Low-cost miniaturized cooling technology based on synthetic jet
Through the periodic synthetic jet and vortex ring structure driven by the synthetic jet generator and electronically controlled vibration diaphragm, the problem of efficient heat dissipation and integrated design in miniaturized equipment is solved, and the efficient and low-cost cooling effect is achieved.
Patent Information
- Application Number
- CN202510510480.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-22
- Publication Date
- 2025-07-25
AI Technical Summary
Traditional cooling technology has limitations in efficient heat dissipation and integrated design, especially in miniaturized and compact electronic devices, which is difficult to take into account both efficient heat exchange and compact design.
The synthetic jet generator is used to form a periodic synthetic jet and vortex ring driven by an electronically controlled vibrating diaphragm, and the heat exchange effect is enhanced by the flow characteristics, and the low-cost cooling is achieved with a simple structure.
It achieves high-efficiency cooling, low-cost, simple structure and high reliability cooling effects, and is suitable for miniaturized electronic equipment.
Smart Images
Figure CN120379210A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of electronic component cooling, and particularly relates to a low-cost miniaturized cooling technology based on synthetic jets. Background Art
[0002] The rapid development of electronic component technology has led to a continuous increase in the thermal power density, and the heat dissipation demand has also increased accordingly. However, while pursuing high-efficiency heat dissipation, existing cooling technologies face severe challenges in space constraints and integrated design. This contradiction is particularly prominent in miniaturized and compact electronic devices, where traditional cooling methods are difficult to balance high-efficiency heat transfer and compact design. Therefore, developing a new cooling technology with higher cooling efficiency and suitable for space-constrained conditions has become an urgent problem to be solved. Based on this background, an innovative cooling technology using an electro-controlled vibrating diaphragm to form synthetic jets is proposed, which realizes enhanced heat transfer for high-power density electronic components and provides a solution for miniaturization and high-efficiency heat dissipation.
[0003] Traditionally, the heat dissipation technologies for electronic components can be roughly divided into two categories: passive heat dissipation represented by natural convection, heat pipes, boiling heat transfer, etc., and active heat dissipation represented by fan heat transfer, spray cooling, microchannel cooling, and jet impingement heat transfer. Among them, the ability of passive heat dissipation has become insufficient in the face of the increasing cooling demand, and the active heat dissipation technology with stronger cooling ability has become the mainstream. Therefore, the relevant principles of the above four active heat dissipation technologies will be briefly introduced as follows:
[0004] 1. Fan heat transfer. Fan heat transfer removes heat through air flow in a forced convection manner, and has the characteristics of simple structure, low cost, and wide application. However, due to the limited heat capacity of air, its heat dissipation ability is often insufficient in high-power density scenarios, and it is difficult to meet the requirements of highly integrated design. In addition, noise and vibration problems will also occur during the operation of the fan, affecting the system performance.
[0005] 2. Spray cooling. Spray cooling uses a nozzle to spray the coolant onto the high heat flux density surface in the form of fine droplets. A large amount of heat is carried away when the coolant evaporates, realizing high-efficiency heat transfer. This method has high cooling efficiency and is suitable for extreme heat dissipation requirements, but the system is complex and liquid management and potential corrosion problems need to be solved. However, in the application of electronic component heat dissipation, since the component temperature usually does not exceed 100 degrees Celsius, it is difficult to effectively drive the phase change process of spray cooling, thus reducing the actual performance of this technology.
[0006] 3. Microchannel Cooling. Microchannel cooling involves machining tiny channel structures on the surface of electronic components or their heat dissipation substrates. By utilizing the flow of coolant within the channels to carry away heat, high - efficiency heat dissipation is achieved. This technology offers extremely high heat transfer efficiency and the advantage of a compact design, making it highly suitable for the heat dissipation requirements of high - power - density and miniaturized devices. However, microchannel cooling also has significant drawbacks in practical applications: Firstly, its manufacturing process is complex, with high requirements for materials and precision, resulting in high costs. Secondly, the microchannel structure is prone to blockage due to impurities, bubbles, or particles in the coolant, affecting the long - term stability and heat dissipation performance of the system. In addition, to maintain the circulation and flow rate of the coolant, the system usually requires high - performance pumps, increasing energy consumption and system complexity. Meanwhile, the leakage or corrosion of the coolant may also pose a potential threat to the reliability of electronic components.
[0007] 4. Jet Impingement Heat Transfer. By directly impinging a high - velocity jet on a hot surface, the local heat transfer effect is enhanced, featuring strong local cooling ability and being applicable to areas that require key heat dissipation. This technology can achieve relatively high heat dissipation efficiency, but when applied, it is necessary to balance the relationship between the jet impingement intensity and energy consumption. Traditional steady - state jet impingement heat transfer technology usually relies on a pump - pressure system to increase the pressure of the cooling medium to form a stable jet, and requires supporting pump - pressure equipment and a conveying system. Due to the complex system design involving multiple additional components, this technology is difficult to meet the requirements of highly integrated and compact designs for cooling devices, while increasing the energy consumption and maintenance costs of the system.
[0008] Therefore, traditional cooling technologies have significant limitations in terms of high - efficiency heat dissipation and integrated design. Summary of the Invention
[0009] The present invention aims to provide a low - cost and miniaturized cooling technology based on synthetic jets, aiming to solve the technical problems existing in the prior art.
[0010] To achieve the above object, the present invention provides the following technical solution: a low - cost and miniaturized cooling technology based on synthetic jets. A synthetic jet generator is axially installed on a columnar component to be cooled. The synthetic jet generator ejects synthetic jets, periodically forming jet columns and accompanying vortex rings to dissipate heat from the columnar component to be cooled. The installed synthetic jet generator includes a housing and an electronically controlled diaphragm disposed on one side of the housing. A jet orifice is provided on the side of the housing opposite to the side where the electronically controlled diaphragm is disposed.
[0011] In another preferred embodiment of the present invention, the jet orifice is directly opposite to the columnar component to be cooled, and the jet orifice is coaxially arranged with the columnar component to be cooled. The ratio of the diameter of the jet orifice to the diameter of the columnar component to be cooled is 0.5 - 1.5.
[0012] In another preferred embodiment of the present invention, the stroke ratio formula of the jet column is L / D = ΔV / (πD 3 / 4), and the stroke ratio is less than 3.
[0013] In another preferred embodiment of the present invention, the housing of the synthetic jet generator can be deformed; the volume can change with the oscillation of the electro-controlled diaphragm.
[0014] In another preferred embodiment of the present invention, the side of the housing where the electro-controlled diaphragm is arranged is a flexible layer.
[0015] In another preferred embodiment of the present invention, numerical simulation is carried out to compare the heat transfer efficiency of the steady jet and the single-period synthetic jet. The numerical simulations of the two jet forms adopt the same jet velocity, and it is assumed that the energy consumed for injecting the same mass flow rate is equal. The heat transfer efficiency ratio of the single-period synthetic jet to the steady jet is defined as [∫(P2(t)-P0)dt / (L / D1)] / [(P1(t)-P0)t1 / (L / D2)].
[0016] The electro-controlled diaphragm in the synthetic jet generator generates periodic vibrations under the drive of a periodic voltage signal, causing the volume of the internal cavity of the generator to change periodically. When the cavity volume increases, fluid is inhaled from the outside; when the cavity volume decreases, fluid is ejected to the outside, thus forming a synthetic jet with unsteady characteristics.
[0017] Affected by the flow characteristics, during the process of the cavity inhaling fluid, the external environmental fluid near the outlet of the synthetic jet generator will be evenly inhaled without a fixed direction; while during the process of the cavity discharging fluid, the fluid is approximately ejected in a directional manner along the axial direction, forming a jet liquid column with a diameter equivalent to the opening diameter of the outlet of the synthetic jet generator.
[0018] During the process of the synthetic jet generator cavity volume decreasing and ejecting the jet, the shear layer of the jet will roll up to form a vortex ring structure. The periodically generated vortex rings move downstream under the drive of the self-induced velocity and interact with the wall surface of the columnar heat dissipation component with a diameter of d, significantly enhancing the heat transfer effect.
[0019] The vortex rings form an induced velocity field under the action of viscosity and interact with the columnar wall surface through this velocity field. The induced velocity field accelerates the flow of the environmental fluid near the columnar wall surface, directly enhancing the intensity of convective heat transfer; the rotational induced velocity field of the vortex rings transports the low-temperature environmental fluid in the far field to the vicinity of the columnar wall surface, and at the same time entrains and removes the high-temperature fluid near the wall surface, significantly increasing the temperature difference between the columnar wall surface and the surrounding environment, thereby further enhancing the heat transfer effect.
[0020] The above interactions enhance the heat dissipation performance of the columnar heat-dissipating component through the following two mechanisms: the first mechanism is the core mechanism of the traditional jet impingement heat dissipation technology; the second mechanism makes full use of the unsteady characteristics accompanied by the formation of vortex rings in the synthetic jet, demonstrating a more excellent heat dissipation effect, and the unsteady characteristics greatly improve the overall heat dissipation efficiency.
[0021] Under the drive of the electronically controlled diaphragm, the maximum volume change of the cavity of the synthetic jet generator is ΔV. Thus, the length of the ejected jet liquid column can be calculated as L = ΔV / (πD 2 / 4). According to the stroke ratio formula of the jet ratio L / D = ΔV / (πD 3 / 4), and controlling it within a range not exceeding 3 can meet the criterion for the best formation of vortex rings to achieve a higher heat transfer efficiency.
[0022] Advantages of the present invention:
[0023] 1. Balancing high integration and low cost. By combining a simple electronically controlled diaphragm with a small cavity to generate a synthetic jet for cooling electronic components, without a complex flow supply system, it not only meets the requirements of highly integrated design but also has the significant advantage of low cost, and is suitable for the cooling application of miniaturized electronic devices.
[0024] 2. Simple structure and high reliability. The cooling device of this patent is only composed of a small cavity formed by an electronically controlled diaphragm and a fixed wall surface, with an extremely simple design structure and low technical implementation difficulty. Due to fewer components and stable stress, the failure rate during the operation of the device is low, and the overall reliability is significantly improved.
[0025] 3. Making full use of flow characteristics to improve heat transfer efficiency. The coaxial arrangement of the synthetic jet and the columnar heat-dissipating component makes full use of the unsteady characteristics of the flow, that is, the fluid entrainment ability of the vortex rings periodically formed by the synthetic jet, effectively enhancing the perturbation of the thermal boundary layer, greatly improving the heat transfer efficiency, and enhancing the heat transfer capacity.
[0026] 4. Without additional cooling working medium. Directly driving the ambient fluid to form a synthetic jet without the input of a cooling working medium, on the one hand, it reduces the complexity of the cooling device as a whole, and on the other hand, it also avoids the need to solve problems such as the corrosion of electronic components by the cooling working medium.
[0027] In summary, in order to optimize the limitations of traditional cooling technologies in terms of high-efficiency heat dissipation and integrated design, the present invention combines an electronically controlled diaphragm with a small cavity to generate a synthetic jet, thereby realizing a cooling technology with high integration and low cost. By arranging the synthetic jet coaxially with the columnar heat-dissipating component, giving full play to the fluid entrainment ability of the periodic vortex rings of the synthetic jet, significantly enhancing the perturbation of the thermal boundary layer of electronic components, and then greatly improving the heat transfer efficiency to achieve high-efficiency heat dissipation in miniaturized devices.
[0028] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, in which:
[0030] Figure 1 is a schematic application diagram of an embodiment of the present application.
[0031] Figure 2 is the formation principle of a synthetic jet and its accompanying vortex ring structure in an embodiment of the present application.
[0032] Figure 3 is a schematic diagram of the coaxial vortex ring-cylindrical interaction process in an embodiment of the present application.
[0033] Figure 4 is the variation law of the heat dissipation efficiency ratio with the single-cycle stroke ratio based on the heat dissipation power of the steady jet in the numerical simulation of this embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0034] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present invention and should not be construed as limiting the present invention.
[0035] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "vertical", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.
[0036] In the description of the present invention, unless otherwise specified and defined, it should be noted that the terms "mounted", "connected", and "connected" should be understood in a broad sense. For example, they can be mechanical connections or electrical connections, or the communication inside two elements. They can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.
[0037] The present invention provides a low-cost miniaturized cooling technology based on synthetic jets, such asFigure 1 As shown in the figure, a synthetic jet generator is installed around the columnar heat-dissipating component. The synthetic jet generator is located directly above the columnar heat-dissipating component, and generates a synthetic jet coaxial with the columnar heat-dissipating component to enhance the heat transfer effect.
[0038] The synthetic jet generator includes a cavity and an electronically controlled vibrating diaphragm. The electronically controlled vibrating diaphragm is arranged on the top surface of the cavity. A jet orifice is provided at the bottom of the cavity. The jet orifice faces the columnar heat-dissipating component and is coaxially arranged with the columnar heat-dissipating component. The ratio of the diameter of the jet orifice to the diameter of the columnar heat-dissipating component is 0.5 - 1.5. The housing of the synthetic jet generator can be deformed, and the side of the housing where the electronically controlled vibrating diaphragm is arranged is a flexible layer.
[0039] Under the drive of the electronically controlled vibrating diaphragm, the maximum volume change of the cavity of the synthetic jet generator is ΔV. Thus, the length of the ejected jet liquid column can be calculated as L = ΔV / (πD 2 / 4). Based on this, the key parameter of the jet - the stroke ratio L / D = ΔV / (πD 3 / 4), that is, the aspect ratio of the jet liquid column. In this embodiment, controlling the stroke ratio L / D within a range not exceeding 3 can meet the criterion for the best formation of the vortex ring and achieve a higher heat transfer efficiency.
[0040] As Figure 2 shown, the electronically controlled vibrating diaphragm in the synthetic jet generator generates periodic vibrations under the drive of a periodic voltage signal, causing the volume of the internal cavity of the generator to change periodically. When the cavity volume increases, fluid is inhaled from the outside; when the cavity volume decreases, fluid is ejected to the outside, thus forming a synthetic jet with unsteady characteristics.
[0041] As Figure 3 shown, during the process of the cavity volume of the synthetic jet generator decreasing and ejecting the jet, the shear layer of the jet will roll up to form a vortex ring structure. The periodically generated vortex rings move downstream under the drive of the self - induced velocity and interact with the wall surface of the columnar heat - dissipating component with a diameter of d, significantly enhancing the heat transfer effect.
[0042] Numerical simulation and simulation:
[0043] In order to reflect the high - efficiency heat transfer advantage of this embodiment, relevant numerical simulations were carried out to compare and analyze the performance differences between the steady - state jet and the single - cycle synthetic jet during the interaction with the constant - temperature columnar wall surface.
[0044] Through simulation and solution, the following data were obtained: the steady - state heat dissipation power P0 of the constant - temperature columnar wall surface under the condition of no jet impact; the change process P1(t) of the heat dissipation power of the constant - temperature columnar wall surface during the steady - state jet impact; and the change process P2(t) of the heat dissipation power of the constant - temperature columnar wall surface during the single - cycle synthetic jet impact.
[0045] Compare the heat transfer efficiency of the steady jet and the single - cycle synthetic jet. For the numerical simulations of the two jet forms, the same jet velocity is adopted, and it is assumed that the energies consumed for injecting the same mass flow rate are equal. On this basis, define the heat transfer efficiency ratio of the single - cycle synthetic jet to the steady jet as
[0046]
[0047] wherein, L / D1 and L / D2 are the stroke ratios of the single - cycle synthetic jet and the steady jet respectively, that is, the aspect ratio of the length to the diameter of the jet - discharged liquid column. L / D2 is selected as the stroke ratio corresponding to the stable stage of the heat transfer efficiency of the steady jet, and the corresponding duration is t1. By calculating this efficiency ratio, the advantage of this embodiment over the traditional steady jet in heat dissipation performance can be intuitively quantified. The stroke ratio of the single - cycle synthetic jet is selected to be between 1 and 5, and the trend of the calculated efficiency ratio changing with the stroke ratio is as Figure 4 shown.
[0048] The overall efficiency ratio is greater than 1, which proves that the synthetic jet applied in this embodiment has a higher heat transfer efficiency than the steady jet impact. Secondly, the variation law of the efficiency ratio shows different trends in two intervals where the stroke ratio is less than 3 and greater than 3: when the stroke ratio is less than 3, the efficiency ratio decreases with the increase of the stroke ratio, indicating that the advantage brought by the unsteady effect gradually weakens; when the stroke ratio is greater than 3, the efficiency ratio tends to 1.5. Considering the application effect, to ensure the best heat dissipation effect, the stroke ratio L / D in this embodiment is controlled within a range not exceeding 3.
[0049] In the description of this specification, the descriptions referring to terms such as "preferred embodiment", "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above - mentioned terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.
[0050] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and purposes of the present invention. The scope of the present invention is defined by the claims and their equivalents.
Claims
1. Low-cost miniaturized cooling technology based on synthetic jets, characterized in that: Axially install a synthetic jet generator on the columnar component to be cooled. Eject a synthetic jet through the synthetic jet generator to periodically form a jet column and accompanying vortex rings, so as to cool the columnar component to be cooled; the installed synthetic jet generator includes a housing and an electronically controlled diaphragm disposed on one side of the housing, and a jet orifice is provided on the side of the housing opposite to the side where the electronically controlled diaphragm is disposed.
2. The low-cost miniaturized cooling technology based on synthetic jet according to claim 1, wherein: The jet orifice faces the columnar component to be cooled, and the jet orifice is coaxially arranged with the columnar component to be cooled. The ratio of the diameter of the jet orifice to the diameter of the columnar component to be cooled is 0.5 - 1.
5.
3. The low-cost miniaturized cooling technology based on synthetic jet according to claim 2, characterized in that: The stroke ratio formula of the jet column is L / D = ΔV / (πD 3 / 4), and the stroke ratio is less than 3.
4. The low-cost miniaturized cooling technology based on synthetic jet according to claim 3, characterized in that: The housing of the synthetic jet generator can be deformed.
5. The low-cost miniaturized cooling technology based on synthetic jet according to claim 4, wherein: The side of the housing where the electronically controlled diaphragm is disposed is a flexible layer.
6. The low-cost miniaturized cooling technology based on synthetic jets according to claim 5, characterized in that: Perform numerical simulation and comparison of the heat transfer efficiency between steady jet and single - cycle synthetic jet. The numerical simulations of the two jet forms use the same jet velocity, and it is assumed that the energy consumed for ejecting the same mass flow rate is equal. Define the heat transfer efficiency ratio of the single - cycle synthetic jet to the steady jet as [∫(P2(t) - P0)dt / (L / D1)] / [(P1(t) - P0)t1 / (L / D2)].