10. The circuit board assembly 10 includes a chip. The second surface of the heat sink 20 has a plurality of heat dissipation fins 21. An air duct 22 is formed between two adjacent heat dissipation fins 21. The fan 30 is disposed on the second surface of the heat sink 20. Refer to Figure 4 As shown, the method for optimizing the air duct of a heat sink of an electronic device includes:

[0086] S10. Establish a simulation calculation model of an electronic device including a heat sink and a fan;

[0087] S20. Import the simulation calculation model into a simulation software;

[0088] S30. Set simulation parameters in the simulation software and perform mesh division on the simulation calculation model;

[0089] S40. Set heat source parameters for the simulation calculation model after mesh division and solve it. Among them, the simulation solving program iterates quickly over time to obtain a simulation calculation result that meets the convergence condition;

[0090] S50. Obtain the operating point of the fan from the simulation calculation results;

[0091] S60. According to the operating point of the fan, adjust the structure of the air duct of the heat dissipation component until the optimal heat dissipation effect is achieved.

[0092] A method for optimizing the air duct of a heat dissipation component of an electronic device provided by the present invention calculates simulation calculation results through simulation software, optimizes the design of the air duct 22, balances the resistance of the fan 30, diverts the air blown out by the fan 30, and reduces energy loss caused by eddy currents, etc. According to the thermal simulation software, the optimal operating point of the fan is obtained, and the heat generated by the circuit board assembly 10 is taken away to the greatest extent, improving the heat dissipation effect and the utilization rate and service life of the fan 30.

[0093] In this application, according to the operating point of the fan 30, it is judged whether the design of the air duct 22 is effective, and the air flow path is optimized by adjusting the structure of the air duct 22 to improve the heat dissipation efficiency. Among them, adjusting the structure of the air duct 22 includes adjusting parameters such as the shape, position, and size of the air duct 22, so that the structure of the air duct 22 is optimized to improve the heat dissipation efficiency of the electronic device.

[0094] A method for optimizing the air duct of a heat dissipation component of an electronic device provided by the present invention combines the characteristics of the heat dissipation component 20 and the fan 30, so that the fan 30 is well utilized, and the structure of the heat dissipation component 20 is optimized, reducing the eddy current phenomenon generated around the fan 30 by the air blown by the fan 30 to the heat dissipation component 20, so that more air can be introduced into the air duct 22, thereby taking away the heat conducted from the circuit board assembly 10 to the heat dissipation fins 21 and improving the heat dissipation effect.

[0095] Step S10. Establish a simulation calculation model of an electronic device including a heat dissipation component and a fan, aiming to create a complete electronic device model including the heat dissipation component 20 and the fan 30, and ensure that the dimensions and material properties in the simulation calculation model accurately reflect the actual electronic device.

[0096] Step S20. Import the simulation calculation model into the simulation software, and it is necessary to ensure that the dimensions and material information of the simulation calculation model are kept complete during the import process.

[0097] The simulation software uses numerical methods and gradually approaches the solution of the problem through rapid iteration. Each iteration updates the physical parameters in the model to gradually approach the real physical behavior. During the iteration process, the software checks the convergence of the calculation results, that is, whether the results are stable and reach the expected accuracy. When the results converge, the simulation calculation can stop and the final simulation results can be obtained. Through this rapid iteration method, the simulation software can effectively simulate complex thermal fluid problems.

[0098] In a possible implementation manner, refer toFigure 13 As shown in , step S50: Obtain the operating point of the fan from the simulation calculation results, specifically including:

[0099] S51: Obtain the pressure difference curve of the fan and the system resistance curve formed when the fluid passes through the air duct. Among them, the pressure difference curve of the fan is the characteristic curve of the fan, and the system resistance curve formed when the fluid passes through the air duct is the sum of the system resistances suffered by the fluid passing through the air duct;

[0100] S52: Take the intersection point of the pressure difference curve of the fan and the system resistance curve of the fluid passing through the air duct as the operating point of the fan.

[0101] The system resistance curve formed when the fluid passes through the air duct 22 is the sum of the system resistances suffered by the fluid passing through the air duct 22, including the frictional resistance and the local resistance, and usually manifests as the pressure difference between the inlet and the outlet of the air duct 22. This curve is the connection line of different resistance values corresponding to different wind speeds and is affected by various factors such as each device, structure, layout, shape, area, etc. inside the electronic device system. The system resistance curve is generally obtained through wind tunnel testing.

[0102] It should be noted that try to make the air volume at the operating point of the fan 30 be within the latter 1 / 3 range of the pressure difference curve of the fan 30, and the wind pressure be within the range of 1 / 5 times to 1 / 2 times of the maximum static pressure of the fan, that is, Figure 3 the position shown by the dotted circle in Figure 3 , refer to Figure 3 As shown in , the operating point of the fan 30 at the position shown by the dotted circle indicates a better heat dissipation effect.

[0103] Refer to Figure 3 As shown in , the pressure difference curve (or performance curve) of the fan 30 is a relationship diagram of the pressure difference generated by the fan 30 at different flow rates. The pressure difference curve of the fan 30 reflects the inherent characteristics of the fan.

[0104] The operating point of the fan 30 is jointly determined by the pressure difference curve of the fan 30 and the system resistance curve of the fluid passing through the air duct 22. The pressure difference curve of the fan 30 is the characteristic curve of the fan 30 itself, which reflects the relationship between the air volume and the wind pressure that the fan 30 can provide at different rotational speeds. Generally, as the air volume increases, the wind pressure will gradually decrease. This is because when the fan 30 pushes the air, the greater the air volume, the greater the speed and flow rate of the air flow, and the relatively smaller the pressure that the fan 30 can exert on the air.

[0105] The system resistance curve of the fluid passing through the air duct 22 reflects the relationship between the resistance encountered by the air when flowing in the entire ventilation system (including components such as air ducts, filters, radiators, etc.) and the air volume. The resistance increases as the air volume increases because when the air volume increases, the friction, collision, etc. between the air and each component in the system intensify, resulting in an increase in the resistance.

[0106] In this application, when the simulation software performs parsing, the simulation software will generate the operating point of the fan.

[0107] Set the materials of all parts in the parsing, such as the materials of the chips, printed circuit boards (PCBs), metal casings of electronic devices, thermal conductive adhesives, etc. in the circuit board assembly 10. According to the model of the selected fan 30, set the pressure difference curve of the fan 30, also known as the fan performance curve. Usually, the abscissa represents the volume flow rate in m3 / s, and the ordinate represents the pressure difference in Pa. The pressure difference curve of the fan 30 intuitively shows the pressure difference that the fan 30 can generate at different flow rates.

[0108] In the same coordinate system, plot the pressure difference curve of the fan 30 and the system resistance curve of the fluid passing through the air duct 22. The horizontal axis usually represents the flow rate, and the vertical axis represents the pressure difference. The intersection point of the two curves is the operating point of the fan 30. At this operating point of the fan 30, the pressure difference provided by the fan 30 exactly overcomes the total resistance of the fluid passing through.

[0109] As the flow rate increases, the pressure difference generated by the fan 30 usually decreases because at high flow rates, the fan 30 needs to overcome greater kinetic energy losses. The resistance of the fluid passing through the air duct 22 usually increases with the increase in the flow rate because higher flow velocities result in greater frictional losses and turbulent effects.

[0110] In a possible implementation manner, in the simulation calculation model of the electronic device including the heat dissipation component 20 and the fan 30, the fan 30 is selected according to the required air volume value;

[0111] The air volume of the selected fan 30 is 1.2 - 1.5 times the actually required air volume value;

[0112] Actually required air volume value: q = 3600Q / (ρCpΔt),

[0113] where q is the actually required air volume, in m3 / h;

[0114] Q is the total heat dissipation of the system, in W;

[0115] ρ is the air density, in kg / m3;

[0116] Cp is the specific heat capacity of air, in J / kg·℃;

[0117] Δt is the air temperature rise, in ℃.

[0118] Calculate the actual required air volume of the device using the above formula. To ensure effective heat dissipation of the system under various conditions, the air volume of the selected fan 30 should be 1.2 to 1.5 times the actual required air volume, taking into account factors such as potential increased resistance and decreased fan performance.

[0119] In a possible implementation, set the simulation parameters in the simulation software. The simulation parameters include: analysis type, gravity condition, fluid material type, solid material type, wall roughness, initial fluid temperature, initial solid temperature, local solid material properties, heat conduction, heat radiation properties, and the size of the computational domain.

[0120] Among them, determine the basic type of the simulation, such as steady-state analysis or transient analysis. Steady-state analysis is used to study the behavior of the system in a stable state, while transient analysis is used to study the dynamic behavior that changes over time.

[0121] The gravity condition includes the direction and magnitude of gravity, usually the standard gravity of the earth 9.81 m / s2, and gravity affects the direction of natural convection and fluid flow.

[0122] The fluid material type, such as air, water, or other specific fluids. In this example, the selected fluid material is air to ensure that the physical properties of the fluid, such as density and viscosity, are accurately reflected in the simulation.

[0123] The solid material type specifies the material type for each solid part in the model, such as aluminum, copper, or plastic. Since material properties such as thermal conductivity and density affect heat conduction and structural response, they need to be selected according to the actual materials used.

[0124] Set the wall roughness in the model, which affects the boundary layer characteristics and frictional losses of fluid flow, usually in meters or millimeters.

[0125] Specify the initial temperature of the solid part to ensure it is consistent with the initial fluid temperature or set according to the actual situation. Local solid material properties, which are considered because some solid regions have different material properties such as composite materials or locally strengthened regions, and the material properties of these regions need to be set separately to effectively simulate the actual situation of the electronic device.

[0126] Set the heat conduction properties, including thermal conductivity and contact thermal resistance, to ensure that these parameters accurately reflect the thermal performance of the material.

[0127] Define the size of the computational domain to ensure that the simulation area is large enough to capture all relevant physical phenomena, but not too large to increase the computational cost. The computational domain should include all important fluid and heat conduction paths.

[0128] By carefully setting these simulation parameters, the simulation software can accurately simulate complex thermo-fluid phenomena and perform simulation analysis on the heat dissipation of the electronic device provided in this application.

[0129] In a possible implementation manner, referring to Figure 14 as shown, mesh generation is performed on the simulation calculation model, including:

[0130] S31. Automatically divide the mesh of the simulation calculation model;

[0131] S32. Manually perform local mesh refinement on the chip and heat dissipation fins of the simulation calculation model with automatically divided mesh.

[0132] For mesh generation of the simulation calculation model, use the automatic mesh generation tool in the simulation software, but the user can manually adjust as needed. Coarser meshes are used in less important areas, which can reduce the computational amount. The mesh density is increased in some important areas such as near the heat source. Specifically, manual local mesh refinement is performed at the positions of the chips and heat dissipation fins 21 of the circuit board assembly 10, and the mesh density of the air duct 22 area is increased, which can improve the computational accuracy.

[0133] In a possible implementation manner, heat source parameters are set for the simulation calculation model after mesh generation, including: setting corresponding heat source parameters according to the heat generation power of each chip on the circuit board assembly 10.

[0134] In the simulation software, a heat source is specified for each chip, and the heat generation power of the chip is input as the heat source parameter to ensure that the geometric position and size of the heat source match the actual chip, so as to accurately simulate the heat distribution. According to the working characteristics of the chip, a suitable heat source type is selected.

[0135] In this embodiment, referring to Figure 11 and Figure 12 as shown, the circuit board assembly 10 includes a circuit board and 4 chips arranged on the circuit board. The 4 chips are the first chip 11, the second chip 12, the third chip 13, and the fourth chip 14 respectively. The corresponding heat source parameters of the first chip 11, the second chip 12, the third chip 13, and the fourth chip 14 are set respectively, and the heat source type is selected to facilitate comparison with the corresponding heat dissipation preset specification values after simulation analysis.

[0136] In a possible implementation manner, the above-mentioned simulation software includes but is not limited to Floefd simulation software, and can also be Ansys Fluent simulation software, Simcenter Flotherm simulation software, etc.

[0137] Among them, (Simcenter FLOEFD, hereinafter referred to as Floefd) is an embedded general computational fluid dynamics (CFD) simulation software. The main features of the Floefd simulation software are its ease of use and seamless integration with CAD, which facilitates fluid and thermal analysis.

[0138] In a possible implementation, referring to Figure 15 as shown, after obtaining the simulation calculation results that meet the convergence conditions, it further includes comparing the heat source temperature according to the simulation calculation results to determine whether the electronic device meets the heat dissipation requirements, specifically including:

[0139] S70. Compare the temperature value of the chip of the circuit board assembly with the preset specification value;

[0140] S80. If the temperature value of the chip is greater than the preset specification value, it is determined that the heat dissipation requirement is not met;

[0141] S90. If the temperature value of the chip is less than or equal to the preset specification value, it is determined that the heat dissipation requirement is met.

[0142] It is easy to understand that if the temperature value of the chip is greater than the preset specification value, this may lead to a decrease or damage in the chip performance. If the heat generated by the chip cannot be dissipated in a timely and effective manner, it will affect the service life of the chip and cause problems such as malfunctions of the electronic device.

[0143] In a possible implementation, in step S60, according to the operating point of the fan 30, adjusting the structure of the air duct 22 of the heat dissipation member 20 includes:

[0144] When the operating point of the fan is in the latter 1 / 3 section of the pressure difference curve of the fan, extend the length of the heat dissipation fins;

[0145] When the operating point of the fan is in the former 1 / 2 section of the pressure difference curve of the fan, add rounded corners at one end of some heat dissipation fins close to the fan, so that part of the air ducts on both sides of the fan show a corner shape.

[0146] The pressure difference curve of the fan 30 is from left to right, with the left side being the front end and the right side being the rear end. When the operating point of the fan 30 is in the latter 1 / 3 section of the pressure difference curve of the fan 30, it usually means that the fan 30 is operating at a higher flow rate and the wind resistance of the system is lower, and it is necessary to increase the heat exchange area. By extending the length of the side of the heat dissipation member 20 close to the fan 30, the length of the air duct 22 can be extended. In this example, by extending the length of the heat dissipation fins, the length of the air duct 22 is extended to help the air flow smoothly, spread the passing air, and thus improve the heat dissipation efficiency.

[0147] When the operating point of the fan 30 is located in the first half of the differential pressure curve of the fan 30, the fan may operate at a relatively low flow rate, with a large system resistance, unable to provide a high air volume, and consuming a large amount of power itself. By adding a rounded corner portion 24 to one end of the heat dissipation fins 21 close to the fan and making the partial air ducts 22 on both sides of the fan present a corner shape, adding the rounded corner portion 24 can reduce the flow resistance and the formation of eddy currents, improve the air flow path, adjust the structure of the air duct 22, reduce energy losses, and guide the air flow to pass through the heat dissipation area more effectively.

[0148] In a possible implementation, when the operating point of the fan is located between the first half and the last third of the differential pressure curve of the fan, a rounded corner portion is added to one end of some of the heat dissipation fins close to the fan, such that the partial air ducts on both sides of the fan present a corner shape.

[0149] In a possible implementation, to achieve the optimal heat dissipation effect, specifically including: the electronic device meets the heat dissipation requirements, and the operating point of the fan 30 is located in the last third of the differential pressure curve of the fan 30, the air pressure of the fan 30 is within the range of 1 / 5 times to 1 / 2 times of the maximum static pressure of the fan, and the slope of the differential pressure curve of the fan 30 near the operating point of the fan 30 is gentle.

[0150] Among them, the operating point of the fan 30 being located in the last third of the differential pressure curve of the fan 30 means that the fan 30 operates at a relatively high flow rate, the air resistance of the system is low, and the air pressure of the fan 30 is within the range of 1 / 5 times to 1 / 2 times of the maximum static pressure of the fan, to ensure that the fan 30 operates within an effective operating range, thereby optimizing the heat dissipation effect. The gentle slope of the differential pressure curve of the fan 30 near the operating point of the fan 30 means that a stable air flow and pressure change can be provided near this operating point, without a sharp increase or decrease in the air volume, enabling the fan 30 to operate stably and efficiently, improving the heat dissipation effect.

[0151] The present application also provides a heat dissipation component, and the heat dissipation component 20 is a heat dissipation component 20 formed by using the above-mentioned method for optimizing the air duct of the heat dissipation component of the electronic device.

[0152] One side of the heat dissipation component 20 has a first heat dissipation area 25, a second heat dissipation area 26, and an installation position 23 for accommodating the fan 30. A plurality of heat dissipation fins 21 are provided in both the first heat dissipation area 25 and the second heat dissipation area 26. An air duct 22 is formed between two adjacent heat dissipation fins 21. One end of each heat dissipation fin 21 faces the installation position 23, and the other end of each heat dissipation fin 21 extends to the side edge of the heat dissipation component 20. This design is used in an electronic device to help manage and dissipate the heat generated during the operation of the device, thereby ensuring the stable operation of the device and extending its service life.

[0153] A plurality of heat dissipation fins 21 are provided in both the first heat dissipation area 25 and the second heat dissipation area 26, which are used to increase the heat dissipation surface area of the heat dissipation member 20, thereby improving the heat dissipation efficiency. An air duct 22 is formed between two adjacent heat dissipation fins 21, which helps to guide the air to flow along the air duct 22, taking away the heat on the surface of the heat dissipation fins 21, thereby improving the heat dissipation efficiency.

[0154] The installation position 23 is used to accommodate the fan 30, and the function of the fan 30 is to enhance the heat dissipation effect through air flow. One end of each heat dissipation fin 21 faces the installation position 23, so as to better utilize the air flow generated by the fan 30 and guide the air flow generated by the fan 30 into the air duct 22. The other end of each heat dissipation fin 21 extends to the same side edge of the heat dissipation member 20, which can maximize the heat dissipation area.

[0155] The thickness of each heat dissipation fin 21 and the distance between two adjacent heat dissipation fins 21 can be flexibly selected according to the use requirements, and no specific limitation is made here.

[0156] In a possible implementation manner, the heat dissipation member 20 can be made of aluminum, copper, an alloy containing aluminum, or an alloy containing copper, so that it has good thermal conductivity and can conduct the heat generated by the operation of the circuit board assembly 10 to the heat dissipation member 20 itself in a timely and efficient manner.

[0157] In a possible implementation manner, refer to Figure 9 As shown, the number of the second heat dissipation areas 26 can be two, and the number of the first heat dissipation areas 25 can be one.

[0158] In a possible implementation manner, refer to Figure 9 As shown, both the first heat dissipation area 25 and the installation position 23 are located between the two second heat dissipation areas 26;

[0159] The heat dissipation fins 21 located in the first heat dissipation area 25 include a first extension portion 211;

[0160] The heat dissipation fins 21 located in the second heat dissipation area 26 include a second extension portion 212, a third extension portion 213, and a rounded corner portion 24. The rounded corner portion 24 is connected between the second extension portion 212 and the third extension portion 213. The extension direction of the second extension portion 212 is the same as that of the first extension portion 211, and there is an included angle between the extension direction of the third extension portion 213 and the extension direction of the second extension portion 212.

[0161] In a possible implementation manner, the first extension portion 211 extends linearly, both the second extension portion 212 and the third extension portion 213 extend linearly, and the included angle between the extension direction of the third extension portion 213 and the extension direction of the second extension portion 212 can be, for example, 80°, 90°, 100°, or 120°, etc.

[0162] The rounded corner portion 24 avoids the existence of a right angle between the second extension portion 212 and the third extension portion 213, which helps to achieve better air guiding and heat dissipation effects.

[0163] Reference Figure 1 and Figure 12 As shown, the present application also provides an electronic device, including a circuit board assembly 10, a fan 30, and the above heat dissipation member. The heat dissipation member 20 abuts against the circuit board assembly 10. The circuit board assembly 10 has a plurality of chips, and the positions of the plurality of chips correspond to the positions of the first heat dissipation area 25 and the second heat dissipation area 26.

[0164] In a possible implementation manner, the first surface of the heat dissipation member 20 abuts against the heat generating surface of the circuit board assembly 10, the fan 30 is disposed on the second surface of the heat dissipation member 20, and an electronic device provided by the present application further includes a housing 50, and the circuit board assembly 10 can be fixed to the housing 50.

[0165] In a possible implementation manner, reference Figure 1 As shown, an electronic device provided by the present application further includes an upper cover plate 40. The upper cover plate 40 covers the surface of the heat dissipation member 20 facing away from the circuit board assembly 10. The upper cover plate 40 blocks all the airflows blown by the fan 30, so that the air provided by the fan 30 flows in the air duct 22, and the air volume loss is small.

[0166] In a possible implementation manner, an electronic device provided by the present application includes, but is not limited to, a controller for a vehicle.

[0167] Next, the simulation result analysis is carried out for 3 different structures of the heat dissipation member 20:

[0168] Example 1

[0169] Reference Figure 1 , Figure 5 and Figure 12 As shown, the circuit board assembly 10 includes a circuit board and 4 chips disposed on the circuit board, namely a first chip 11, a second chip 12, a third chip 13, and a fourth chip 14. The temperatures of the first chip 11, the second chip 12, the third chip 13, and the fourth chip 14 in the simulation calculation results are used as the key heat source temperatures and compared with the corresponding heat dissipation preset specification values respectively.

[0170] In this Example 1, the surface of the heat dissipation member 20 facing away from the circuit board assembly 10 has a plurality of heat dissipation fins 21. The length of each heat dissipation fin 21 is the same, and the extending directions are all the same. An air duct 22 is formed between every two adjacent heat dissipation fins 21.

[0171] As shown in Table 1, the first chip 11, the second chip 12, and the fourth chip 14 have good heat dissipation effects. From the perspective of the temperature of the heating chips, the first chip 11, the second chip 12, and the fourth chip 14 respectively meet the corresponding preset specification values for chip heat dissipation. The temperature of the third chip 13 does not meet the preset specification value for chip heat dissipation and does not achieve a good heat dissipation effect. Combining Figure 6 with the operating points of the fan curve shown, the structure of the heat dissipation component 20 in the first embodiment is not optimal.

[0172] Table 1

[0173]

[0174]

[0175] The heat dissipation specification value of the chip, that is, the preset specification value, is the highest temperature allowed for the chip. The first chip 11, the second chip 12, the third chip 13, and the fourth chip 14 each have corresponding heat dissipation specification values, and the heat dissipation specification values can be set according to the heat dissipation requirements of the chip.

[0176] Refer to Figure 6 shown. The curve drawn with a solid line is the pressure difference curve of the fan 30, and the curve drawn with a double-dot dash line is the operating curve of the fan 30, which is also the actual application curve of the fan 30. The operating point is the operating point of the fan in the analysis result.

[0177] Analysis of the operating point of the fan: The operating point of the fan 30 is jointly determined by the pressure difference curve of the fan 30 and the system resistance curve of the fluid passing through the air duct 22. The operating point of the fan 30 falls on the latter 1 / 3 section of the pressure difference curve of the fan 30, indicating that the system air resistance is low. It is necessary to increase the heat exchange area and lengthen the shape of the existing heat dissipation fins 21 to allow the passing air to spread out.

[0178] Embodiment 2

[0179] In the second embodiment, referring to Figure 1 and Figure 7 shown, the side of the heat dissipation component 20 facing away from the circuit board assembly 10 has a plurality of heat dissipation fins 21. The extending directions of the respective heat dissipation fins 21 are all the same. Some of the heat dissipation fins 21 located at the middle position among the plurality of heat dissipation fins 21 have shorter lengths. From the middle position of the heat dissipation fins 21 to the two side positions, the lengths of some of the heat dissipation fins 21 increase in sequence. An air duct 22 is formed between every two adjacent heat dissipation fins 21.

[0180] Refer to Figure 11As shown, the temperatures of the first chip 11, the second chip 12, the third chip 13, and the fourth chip 14 in the simulation calculation results are used as the key heat source temperatures and compared with the corresponding heat dissipation preset specification values respectively. And the results are shown in Table 2. Among them, the first chip 11, the second chip 12, the third chip 13, and the fourth chip 14 all have good heat dissipation effects.

[0181] Table 2

[0182] Item Heat dissipation specification value of the chip Simulation result Temperature judgment First chip 125℃ 113.73℃ Meet Second chip 125℃ 106.9℃ Meet Third chip 110℃ 108.51℃ Meet Fourth chip 125℃ 121.66℃ Meet

[0183] Judging from the comparison results of the temperatures of the first chip 11, the second chip 12, the third chip 13, and the fourth chip 14 with the corresponding heat dissipation preset specification values, they all meet the heat dissipation specification values of the chips. However, judging from Figure 8 the operating points of the fan curves in

[0184] Reference Figure 8 As shown, the curve drawn with a solid line is the pressure difference curve of the fan 30, and the curve drawn with a double-dashed line is the operating curve of the fan 30, which is also the actual application curve of the fan 30. The operating point is the operating point of the fan in the analysis result.

[0185] The operating point of the fan in the second embodiment is close to the left end and is at a position with a relatively large slope inclination of the slow slope. The fan will have the phenomenon of unstable air pressure. The resistance of the air duct 22 system is still unbalanced, the system static pressure is relatively high, it cannot provide a high air volume, and its own consumption is relatively large. Therefore, the inlet section of the air duct 22 is optimized. Guide fins are made at the air outlet of the fan 30. Specifically, a rounded corner portion 24 is added to one end of the heat dissipation fins 21 close to the fan 30, and part of the air duct 22 on both sides of the fan 30 is made to be in a corner shape. The rounded corner portion 24 uses a large R corner for transition to avoid a 90° angle, so as to reduce the eddy current and energy loss generated when the air flow direction changes.

[0186] Embodiment Three

[0187] Reference Figure 1 And Figure 9 As shown in

[0188] Reference Figure 11As shown, the temperatures of the first chip 11, the second chip 12, the third chip 13 and the fourth chip 14 in the simulation calculation results are used as the key heat source temperatures and compared with the corresponding heat dissipation preset specification values. Referring to Table 3, the first chip 11, the second chip 12, the third chip 13 and the fourth chip 14 all have good heat dissipation effects.

[0189] Table 3

[0190] Item Heat dissipation specification value of the chip Simulation result Temperature judgment First chip 125℃ 109.06℃ Meet Second chip 12 125℃ 102.55℃ Meet Third chip 13 110℃ 104.18℃ Meet Fourth chip 14 125℃ 118.66℃ Meet

[0191] refer to Figure 10 and Figure 11 As shown, the temperatures of the first chip 11, the second chip 12, the third chip 13 and the fourth chip 14 all meet the heat dissipation specification values ​​of the chips. From the working point of the fan curve, within the optimal range, among the three embodiments of Embodiment 1, Embodiment 2 and Embodiment 3, the chip temperature in Embodiment 3 is also the lowest.

[0192] refer to Figure 10 As shown, the curve drawn by the solid line is the pressure difference curve of the fan 30, the curve drawn by the double-dash line is the working curve of the fan 30, which is also the actual application curve of the fan 30, and the working point is the working point of the fan in the analysis result.

[0193] The fan operating point of this solution is in the middle and rear section of the relatively gentle slope of the pressure difference curve, which means that the fan has strong adaptability to flow changes within a certain range. This shows that the optimized air duct system operates more stably, the fan utilization rate is improved, and the fan service life is increased.

[0194] In this application, simulation software is used to obtain the working point of the fan, and the fan status is analyzed based on the results to obtain the optimal working point. Through thermal analysis software, the working point of the fan in this solution is obtained to be within the optimal range, and the fan heat dissipation effect is improved.

[0195] In the description of the present invention, it is necessary to understand that the terms used such as “center”, “length”, “width”, “thickness”, “top”, “bottom”, “up”, “down”, “left”, “right”, “front”, “back”, “vertical”, “horizontal”, “inside”, “outside”, “axial”, “circumferential”, etc. to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred position or component must have a specific direction, a specific structure and operation, and therefore cannot be understood as limiting the present invention.

[0196] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0197] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or capable of communicating with each other; it may be directly connected, or indirectly connected through an intermediate medium, and may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0198] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0199] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. However, such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for optimizing an air duct of a heat sink of an electronic device, the electronic device comprising a circuit board assembly (10), a heat sink (20) and a fan (30), the first surface of the heat sink (20) abutting against the circuit board assembly (10), the circuit board assembly (10) comprising a chip, the second surface of the heat sink (20) comprising a plurality of heat sink fins (21), an air duct (22) being formed between two adjacent heat sink fins (21), the fan (30) being arranged on the second surface of the heat sink (20), characterized in that: The method comprises: Establishing a simulation calculation model of an electronic device including the heat sink (20) and the fan (30); Importing the simulation calculation model into simulation software; Setting simulation parameters in simulation software and performing meshing on the simulation calculation model; Setting heat source parameters for the simulation calculation model after meshing and solving it, wherein the simulation solution program iterates rapidly over time to obtain simulation calculation results that meet convergence conditions; Obtaining the operating point of the fan (30) from the simulation calculation results; According to the working point of the fan (30), the structure of the air duct (22) of the heat dissipation element (20) is adjusted until the optimal heat dissipation effect is achieved.

2. The method for optimizing the air duct of a heat sink of an electronic device according to claim 1, characterized in that: The step of obtaining the operating point of the fan (30) from the simulation calculation results specifically includes: Obtaining a pressure difference curve of the fan (30) and a system resistance curve formed when the fluid passes through the air duct (22), wherein the pressure difference curve of the fan (30) is a characteristic curve of the fan (30), and the system resistance curve formed when the fluid passes through the air duct (22) is the sum of the system resistances encountered by the fluid passing through the air duct (22); The intersection of the pressure difference curve of the fan (30) and the system resistance curve of the fluid passing through the air duct (22) is used as the working point of the fan (30).

3. The method for optimizing the air duct of a heat sink of an electronic device according to claim 1, characterized in that: In the establishment of a simulation calculation model of an electronic device including the heat sink (20) and the fan (30), the fan (30) is selected according to a required air volume value; The air volume of the fan (30) is selected to be 1.2 to 1.5 times the actual required air volume value; The actual required air volume value: q = 3600Q / (ρCpΔt), Among them, q is the actual required air volume, in m3 / h; Q is the total heat consumption of the system, in W; ρ is the air density, in kg / m3; Cp is the specific heat of air, in J / kg·℃; Δt is the temperature rise of the air, in °C.

4. The method for optimizing the air duct of a heat sink of an electronic device according to any one of claims 1 to 3, characterized in that: The gridding of the simulation calculation model comprises: Automatically segmenting the simulation calculation model into grids; Manual local mesh refinement processing is performed on the chip and the heat sink fin (21) of the simulation calculation model with automatically segmented meshes.

5. The method for optimizing the air duct of a heat sink of an electronic device according to any one of claims 1 to 3, characterized in that: After obtaining the simulation calculation results that meet the convergence conditions, the method further includes comparing the heat source temperature according to the simulation calculation results to determine whether the electronic device meets the heat dissipation requirements, specifically including: Comparing the temperature value of the chip of the circuit board assembly (10) with a preset specification value; If the temperature value of the chip is greater than the preset specification value, it is determined that the heat dissipation requirement is not met; If the temperature value of the chip is less than or equal to the preset specification value, it is determined that the heat dissipation requirement is met.

6. The method for optimizing the air duct of a heat sink of an electronic device according to any one of claims 1 to 3, characterized in that: The adjusting the structure of the air duct (22) of the heat sink (20) according to the working point of the fan (30) comprises: When the working point of the fan (30) is located at the last 1 / 3 section of the pressure difference curve of the fan (30), extending the length of the heat dissipation fin (21); When the working point of the fan (30) is located at the front 1 / 2 section of the pressure difference curve of the fan (30), a rounded corner portion (24) is added to one end of a portion of the heat dissipation fins (21) close to the fan (30), so that the portions of the air duct (22) located on both sides of the fan (30) are corner-shaped.

7. The method for optimizing the air duct of a heat sink of an electronic device according to claim 5, characterized in that: The optimal heat dissipation effect is achieved by: The electronic device meets the heat dissipation requirements, and the working point of the fan (30) is located in the last 1 / 3 section of the pressure difference curve of the fan (30), the wind pressure of the fan (30) is in the range of 1 / 5 times to 1 / 2 times the maximum static pressure of the fan (30), and the slope of the pressure difference curve of the fan (30) near the working point of the fan (30) is gentle.

8. A heat sink, characterized in that: The heat sink (20) is a heat sink (20) formed by using the heat sink air duct optimization method for electronic equipment according to any one of claims 1 to 7; One side of the heat sink (20) comprises a first heat sink area (25), a second heat sink area (26) and a mounting position (23) for accommodating a fan (30); a plurality of heat sink fins (21) are arranged in the first heat sink area (25) and the second heat sink area (26); an air duct (22) is formed between two adjacent heat sink fins (21); one end of each heat sink fin (21) faces the mounting position (23); and the other end of each heat sink fin (21) extends to a side edge of the heat sink (20).

9. The heat sink according to claim 8, characterized in that: The first heat dissipation area (25) and the installation position (23) are both located between the two second heat dissipation areas (26); The heat dissipation fin (21) located in the first heat dissipation area (25) comprises a first extension portion (211); The heat dissipation fin (21) located in the second heat dissipation area (26) comprises a second extension portion (212), a third extension portion (213) and a rounded corner portion (24); the rounded corner portion (24) is connected between the second extension portion (212) and the third extension portion (213); an extension direction of the second extension portion (212) is consistent with an extension direction of the first extension portion (211); and an angle is formed between an extension direction of the third extension portion (213) and an extension direction of the second extension portion (212).

10. An electronic device, characterized in that: The invention comprises a circuit board assembly (10), a fan (30) and a heat sink (20) as claimed in claim 9, wherein the heat sink (20) abuts against the circuit board assembly (10), and the circuit board assembly (10) comprises a plurality of chips, and positions of the plurality of chips correspond to positions of a first heat sink (25) and a second heat sink (26) of the heat sink (20).

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