A method for enhancing heat exchange by using synthetic double jet self-feeding effect to realize high-frequency disturbance

Abstract

The application provides a high-frequency disturbance reinforced heat exchange method using a synthetic double jet self-acting effect, and relates to the technical field of electronic component heat management reinforced heat exchange. The application determines local high-temperature hot spots and characteristic lengths through simulation or temperature measurement, arranges a pair of jet flow channels and vibration elements in the hot spot area and forms left and right cavities, generates frequency-doubled oscillating jet flow under periodic driving, adjusts the jet flow spacing, the channel width and the vibration element size according to the formation criterion, makes the dimensionless parameter in the self-acting range, forms a strong vortex area covering 360 degrees around the hot spot, so as to realize high-frequency accurate cooling of the local hot spot and significantly improve the local convective heat exchange coefficient.

Description

Technical Field

[0001] This invention relates to the field of enhanced heat transfer technology for thermal management of electronic components, and in particular to an enhanced heat transfer method that utilizes the self-sufficiency effect of synthetic dual jets to achieve high-frequency disturbances. Background Technology

[0002] With the rapid development of electronic components towards higher power, the integration and power consumption of core electronic components such as chips continue to rise, resulting in highly concentrated localized heat flux. If these localized high-temperature areas cannot be efficiently cooled in a timely manner, it will restrict the performance stability and lifespan of electronic devices. Statistics show that for every 10°C increase in localized temperature, component reliability decreases by 50%. Therefore, efficient heat exchange in localized high-temperature areas of electronic components has become a core requirement for overcoming the current bottlenecks in thermal management of electronic devices. Existing electronic components have significant shortcomings in their heat exchange capabilities for localized high-temperature areas, making it difficult to meet the heat dissipation requirements of high localized heat flux densities. Specific problems are as follows: (1) Insufficient local adaptability and limited heat exchange efficiency: Existing needle-fin heat sinks mostly adopt a uniform array design, which is insufficient in coverage and fit of local high-temperature areas. They cannot specifically enhance the heat conduction of hot spots and cannot adapt to the local heat dissipation needs of high-power electronic components.

[0003] (2) Local heat dissipation is lacking, uneven heat dissipation and slow speed: Current condensing devices, air-cooled heat sinks and other devices mostly use the whole component as the heat dissipation object, which is difficult to accurately act on local high temperature areas. Either the temperature remains high because the hot area does not receive targeted heat exchange, or the non-high temperature area is over-cooled, resulting in energy waste. Moreover, the heat dissipation speed is far behind the heat generation rate of the local high temperature area, which easily leads to heat accumulation.

[0004] (3) Insufficient high-frequency heat exchange capacity, local heat cannot be transferred in time: The heat in local high-temperature areas has the characteristics of "instantaneous concentration and continuous generation", and high-frequency continuous heat exchange is required to avoid heat accumulation. Existing heat dissipation devices such as traditional fans or low-frequency pulse heat exchangers generally have a heat exchange frequency of less than 100Hz and a low convective heat transfer coefficient, which cannot match the heat generation rhythm of local high-temperature areas, making it difficult for the hot spot temperature to drop to the safe range quickly.

[0005] In summary, how to develop a precise, targeted, high-frequency, and high-heat-exchange cooling method for electronic components, addressing the challenges of rapid heat dissipation in localized hot spots, has become a critical issue that urgently needs to be addressed in the field of thermal management for electronic devices. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a method for enhanced heat transfer by utilizing the self-sufficiency effect of synthetic dual jets to achieve high-frequency disturbance, which can implement precise targeted high-frequency enhanced heat transfer on local high-temperature hot spots and form a stable strong disturbance flow around the hot spots to accelerate heat transfer.

[0007] To achieve the above objectives, the present invention provides the following solution: A method for enhancing heat transfer by utilizing the self-sufficiency effect of synthetic dual jets to achieve high-frequency disturbances includes: The location and characteristic length of local high-temperature hot spots in electronic components are determined by simulation verification or temperature measurement, and the hot spot region is determined based on the location and characteristic length of the local high-temperature hot spots; A pair of jet channels facing the hot spot are arranged in the hot spot area. A vibrating element is arranged between the two jet channels so that the vibration direction of the vibrating element is perpendicular to the jet spray direction. A solid is arranged to connect the jet channels and the vibrating element so that the solid forms two cavities on the left and right. Only the two jet channels in the left and right cavities exchange mass and energy with the outside world, so that the working fluid exchanges back and forth between the left and right cavities and the external flow field through the two jet channels. The vibrating element located upstream of the two jet channels is driven to vibrate periodically at a preset input frequency using a periodic driving method, causing the fluid in the left and right chambers to oscillate in volume, and forming two jet nozzles at the outlets of the two jet channels, and forming an oscillating jet at the two jet nozzles with the same preset input frequency; after the two oscillating jets are coupled, the actual vibration frequency is twice the preset input frequency. Based on the formation criteria of the self-sufficient phenomenon of synthetic double jets, the spacing between the two jet channels, the width of the jet channels, and the vibration element are adjusted, and the dimensionless parameters are calculated based on the parameters of each element. When the dimensionless parameters do not meet the formation criteria, the diameter of the vibrating element is increased, the width of the jet channel is reduced, and the distance between the two jet channels is decreased, so that the dimensionless parameters are controlled within the self-sufficiency range, thereby generating a strong vortex region covering 360° around the hot spot in the oscillating jet.

[0008] Preferably, the spacing between the two jet channels, the width of the jet channels, and the vibrating element are adjusted according to the formation criteria of the synthetic dual-jet self-sufficiency phenomenon, and dimensionless parameters are calculated based on the parameters of each element, including: Define the dimensionless parameter as S tk ; S is calculated based on the spacing between the two jet channels, the width of the jet channels, the structural parameters of the vibrating element, and the preset input frequency. tk .

[0009] Preferably, the method further includes adjusting the spacing between the two jet channels, the width of the jet channels, and the vibrating element according to the formation criteria of the synthetic dual-jet self-sufficiency phenomenon, and calculating dimensionless parameters based on the parameters of each element. The formation criterion is limited to S. tk Greater than 420; Limit self-sufficiency to S tk Greater than 420.

[0010] Preferably, when the dimensionless parameter does not meet the formation criteria, increasing the diameter of the vibrating element, decreasing the width of the jet channel, and decreasing the distance between the two jet channels includes: While keeping the preset input frequency constant, first reduce the width of the jet channel; Increase the diameter of the vibrating element after reducing the width of the jet channel; After increasing the diameter of the vibrating element, the distance between the two jet channels is reduced so that the dimensionless parameters meet the formation criteria.

[0011] Preferably, a periodic driving method is used to drive a vibrating element located upstream of the two jet channels to vibrate periodically at a preset input frequency, including: A periodic drive signal is applied to the vibrating element; The frequency of the periodic drive signal is made to match the preset input frequency in order to drive the vibrating element to generate periodic vibration.

[0012] Preferably, applying a periodic drive signal to the vibrating element includes: Set the periodic drive signal to a periodically changing voltage signal; Periodic vibrations are generated by driving a vibrating element through a periodically changing voltage signal.

[0013] Preferably, the vibrating element is a piezoelectric diaphragm; the piezoelectric diaphragm vibrates periodically at a preset input frequency to cause volumetric oscillations in the fluid within the left and right cavities.

[0014] Preferably, the inner walls of the left and right cavities are smooth; the cavity volumes of the left and right cavities are adapted to the vibration stroke of the vibrating element to form volumetric oscillation.

[0015] Preferably, a periodic driving method is used to drive a vibrating element located upstream of the two jet channels to vibrate periodically at a preset input frequency, including: The preset input frequency is limited to 300Hz to 900Hz; Under the condition of a preset input frequency of 300Hz to 900Hz, the actual vibration frequency after the two oscillating jets are coupled is twice the preset input frequency.

[0016] Preferably, the process of achieving an actual vibration frequency that is twice the preset input frequency after coupling of the two oscillating jets includes: When the vibrating element vibrates periodically at a preset input frequency, the fluid velocity on both sides of the vibrating element has an opposite phase difference, so that the fluid in the left and right chambers is in the state of discharge and intake at the same time. Under the action of discharge and intake, the fluid velocities at the two jet nozzles are in opposite directions, and the pressures in the left and right chambers are opposite. When the distance between the two jet channels satisfies the jet interaction condition, the fluid on the discharge side is deflected and accelerated under the influence of the fluid on the suction side, and is further drawn into the suction cavity, thereby forming a stable periodic self-sufficient flow that can be maintained without jet replenishment, so as to achieve the coupling of the two oscillating jets and make the actual vibration frequency of the entire device twice the preset input frequency.

[0017] The present invention discloses the following technical effects: This invention determines the location and characteristic length of localized high-temperature hotspots in electronic components through simulation verification or temperature measurement, and accordingly identifies the hotspot region. A pair of jet channels facing the hotspot are then arranged within this region, matching the heat transfer range to the spatial scale of the hotspot, thus achieving precise targeted cooling of the localized high-temperature area. Compared to the shortcomings of uniform array heat sinks in terms of insufficient coverage and fit to hotspots, this invention concentrates heat transfer capacity on the hotspot, reducing ineffective cooling and resource dispersion in non-high-temperature areas, and improving the effective heat transfer intensity and local adaptability of the hotspot region.

[0018] This invention arranges a vibrating element between two jet channels, forming two cavities enclosed by a solid structure. These cavities exchange mass and energy with the outside environment solely through the two jet channels. Under periodic driving, the fluid within the cavities undergoes volumetric oscillation. The working fluid reciprocates between the cavities and the external flow field via the two jet channels, forming an oscillating jet at the nozzles. This creates a continuous and repeatable localized disturbance heat transfer process near the hotspot, rapidly refreshing the fluid boundary layer around the hotspot and increasing the convective heat transfer coefficient. Mechanistically, this overcomes the problems of existing overall heat dissipation methods, such as difficulty in precisely targeting localized high-temperature areas, uneven heat dissipation, and delayed response, making it easier to promptly bring the hotspot temperature back to a safe range.

[0019] This invention also utilizes the coupling of two oscillating jets to achieve an actual vibration frequency twice the preset input frequency. Based on the formation criteria of the self-sufficient phenomenon of the synthesized dual jets, the distance between the two jet channels, the width of the jet channels, and the vibration element are adjusted. When the dimensionless parameters do not meet the formation criteria, the dimensionless parameters are controlled within the self-sufficient range by increasing the diameter of the vibration element, decreasing the width of the jet channels, and decreasing the distance between the two jet channels, thereby forming a strong vortex region covering 360° around the hot spot. This high-frequency disturbance superposition and strong vortex coverage enhances the ability to rapidly remove instantaneous heat and suppresses heat accumulation, better matching the heat generation rhythm of "instantaneous concentration and continuous generation" of local heat flux density, thus compensating for the shortcomings of existing low-frequency heat exchange capabilities and the inability to follow changes in the hot spot's heat load. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A flowchart of the method provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the relationship curves and working ranges provided for embodiments of the present invention; Figure 3 This is a schematic diagram of the piezoelectric synthetic dual-jet exciter structure provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the velocity scaling in the simulation calculation of the self-sufficiency effect of the synthetic dual-jet provided in the embodiments of the present invention; Figure 5 This is a schematic diagram of the velocity cloud map during the initial formation of the self-sufficiency phenomenon provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the velocity cloud during heat transfer to a hot spot by a self-generated eddy current, provided in an embodiment of the present invention. Figure 7 This is a schematic diagram of the velocity cloud map during heat exchange when the jet merges with the external flow field, provided in an embodiment of the present invention. Figure 8 This is a schematic diagram of the velocity cloud during the reverse self-formation process provided in an embodiment of the present invention. Detailed Implementation

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

[0023] The purpose of this invention is to provide a method for enhancing heat transfer by utilizing the self-sufficiency effect of synthetic dual jets to achieve high-frequency disturbances. This method can construct a high-frequency oscillating jet and a strong vortex action zone covering 360° in the hot spot area, thereby improving local heat transfer capacity and reducing the risk of hot spot temperature accumulation.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Figure 1 The method flowchart provided in the embodiments of the present invention is as follows: Figure 1 As shown, this invention provides a method for enhancing heat transfer by utilizing the self-sufficiency effect of synthetic dual jets to achieve high-frequency disturbances, comprising: Step 100: Use simulation verification or temperature measurement to determine the location and characteristic length of local high-temperature hot spots in electronic components, and determine the hot spot region based on the location and characteristic length of local high-temperature hot spots; Step 200: Arrange a pair of jet channels facing the hot spot in the hot spot area, arrange a vibrating element between the two jet channels so that the vibration direction of the vibrating element is perpendicular to the jet spray direction, arrange a solid connecting the jet channels and the vibrating element so that the solid forms two cavities, left and right. The two cavities exchange mass and energy with the outside world only through the two jet channels, so that the working fluid exchanges back and forth between the two cavities and the external flow field through the two jet channels. Step 300: The vibrating element located upstream of the two jet channels is driven to vibrate periodically at a preset input frequency using a periodic driving method, so that the fluid in the left and right chambers generates volume oscillation, and two jet nozzles are formed at the outlet of the two jet channels, and an oscillating jet with the same preset input frequency is formed at the two jet nozzles; the actual vibration frequency after the two oscillating jets are coupled is twice the preset input frequency. Step 400: Adjust the spacing between the two jet channels, the width of the jet channels, and the vibration element according to the formation criteria of the synthetic double jet self-sufficiency phenomenon, and calculate the dimensionless parameters based on the parameters of each element. Step 500: When the dimensionless parameters do not meet the formation criteria, increase the diameter of the vibrating element, decrease the width of the jet channel, and decrease the distance between the two jet channels to control the dimensionless parameters within the self-sufficiency range, thereby generating a strong vortex region covering 360° around the hot spot in the oscillating jet.

[0026] Specifically, the working principle of this embodiment is as follows: After the device is started, the exciter generates an inverse piezoelectric effect under the drive of a periodic voltage signal, driving the vibrating diaphragm to vibrate reciprocally, converting the input electrical energy into the kinetic energy of the diaphragm vibration; the reciprocating vibration of the diaphragm causes the left and right cavities to alternately compress and expand, forming volumetric oscillation, and the fluid is periodically discharged and drawn in at the two jet outlets, applying excitation disturbance to the external flow field. When the velocities on both sides of the vibrating diaphragm are out of phase, one cavity is in the discharge state while the other cavity is in the suction state; under the condition that the distance between the two jet outlets is small, the discharge jet is deflected and accelerated by the fluid induced by the suction side. After the deflected jet further develops, it is drawn into the suction side and flows back to the suction cavity, thus forming a self-sufficient synthetic dual jet. After entering the self-sufficient state, the velocities on both sides of the vibrating diaphragm are out of phase, the velocities at the two jet outlets are in opposite directions, the pressures in the two cavities are opposite, and a stable periodic self-sufficient flow can be maintained without the need for continuous external replenishment of jets.

[0027] Furthermore, this embodiment explicitly proposes the formation criteria for the self-sufficiency effect and defines a dimensionless parameter. , , among which, U avg The average velocity of the jet at the jet outlet is used to characterize the equivalent velocity order of the jet under the periodic drive of the vibrating diaphragm, and is used to calculate the dimensionless parameter S. tk The characteristic velocity used to quantify the jet momentum input is f, where f is the diaphragm frequency, a is the jet outlet width, and s is the distance between the two jet outlets. Let π be the mathematical constant, A be the amplitude of the diaphragm, R be the radius of the diaphragm, and 2R be the diameter of the diaphragm.

[0028] like Figure 2 As shown in the figure, this embodiment indicates that the regions forming the impact jet are regions II and III, corresponding to 115. tk <420, Region IV is the region that forms a self-sufficient system, that is, when S tk When the value is greater than 420, the self-sufficiency phenomenon is considered to be more obvious.

[0029] This embodiment is a creative transformation based on the "self-supporting phenomenon of dual-synthetic jets"—by "optimizing the jet direction towards the hot spot + nozzle spacing," S tk The "jet-free backflow zone" at >420° transforms into a "360° strong vortex heat transfer field".

[0030] ​In a preferred embodiment, the enhanced heat transfer method for high-frequency disturbances using the self-sufficiency effect of synthetic dual jets provided by the present invention first obtains the overall heat distribution of electronic components during the design or operation phase of electronic devices through simulation verification and temperature measurement, determines the location of local high-temperature hot spots of core electronic components such as chips and the characteristic length matching the hot spot size, thereby spatially delineating the hot spot areas that need to be cooled, providing a basis for subsequent jet structure layout and parameter design.

[0031] In terms of geometric arrangement, the present invention arranges a pair of jet channels facing the hot spot near the hot spot area, and arranges a vibrating element between the two jet channels, with the vibration direction of the vibrating element perpendicular to the jet jet direction; the jet channels and the vibrating element are connected by solid material to form two closed cavities on the left and right, which exchange mass and energy with the external flow field only through the jet channels. The working fluid reciprocates between the cavity and the external flow field through the jet channels, thereby providing a fluid basis for the subsequent high-frequency oscillating jet.

[0032] In terms of drive and energy conversion, the present invention uses piezoelectric excitation, electromechanical drive or other periodic drive methods to make the vibrating element located upstream of the jet channel generate stable periodic vibration at a preset input frequency, which efficiently converts the input electrical energy or mechanical energy into periodic volume oscillation of the fluid in the cavity; the reciprocating motion of the vibrating element causes the left and right cavities to alternately compress and expand, and the cavity volume changes periodically with time. As a result, the working fluid exhibits periodic discharge and intake at the two jet outlets, thereby forming a continuous high-frequency disturbance flow field near the hot spot of the electronic component.

[0033] Regarding high-frequency oscillation and frequency doubling effect, the present invention further applies periodic vibration with a frequency of f to the vibrating element. Under the drive of this vibration, the volumes of the left and right cavities oscillate with time at the same frequency, forming oscillating jets with a frequency of f at the two jet nozzles respectively. Due to the interaction between the volume change of the left and right cavities and the jets, the two oscillating jets are coupled in space, making the entire jet device exhibit the characteristic that the actual vibration frequency is twice the input driving frequency. Thus, an effective disturbance frequency higher than the external driving frequency is obtained in the hot spot area, which significantly enhances the ability of vortex generation and thermal boundary layer destruction in the convective heat transfer process.

[0034] Regarding parameter design and self-sufficiency conditions, this invention adjusts the nozzle spacing, nozzle width, and geometric parameters of the vibrating element to achieve the formation conditions S of the synthetic dual-jet self-sufficiency phenomenon. tk >420 is used as the design criterion; when the dimensionless parameter S is calculated based on various geometric and operating parameters... tk When the value is less than 420, iterative adjustments are made by increasing the diameter of the vibrating element, decreasing the width of the jet channel, and decreasing the distance between the two jet channels, where S tkThe sensitivity to jet channel width, diaphragm diameter, and distance between two jet channels, in descending order, is: jet channel width, diaphragm diameter, and distance between two jet channels. Through the matching of these parameters, the dimensionless parameter S is optimized. tk Confined to its self-sufficient operating range, the oscillating jet forms a strong vortex structure covering 360° around the hot spot, achieving precise cooling of the local high-temperature area with high frequency and strong disturbance. Under the same operating conditions, the local convective heat transfer coefficient of the hot spot area can be increased to several times that of the baseline state.

[0035] In terms of overall system performance and applicability, this invention utilizes the self-sufficiency effect of the dual jets to generate and maintain oscillating jets. The oscillation process relies entirely on the pressure differential distribution of the working fluid and the geometric feedback of the cavity, eliminating the need for additional complex mechanical rotating components. By adjusting operating parameters such as driving frequency, amplitude, and flow distribution, a flexible trade-off can be achieved between the degree of heat transfer enhancement and additional pressure drop and energy consumption, balancing high performance and low cost. This method is applicable to local hot spot cooling scenarios for electronic components of different power levels and packaging forms. The specific implementation of the synthetic dual jet self-sufficiency phenomenon can employ piezoelectric vibrating membranes, microelectromechanical actuators, or other structures capable of providing periodic volumetric oscillations, all of which can be included in the application scope of the heat transfer enhancement method for high-frequency disturbances proposed in this invention, utilizing the self-sufficiency effect of synthetic dual jets.

[0036] In another preferred embodiment, this embodiment employs a piezoelectric synthetic dual-jet exciter to achieve the dual-jet self-sufficiency effect. In this embodiment, the dual-jet channels are symmetrically arranged on both sides of the local high-temperature region of the electronic component, with the jet direction facing the region where the electronic component is located. The two jet channels have the same aperture, are arranged in a straight line, and the inner walls of the channels are polished to reduce the flow resistance of the working fluid, thereby reducing the additional pressure drop and improving the quality of the jet organization.

[0037] Regarding the channel adjustment structure, a movable slider is installed between the two jet channels. The length change of the movable slider is used to adjust the jet orifice opening size and the distance between the two jet orifices, thereby changing the dimensionless parameters and controlling the flow output. In addition, the jet flow distribution between the two channels can be adjusted by the slider position offset, enabling the device to offset the jet flow in the hot spot areas on the left or right, thereby obtaining a more balanced heat exchange effect under the condition of local hot spot asymmetry.

[0038] In terms of the excitation components, the vibrating diaphragm is made of piezoelectric ceramic material, which can generate a reverse piezoelectric effect and stable periodic vibration under the action of periodic voltage, realizing the conversion of electrical energy into the mechanical vibration kinetic energy of the thin film, and providing a driving source for the subsequent formation of periodic volume oscillation.

[0039] In terms of cavity matching, the exciter cavity is designed with a smooth inner wall structure, and the cavity volume is matched with the vibration stroke of the diaphragm to ensure that the fluid in the cavity forms a sufficient volume change range during the reciprocating motion of the diaphragm, thereby improving the excitation reliability of the jet self-sufficiency effect and the formation quality of the vortex structure.

[0040] In terms of structural dimensions, the diameter of the local hot spot in the electronic component is 0.5 mm. The specific dimensions of the piezoelectric synthesized dual-jet device in this embodiment include: an actuator solid structure size of 10 mm × 1 mm, an actuator cavity size of 8 mm × 2 mm, a jet outlet width of 0.5 mm, a distance of 2 mm between the two jet holes, a diaphragm diameter of 8 mm, and a thickness of 0.2 mm. These structural dimensions meet the spatial integration requirements for local hot spot cooling and are compatible with the electronic component layout environment.

[0041] Regarding the verification of dimensionless parameters, the dimensionless parameter S was calculated under the above structural parameter configuration. tk The value is 550.24, which is greater than the S required to form the self-sufficiency effect of the synthetic dual jet. tk With a threshold of >420, the self-sufficiency condition is met, thus enabling the formation of a strong vortex structure covering 360° in a local area of ​​the electronic component and achieving high-frequency disturbance heat transfer.

[0042] like Figure 3 As shown, this embodiment employs a piezoelectric synthetic dual-jet exciter to achieve high-frequency perturbation heat transfer targeting localized hot spots in electronic components. The device includes a vibrating membrane for forming periodic volumetric oscillations, an exciter cavity and exciter solid structure for defining the space for volumetric changes, dual jet orifices positioned directly opposite the vibrating membrane and facing the localized hot spots of the electronic component, and a movable slider located between the dual jet orifices. The movable slider is used to adjust the opening size of the dual jet orifices and the distance between the two jet orifices, thereby changing the jet distribution and dimensionless parameters to adapt to different hot spot locations and cooling requirements. The localized hot spots of the electronic component are arranged downstream of the jet direction of the dual jet orifices so that the resulting high-frequency oscillating jets directly act on the temperature concentration area, achieving locally enhanced convective heat transfer.

[0043] In a performance verification of one implementation, under an input velocity of 1 m / s, the piezoelectric synthetic dual-jet device was able to accelerate the fluid to approximately 15–20 m / s at the jet outlet. Simultaneously, a high-speed vortex structure of approximately 5–15 m / s was formed in the flow region where the local hotspot of the electronic component was located. This high-speed vortex continuously swept across the hotspot surface, rapidly disrupting and re-establishing the temperature boundary layer, significantly reducing boundary layer thermal resistance, thereby significantly enhancing the local convective heat transfer coefficient and achieving a strengthened cooling effect on the local high-temperature region.

[0044] The convective heat transfer performance under different combinations of input velocity and driving frequency was further quantified through numerical calculation and experimental testing. As shown in Table 1, when the input velocity is 1 m / s, the convective heat transfer coefficient is approximately 265.59 W / (m²) at driving frequencies of 300 Hz, 500 Hz, 700 Hz, and 900 Hz. 2 ·K), 306.06W / (m 2 ·K), 320.63W / (m 2 ·K) and 355.20W / (m 2 The convective heat transfer coefficient (·K) increases monotonically with increasing frequency; when the input velocity is increased to 1.2 m / s and 1.5 m / s, under the same frequency conditions, the convective heat transfer coefficient further increases, reaching a maximum of approximately 364.05 W / (m³). 2 The result (·K) indicates that under the self-sufficiency effect of the synthetic dual jet, the superposition of high-frequency oscillation and higher inlet velocity can generate stronger eddy current disturbance and higher heat transfer capacity.

[0045] Regarding operating condition adaptability and material reliability, this embodiment demonstrates that, at a constant input speed, a higher driving frequency results in better heat exchange. However, the input speed and driving frequency are also limited by factors such as the strength, fatigue life, and driving capability of the vibrating diaphragm material. Excessive flow rate or frequency can adversely affect the usability limits of the vibrating diaphragm material. Therefore, within the acceptable operating range of the vibrating diaphragm material, appropriately increasing the input frequency and speed can significantly improve the heat exchange effect without exceeding the material's safety margin, achieving an optimal trade-off between enhanced heat exchange performance and structural reliability.

[0046] Table 1 Convection heat transfer performance

[0047] In one implementation, such as Figure 4 As shown, the numerical calculation results of the synthetic dual-jet self-sufficiency effect are presented in the form of velocity contour maps. The horizontal color bars indicate the scale range of the flow field velocity, with different color levels corresponding to the low-velocity region near zero to the high-velocity region of about 13 m / s. This is used to quantitatively distinguish the velocity magnitudes of the jet outlet, the vortex region near the hot spot, and the far-field mainstream region, providing a velocity scale basis for analyzing the subsequent formation process of the self-sufficiency phenomenon and the vortex heat transfer mechanism.

[0048] like Figure 5As shown, in the initial stage of the self-sufficiency phenomenon, the two jets begin to emerge from the two jet holes under the periodic driving force. The jet closer to the local hot spot of the electronic component is deflected and locally accelerated under the induction of the suction flow on the opposite side, forming an unclosed rotating flow structure above the hot spot. This stage indicates that a feedback channel has been established between the jet outlet and the oscillating flow inside the cavity, and the prototype of the self-sufficient jet has begun to appear, but the annular vortex structure has not yet completely covered the hot spot area.

[0049] like Figure 6 As shown, the self-contained jet further develops, forming a large-scale annular vortex that is essentially closed around the local hot spot of the electronic component. The high-speed jet is entrained along the circumference of the hot spot and flows back to the cavity inlet region. A distinct high-velocity zone and strong shear zone are present near the hot spot. During this stage, the self-contained vortex continuously scours and sweeps the surface of the hot spot, causing the temperature boundary layer to be repeatedly destroyed and rebuilt. Local convective heat transfer is significantly enhanced, demonstrating the dominant role of the self-contained vortex in the heat transfer of the hot spot.

[0050] like Figure 7 As shown, the self-contained jet enters the heat transfer stage where it merges with the external flow field. The annular vortex interacts with the upstream mainstream and the surrounding background flow, and the vortex core position and vortex distribution expand in the vertical direction. The high-speed jet mixes with the external flow field to form a larger-scale disturbance region. In this stage, the self-contained jet not only enhances local heat transfer near the hot spot, but also, through merging with the external flow field, transports the high-momentum fluid to a wider range, improving the overall heat transfer uniformity.

[0051] like Figure 8 As shown, the synthetic dual jets reach the stage of self-sufficient formation in the opposite direction. After completing one development cycle, the annular vortex is re-established in the opposite direction, and the jet deflection direction is reversed compared to the previous cycle. A local high-speed region forms on the other side of the hot spot. This stage characterizes the self-sufficient jet achieving a self-sustaining cycle of alternating directions within one oscillation cycle. The high-speed vortex sweeps across the hot spot region from different directions in sequence, increasing the frequency and coverage of flow disturbances in the time dimension, thereby further enhancing the local high-frequency heat transfer effect.

[0052] The beneficial effects of this invention are as follows: (1) It has outstanding high-frequency operation characteristics. The actual working frequency is twice the input frequency. Through the high-frequency response characteristics of the exciter, it can achieve a wide range of high-frequency operation from 200HZ to 1000HZ. The working fluid has a high flow frequency, which can quickly remove the heat from the hot spot area of ​​the electronic components and avoid heat accumulation. (2) Small input can generate high speed: When the input speed of the vibrating diaphragm is 1 m / s under typical working conditions, a high-speed eddy current of 10-20 m / s can be generated in the flow region. The high-speed eddy current flow causes the temperature boundary layer at the hot spot to be destroyed rapidly, which enhances its heat transfer coefficient. (3) Significantly improved heat exchange efficiency: Under self-sufficient working conditions, the local convective heat transfer coefficient is significantly improved compared with the traditional steady-state air cooling. At different frequencies such as 300Hz and 500Hz, the convective heat transfer coefficient near the edge of the element and the hot spot can be increased from tens to hundreds, realizing rapid, stable cooling and heat exchange under high heat flux density. (4) Enhanced heat transfer by synthesizing a dual-jet unit: The solid region of the exciter increases the heat transfer area around the electronic components, which has the effect of finned heat transfer enhancement. While serving as a dual-jet exciter, it is also equivalent to adding fins to the electronic components, thereby increasing their overall heat transfer effect; (5) High adaptability and controllable energy consumption: The input voltage amplitude and frequency can be dynamically adjusted to adapt to electronic components with different power and heat generation; at the same time, when the component generates low heat, the frequency and amplitude can be reduced, which can effectively reduce the energy consumption of the device and meet the energy-saving requirements.

[0053] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0054] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for enhancing heat transfer by utilizing the self-sufficiency effect of synthetic dual jets to achieve high-frequency disturbances, characterized in that, include: The location and characteristic length of local high-temperature hot spots in electronic components are determined by simulation verification or temperature measurement, and the hot spot region is determined based on the location and characteristic length of the local high-temperature hot spots; A pair of jet channels facing the hot spot are arranged in the hot spot area. A vibrating element is arranged between the two jet channels, with the vibration direction of the vibrating element perpendicular to the jet spray direction. A solid is arranged to connect the jet channels and the vibrating element, so that the solid forms two cavities, left and right. Only the two jet channels in the left and right cavities exchange mass and energy with the outside world, so that the working fluid exchanges back and forth between the left and right cavities and the external flow field through the two jet channels. The vibrating element located upstream of the two jet channels is driven to vibrate periodically at a preset input frequency using a periodic driving method, causing the fluid in the left and right cavities to oscillate in volume, forming two jet nozzles at the outlets of the two jet channels, and forming an oscillating jet at the two jet nozzles with the same preset input frequency; the actual vibration frequency after the two oscillating jets are coupled is twice the preset input frequency; The spacing between the two jet channels, the width of the jet channels, and the vibration element are adjusted according to the formation criteria of the synthetic dual-jet self-sufficiency phenomenon, and dimensionless parameters are calculated based on the parameters of each element. When the dimensionless parameter does not meet the formation criterion, the diameter of the vibrating element is increased, the width of the jet channel is decreased, and the distance between the two jet channels is decreased, so that the dimensionless parameter is controlled within the self-sufficiency range, thereby generating a strong vortex region covering 360° around the hot spot by the oscillating jet.

2. The enhanced heat transfer method for high-frequency disturbances using the self-sufficiency effect of synthetic dual jets according to claim 1, characterized in that, Based on the formation criteria of the synthetic dual-jet self-sufficiency phenomenon, the spacing between the two jet channels, the width of the jet channels, and the vibration element are adjusted, and dimensionless parameters are calculated based on the parameters of each element, including: The dimensionless parameter is defined as S. tk ; The S is calculated based on the spacing between the two jet channels, the width of the jet channels, the structural parameters of the vibrating element, and the preset input frequency. tk .

3. The enhanced heat transfer method for high-frequency disturbances using the self-sufficiency effect of synthetic dual jets according to claim 2, characterized in that, The method further includes adjusting the spacing between the two jet channels, the width of the jet channels, and the vibration element according to the formation criteria of the synthetic dual-jet self-sufficiency phenomenon, and calculating dimensionless parameters based on the parameters of each element. The formation criterion is limited to the S. tk Greater than 420; The self-sufficiency range is limited to S. tk Greater than 420.

4. The enhanced heat transfer method for high-frequency disturbances using the self-sufficiency effect of synthetic dual jets according to claim 1, characterized in that, When the dimensionless parameter does not meet the formation criterion, increasing the diameter of the vibrating element, decreasing the width of the jet channel, and decreasing the distance between the two jet channels includes: While keeping the preset input frequency constant, first reduce the width of the jet channel; The diameter of the vibrating element is increased after the width of the jet channel is reduced; After the diameter of the vibrating element is increased, the distance between the two jet channels is reduced so that the dimensionless parameter satisfies the formation criterion.

5. The enhanced heat transfer method for high-frequency disturbances using the self-sufficiency effect of synthetic dual jets according to claim 1, characterized in that, The vibration element located upstream of the two jet channels is driven to vibrate periodically at a preset input frequency using a periodic driving method, including: A periodic drive signal is applied to the vibrating element; The frequency of the periodic drive signal is made to match the preset input frequency, so as to drive the vibration element to generate the periodic vibration.

6. The enhanced heat transfer method for high-frequency disturbances using the self-sufficiency effect of synthetic dual jets according to claim 5, characterized in that, Applying a periodic drive signal to the vibrating element includes: The periodic drive signal is set to a periodically changing voltage signal; The periodic vibration is generated by driving the vibrating element through the periodically changing voltage signal.

7. The enhanced heat transfer method for high-frequency disturbances using the self-sufficiency effect of synthetic dual jets according to claim 1, characterized in that, The vibrating element is a piezoelectric diaphragm; the piezoelectric diaphragm vibrates periodically at the preset input frequency to cause the fluid in the left and right cavities to generate the volumetric oscillation.

8. The enhanced heat transfer method for high-frequency disturbances using the self-sufficiency effect of synthetic dual jets according to claim 1, characterized in that, The inner walls of the left and right cavities are smooth; the volume of the left and right cavities is adapted to the vibration stroke of the vibrating element to form the volume oscillation.

9. The enhanced heat transfer method for high-frequency disturbances using the self-sufficiency effect of synthetic dual jets according to claim 1, characterized in that, The vibration element located upstream of the two jet channels is driven to vibrate periodically at a preset input frequency using a periodic driving method, including: The preset input frequency is limited to 300Hz to 900Hz; Under the condition that the preset input frequency is 300Hz to 900Hz, the actual vibration frequency after the two oscillating jets are coupled is twice the preset input frequency.

10. The enhanced heat transfer method for high-frequency disturbances using the self-sufficiency effect of synthetic dual jets according to claim 7, characterized in that, The process of achieving the actual vibration frequency being twice the preset input frequency after coupling of the two oscillating jets includes: When the vibrating element vibrates periodically at the preset input frequency, the fluid velocity on both sides of the vibrating element has an opposite phase difference, so that the fluid in the left and right cavities is in the state of discharge and intake at the same time. Under the action of the discharge and intake states, the fluid velocity directions at the two jet nozzles are reversed, and the pressures in the left and right chambers are reversed; When the distance between the two jet channels satisfies the jet interaction condition, the fluid on the discharge side is deflected and accelerated under the influence of the fluid on the suction side, and is further drawn into the cavity of the suction range, thereby forming a stable periodic self-sufficient flow that can be maintained without jet replenishment, so as to realize the coupling of the two oscillating jets and make the actual vibration frequency of the entire device twice the preset input frequency.

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