Electric field reinforced anti-disturbance heat dissipation channel structure and method for ship electronic equipment

Abstract

This invention provides an electric field-enhanced heat dissipation channel structure and method for marine electronic equipment, belonging to the field of power equipment thermal management technology. The structure includes an IGBT module unit, a U-shaped microchannel heat dissipation unit, an EHD drive unit, a working fluid compensation unit, and an electronic control unit. The U-shaped microchannel is located within a high thermal conductivity heat dissipation substrate and is formed by alternating series connection of rectangular cross-section straight sections, transition sections, and circular cross-section sections, filled with a shear-thinned non-Newtonian dielectric fluid. The EHD drive unit includes plate-to-plate electrode pairs and coaxial ring electrode pairs arranged alternately along the U-shaped microchannel, powered by the same high-voltage DC power supply and decoupled by an electrodeless transition section. The electronic control unit adjusts the electric field parameters according to junction temperature, vibration, tilt angle, and temperature. The working fluid compensation unit maintains the closed-loop pressure and fill level for heat dissipation of marine IGBTs. This invention improves the heat dissipation stability of marine IGBTs under complex dynamic operating conditions.

Description

Technical Field

[0001] This invention belongs to the field of thermal management technology for power equipment, and particularly relates to a structure and method for an electric field-enhanced heat dissipation channel for marine electronic equipment to resist disturbances. Background Technology

[0002] High-power IGBT modules in marine electric propulsion systems generate high heat flux density during energy conversion, and their junction temperature variations affect switching characteristics, fatigue life, and system reliability. Furthermore, the ship's engine room experiences wide-frequency vibrations, roll and pitch, temperature variations, and limited installation space, placing demands on the disturbance resistance and long-term stability of the heat dissipation structure.

[0003] Existing mechanical pump liquid cooling, heat pipe, or conventional microchannel heat dissipation methods typically rely on mechanical drives or fixed flow channel structures. These methods may encounter problems such as uneven flow distribution, localized bubbles, pipe fatigue, or high auxiliary power consumption in ship vibration and tilting environments. Electrohydrodynamic (EHD) technology can generate volume forces in dielectric liquids through an electric field, thereby driving fluid flow and enhancing heat transfer; however, combining charge-injected EHD drive, shear-thinned non-Newtonian dielectric liquids, and loop-shaped microchannel structures adapted for marine IGBTs for heat dissipation under dynamic and complex ship operating conditions still requires further structural design. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a disturbance-resistant and stable microchannel structure and method for enhancing the heat dissipation of marine power electronic equipment by electric field enhancement, so as to improve the heat dissipation stability of marine IGBT modules under vibration, tilt and wide temperature range conditions.

[0005] The first aspect of this invention proposes an electric field-enhanced anti-disturbance heat dissipation channel structure for marine electronic equipment, including an IGBT module unit, a U-shaped microchannel heat dissipation unit, an EHD drive unit, a working fluid compensation unit, and an electronic control unit; The IGBT module unit includes an IGBT module for a marine electric propulsion frequency converter, a high thermal conductivity heat dissipation substrate, and a junction temperature monitoring module. The heating surface of the IGBT module is attached to the upper surface of the high thermal conductivity heat dissipation substrate, and the junction temperature monitoring module is communicatively connected to the electronic control unit. The U-shaped microchannel heat dissipation unit includes a U-shaped microchannel encapsulated in the high thermal conductivity heat dissipation substrate and located below the heating surface of the IGBT module. The U-shaped microchannel is formed by alternating and connecting rectangular cross-section straight segments, transition segments and circular cross-section segments to form a multi-segment U-shaped continuous U-shaped structure. The U-shaped microchannel is filled with a non-Newtonian dielectric liquid with shear thinning properties. The EHD drive unit includes multiple sets of charge-injection electrode pairs, high-voltage insulated leads, and a high-voltage DC power supply. The multiple sets of charge-injection electrode pairs are formed by alternating plate-to-plate electrode pairs and coaxial ring electrode pairs along the loop-shaped microchannel. The plate-to-plate electrode pairs are arranged on the rectangular cross-section straight section, and the coaxial ring electrode pairs are arranged on the circular cross-section section. The transition section is an electrode-free section. Both the plate-to-plate electrode pairs and the coaxial ring electrode pairs are connected to the high-voltage DC power supply through the high-voltage insulated leads. The control terminal of the high-voltage DC power supply is communicatively connected to the electronic control unit. The working fluid compensation unit is connected to the loop-shaped microchannel to form a closed loop for the circulation of the non-Newtonian dielectric liquid. The closed loop is provided with a heat dissipation surface that is thermally coupled to the high thermal conductivity heat dissipation substrate, the outer wall of the closed liquid storage tank and / or the ship cooling structure, for releasing the heat carried out by the non-Newtonian dielectric liquid to the outside.

[0006] Preferably, the rectangular section of the U-shaped microchannel extends parallel to the underside of the IGBT module's heating surface and conforms to the rectangular projection area of ​​the IGBT module's heating surface to form the main heat dissipation area. The circular section is located at the U-shaped bend and / or axisymmetric confluence section of the U-shaped microchannel. The transition section is a smoothly transitional section with a gradually changing cross-section, and its length is 3 to 5 times the equivalent diameter of the flow channel. The two ends of the transition section are continuously connected to the rectangular section and the circular section, respectively. The inner wall of the U-shaped microchannel is provided with continuously distributed micro-scale ribs, and the extension direction of the micro-scale ribs is consistent with the mainstream fluid direction. The coverage area of ​​the U-shaped microchannel matches the heating surface area of ​​the IGBT module.

[0007] Preferably, the emitter and collector of the plate-plate electrode pair are both plate-shaped electrodes, arranged parallel to the upper and lower inner walls or the inner walls on both sides of the straight section of the rectangular cross-section, with the plate surface parallel to the mainstream fluid direction; the emitter and collector have a preset misalignment, segmented polarity configuration or segmented power supply configuration in the flow direction, so that the electric field lines and space charge density are asymmetrically distributed along the flow direction, thereby forming a Coulomb volume force component along the mainstream fluid direction in the non-Newtonian dielectric liquid, so as to induce a flow that tends to be a plunger flow distribution in the straight section of the rectangular cross-section and enhance the heat transfer of the near-wall thermal boundary layer.

[0008] Preferably, the emitting electrode of the coaxial annular electrode pair is a central columnar electrode arranged along the axis of the circular cross-section segment, and the collecting electrode is an annular electrode arranged coaxially with the circular cross-section segment. The central columnar electrode is positioned on the central axis of the circular cross-section segment by an insulating support, and the annular electrode is attached and fixed to the inner wall of the circular cross-section segment. The central columnar electrode and / or the annular electrode are segmented along the axial direction of the circular cross-section segment, and there is an axial potential difference or polarity bias between adjacent electrode segments, so that a radial electric field and a space charge distribution that varies along the axial direction are formed in the circular cross-section segment, thereby generating a Coulomb volume force with an axial component to induce the formation of an axisymmetric swirling or circulating field.

[0009] Preferably, the plate-plate electrode pairs and the coaxial annular electrode pairs are arranged alternately along the flow direction of the loop-shaped microchannel and are uniformly connected to the high-voltage DC power supply through multiple branch high-voltage insulated leads; the high-voltage DC power supply has at least two independently adjustable high-voltage output channels, which provide working voltages for the plate-plate electrode pairs and the coaxial annular electrode pairs respectively and are independently adjusted by the electronic control unit; the plate-plate electrode pairs form volume forces with flow components in the straight section of the rectangular cross-section by flow direction misalignment, segmented power supply, or polarity bias, and the coaxial annular electrode pairs form volume forces with axial components in the circular cross-section by axial segmentation or polarity bias; the transition section is an electrode-free section that spatially decouples the electric fields formed by the two types of electrodes.

[0010] Preferably, the non-Newtonian dielectric liquid is a cationic polyacrylamide-modified electronic fluorinated liquid or transformer oil, and is a shear-thinning viscoelastic non-Newtonian fluid with a volume ratio of: 95-98 parts of basic dielectric liquid, 1-4 parts of cationic polyacrylamide, and 0.5-1 parts of hydrophobic nano-silica particles.

[0011] Preferably, the working fluid compensation unit includes a closed-loop liquid storage tank, a pressure compensator, and connecting pipelines. The closed-loop liquid storage tank is connected to the inlet and outlet ends of the loop-shaped microchannel via the connecting pipelines. The pressure compensator is connected to the closed-loop liquid storage tank. An insulated sealing joint is provided on the connecting pipelines. The outer wall of the closed-loop liquid storage tank and / or the lower surface of the high thermal conductivity heat dissipation substrate form a heat dissipation surface that is thermally coupled with the ship mounting base, cold plate, or shell.

[0012] Preferably, the electrical control unit includes a PLC controller, a signal acquisition module, and a drive module. The signal acquisition module is communicatively connected to the junction temperature monitoring module, vibration sensor, tilt sensor, and ambient temperature sensor. The drive module is connected to the control terminal of the high-voltage DC power supply to adjust the electric field parameters according to the IGBT junction temperature, ship vibration, tilting conditions, and ambient temperature.

[0013] Preferably, the high-voltage DC power supply is equipped with a current limiting protection module, an overvoltage protection module, and a shutdown discharge module. The high-voltage insulated leads of the plate-to-plate electrode pair and the coaxial ring electrode pair are double-insulated and led out through an insulating through-barrier structure. The high-voltage DC power supply and its casing are grounded and shielded. The working fluid compensation unit, in conjunction with the vacuum degassing process, improves the full-fill retention capability of the non-Newtonian dielectric liquid in the loop-shaped microchannel, thereby reducing the risk of partial discharge and insulation breakdown caused by bubbles.

[0014] The second aspect of this invention provides an electric field-enhanced method for heat dissipation in marine electronic equipment to resist disturbances. Employing the heat dissipation channel structure described in the first aspect, the method includes the following steps: injecting the non-Newtonian dielectric liquid into a loop-shaped microchannel through a working fluid compensation unit and removing air bubbles; acquiring the IGBT junction temperature through a junction temperature monitoring module and transmitting it to the electronic control unit; applying a high-voltage DC electric field to the plate-plate electrode pair and the coaxial annular electrode pair respectively through a high-voltage DC power supply, causing space charges to form in the non-Newtonian dielectric liquid and, under the action of Coulomb volume forces, forming a tendency towards plunger flow in the straight section of the rectangular cross-section. The fabric flows in a directional manner, forming an axisymmetric swirling or circulating flow in the circular cross-section, and circulates directionally along the loop-shaped microchannel; the non-Newtonian dielectric liquid absorbs and carries away the heat conducted from the IGBT module to the high thermal conductivity heat dissipation substrate, and the heat is released outward through the high thermal conductivity heat dissipation substrate, the outer wall of the closed liquid storage tank, and / or the heat dissipation surface coupled with the ship's cooling structure; the electric control unit independently adjusts the electric field parameters of the plate-to-plate electrode pair and the coaxial annular electrode pair according to the IGBT junction temperature and the ship's engine room operating conditions, and the working fluid compensation unit compensates for the pressure fluctuations in the closed loop.

[0015] Preferably, the working electric field strength of the plate-plate electrode pair and the coaxial ring electrode pair is 1 to 5 kV / mm, the flow Reynolds number of the non-Newtonian dielectric liquid driven by Coulomb volume force is 50 to 500, and the junction temperature closed-loop control response time of the electronic control unit is preferably no more than 10 ms.

[0016] Preferably, when the IGBT heat flux density is 50-150 W / cm², the electric field strength is controlled at 1-3 kV / mm; when the IGBT heat flux density is 150-300 W / cm², the electric field strength is controlled at 3-5 kV / mm; when the ambient temperature is below 0℃, the electric field strength is increased by 0.5-1 kV / mm based on the corresponding heat flux density operating condition.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention reduces reliance on mechanical moving parts through charge-injected EHD drive; reduces flow resistance and enhances near-wall heat transfer through shear-thinned non-Newtonian dielectric fluid; and through a combination design of plate-plate electrode pairs and coaxial annular electrode pairs arranged alternately along a loop-shaped microchannel, it forms a directional flow tending towards plunger flow distribution in the straight section of the rectangular cross-section, and an axisymmetric swirling or circulating flow in the circular cross-section, which is spatially decoupled and continuously connected through an electrodeless transition section, thereby suppressing the influence of ship vibration, tilting, and temperature changes on the flow field and heat transfer uniformity. Combined with the working fluid compensation unit and the electronic control unit, it can improve the heat dissipation stability of marine IGBTs under complex dynamic conditions.

[0018] Simulation experiments provide a feasibility study for the disturbance-resistant and stable microchannel structure described in this invention, considering heat transfer gain, flow stability, and adaptability to operating conditions. This structure enables active heat dissipation with adjustable electric field without mechanical moving parts, making it suitable for the thermal management needs of marine power electronic equipment in confined spaces, under high heat flux density, and disturbance conditions. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the following description is only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure of the disturbance-resistant and stable microchannel structure of the present invention.

[0021] Figure 2 This is a schematic diagram of the arrangement structure of the charge-injection electrode pair in the loop-shaped microchannel of the present invention.

[0022] Figure 3 This is a schematic diagram of the plate-plate electrode pair of the present invention.

[0023] Figure 4 This is a schematic diagram of the coaxial ring electrode pair of the present invention.

[0024] Figure 5 This is a schematic diagram of the enhanced heat dissipation method for marine IGBT EHD according to the present invention.

[0025] Figure 6 For this invention, Ra=10 3 Transient variation of the Nusselt number over time under multiple electric field intensities under the operating conditions; where (a) is the evolution of the Nusselt number over time (dimensionless processing is performed using the reference Nusselt number (Nu0) under the no-electric-field condition); (b) is the curve of fluid kinetic energy change over time.

[0026] Figure 7 This is a diagram illustrating the heat transfer enhancement under the influence of an electric field in an embodiment of the present invention; where (a) represents the Coulomb force F of the electric field. i The average Nusselt number is in the same direction as gravity and downwards. (b) is the relationship between the electric field and the Coulomb force F. i The average Nusselt number is the one that moves in the opposite direction to gravity. The relationship; (c) is the Coulomb force F in the electric field. i Enhancement ratio in the same direction as gravity and The relationship; (d) is the Coulomb force F in the electric field. i Enhancement ratio in the opposite direction of gravity and The relationship.

[0027] Figure 8 Temperature contour maps and isotherm distribution maps for different inlet velocities; (a) Uavg = 0.001 m / s; (b) Uavg = 0.005 m / s; (c) Uavg = 0.01 m / s.

[0028] Explanation of reference numerals in the attached diagram: 1. IGBT module; 2. High thermal conductivity heat dissipation substrate; 3. Junction temperature monitoring module; 4. Electronic control unit; 5. U-shaped microchannel; 6. Non-Newtonian dielectric liquid; 7. Charge injection electrode pair; 8. High voltage DC power supply; 9. Closed liquid storage tank; 10. Pressure compensator; 71. Emitter; 72. Collector. Detailed Implementation

[0029] The present invention will be further described below with reference to embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0030] like Figure 1 As shown, the disturbance-resistant stable microchannel structure of this embodiment includes an IGBT module 1, a high thermal conductivity heat dissipation substrate 2, a junction temperature monitoring module 3, an electronic control unit 4, a loop-shaped microchannel 5, a non-Newtonian dielectric liquid 6, a charge injection electrode pair 7, a high-voltage DC power supply 8, a closed-loop liquid reservoir 9, and a pressure compensator 10. The heating surface of the IGBT module 1 is attached to the high thermal conductivity heat dissipation substrate 2. The junction temperature monitoring module 3 is used to collect the junction temperature signal of the IGBT module 1. The loop-shaped microchannel 5 is disposed within the high thermal conductivity heat dissipation substrate 2 and located below the heating surface of the IGBT module 1.

[0031] The U-shaped microchannel 5 is a multi-segment continuous U-shaped structure formed by alternating rectangular cross-section straight sections, transition sections, and circular cross-section sections. Microscale ribs extending along the mainstream direction are set on the inner wall of the flow channel. The rectangular cross-section straight sections extend parallel to the heating surface of the IGBT module 1 and conform to the rectangular projection area of ​​the heating surface of the IGBT module to form the main heat dissipation area; the circular cross-section sections are set at the U-shaped bends and / or axisymmetric confluence sections of the U-shaped microchannel 5; the transition section is a smoothly transitioned section with a gradually changing cross-section and a length of 3 to 5 times the equivalent diameter of the flow channel, and its two ends are continuously connected to the rectangular cross-section straight sections and the circular cross-section sections, respectively.

[0032] Non-Newtonian dielectric fluid 6 can be an electronic fluorinated fluid or transformer oil modified with cationic polyacrylamide, and is a shear-thinning viscoelastic non-Newtonian fluid. Its volume ratio can be 95-98 parts of the base dielectric fluid, 1-4 parts of cationic polyacrylamide, and 0.5-1 parts of hydrophobic nano-silica particles.

[0033] like Figure 2 As shown, the charge-injection electrode pairs 7 are arranged alternately along the rectangular and circular cross-sections of the loop-shaped microchannel 5 to form a continuous, directional Coulomb volume force within the loop-shaped microchannel 5. Each charge-injection electrode pair 7 includes an emitter 71 and a collector 72, which are connected to a high-voltage DC power supply 8 via multi-branched high-voltage insulated leads.

[0034] like Figure 3 and Figure 4 As shown, the charge-injection electrode pair 7 of this embodiment is formed by combining a plate-plate electrode pair and a coaxial annular electrode pair. In the plate-plate electrode pair, the emitter 71 and the collector 72 are both plate-shaped electrodes, and are arranged in parallel on the upper and lower inner walls or the inner walls on both sides of the straight section of the rectangular cross-section. The plate surfaces are parallel to the mainstream direction of the fluid. The emitter 71 and the collector 72 can have a preset misalignment of 0.2 to 2 times the plate spacing in the flow direction, or be segmented along the flow direction to be configured with alternating polarities, so that the electric field lines and space charge density are asymmetrically distributed along the flow direction, thereby forming a Coulomb volume force component along the mainstream direction of the fluid.

[0035] In the coaxial ring electrode pair, the emitter 71 is a central columnar electrode arranged along the axis of the circular cross-section segment, and the collector 72 is a ring electrode arranged coaxially with the circular cross-section segment. The central columnar electrode is positioned on the central axis of the circular cross-section segment by an insulating support, and the ring electrode is attached and fixed to the inner wall of the circular cross-section segment. The central columnar electrode and / or the ring electrode can be segmented along the axial direction of the circular cross-section segment, and an axial potential difference or polarity bias is set between adjacent electrode segments to couple the radial electric field with the space charge distribution that varies along the axial direction, thereby forming a Coulomb volume force with an axial component.

[0036] In the loop-shaped microchannel 5, plate-plate electrode pairs are arranged in the straight section of the rectangular cross-section to form a directional flow tending towards a plunger flow distribution. Coaxial annular electrode pairs are arranged in the circular cross-section to form an axisymmetric swirling or circulating flow. The transition section is an electrode-free section. This configuration spatially decouples the electric fields formed by the two types of electrodes and achieves continuous connection between the rectangular and circular cross-sections. This combined configuration can reduce the risk of near-wall flow stagnation caused by broadband vibrations and localized flow deviation caused by roll and pitch. Furthermore, the electronic control unit 4 performs segmented adjustments according to operating conditions to improve flow field stability and heat transfer uniformity.

[0037] In the plate-plate electrode alignment, the emitter 71 and collector 72 can be made of 316L stainless steel flat plates, fixed to the upper and lower inner walls or the inner walls of the rectangular cross-section section by ceramic insulating pads. In the coaxial ring electrode alignment, the central columnar electrode can be a tungsten alloy electrode, and the ring electrode can be a 316L stainless steel electrode. The central columnar electrode is positioned on the central axis of the circular cross-section section by a polytetrafluoroethylene insulating bracket, and the ring electrode is fitted and fixed to the inner wall of the circular cross-section section.

[0038] The closed-loop storage tank 9 is connected to the inlet and outlet ends of the loop-shaped microchannel 5 via connecting pipes, and the pressure compensator 10 is connected to the closed-loop storage tank 9. Insulated sealing joints can be installed on the connecting pipes, and the pressure compensator 10 can be a bellows-type constant pressure compensator to compensate for volume changes and pressure fluctuations caused by changes in ambient temperature and working fluid temperature. The non-Newtonian dielectric liquid 6 absorbs heat from the IGBT module 1 conducted to the high thermal conductivity heat dissipation substrate 2 within the loop-shaped microchannel 5, and then flows back to the loop-shaped microchannel 5 via the closed-loop storage tank 9 and connecting pipes. Heat can be released outwards through the lower surface of the high thermal conductivity heat dissipation substrate 2, the outer wall of the closed-loop storage tank 9, and / or the heat dissipation surface thermally coupled with the ship's cold plate, mounting base, or engine room shell.

[0039] The electrical control unit 4 may include a PLC controller, a signal acquisition module, and a drive module. The signal acquisition module is communicatively connected to the junction temperature monitoring module 3, the vibration sensor, the tilt sensor, and the ambient temperature sensor. The drive module is connected to the control terminal of the high-voltage DC power supply 8. The electrical control unit 4 can adjust the output voltage and electrode pair operating status of the high-voltage DC power supply 8 according to the IGBT junction temperature, ship vibration, tilting conditions, and ambient temperature.

[0040] like Figure 5As shown, the enhanced heat dissipation method for marine IGBT EHD in this embodiment includes steps S1 to S5. S1: A non-Newtonian dielectric liquid 6 is injected into the loop-shaped microchannel 5 through the working fluid compensation unit, and air bubbles are removed; S2: The junction temperature of the IGBT is collected by the junction temperature monitoring module 3 and transmitted to the electronic control unit 4; S3: A high-voltage DC power supply 8 applies a DC high-voltage electric field to the plate-to-plate electrode pair and the coaxial ring electrode pair respectively, causing space charges to form in the non-Newtonian dielectric liquid 6, which then circulate directionally along the loop-shaped microchannel 5 under the action of Coulomb volume force; S4: The flowing non-Newtonian dielectric liquid 6 absorbs the heat conducted from the IGBT module 1 to the high thermal conductivity heat dissipation substrate 2 and releases it outward through the heat dissipation surface; S5: The electronic control unit 4 independently adjusts the electric field parameters of the two types of electrode pairs according to the junction temperature and the ship's engine room operating conditions, and the working fluid compensation unit compensates for pressure fluctuations in the closed loop.

[0041] In one embodiment, the operating electric field strength of both the plate-to-plate electrode pair and the coaxial ring electrode pair is 1–5 kV / mm, and the Reynolds number of the non-Newtonian dielectric liquid 6 driven by Coulomb volume force is 50–500. When the heat flux density of the IGBT is 50–150 W / cm², the electric field strength can be controlled between 1–3 kV / mm; when the heat flux density of the IGBT is 150–300 W / cm², the electric field strength can be controlled between 3–5 kV / mm; when the ambient temperature is below 0°C, the electric field strength can be increased by 0.5–1 kV / mm based on the corresponding heat flux density operating condition. The high-voltage DC power supply preferably adopts an integrated protection design of current limiting, overvoltage, and shutdown discharge, and is equipped with at least two independently adjustable high-voltage output channels to supply power to the plate-to-plate electrode pair and the coaxial ring electrode pair respectively.

[0042] During the device initialization phase, vacuum degassing and pressure compensation can improve the full-fill retention capacity of the non-Newtonian dielectric liquid 6 within the flow channel, thereby reducing local electric field distortion, partial discharge, and insulation failure caused by air bubbles. The electrode leads and penetration points can employ a high-voltage resistant insulating potting structure, and the high-voltage DC power supply casing is grounded and shielded. The materials, dimensions, and electric field parameters in the above embodiments can be adjusted according to the IGBT heat flux density, installation space, and ship cooling structure.

[0043] To further verify the feasibility of the electric field-enhanced heat dissipation structure for marine power electronic equipment described in this invention, its heat transfer enhancement mechanism and operational stability can be explained by combining relevant numerical simulation results. Existing EHD numerical simulation results show that, with the increase of the dimensionless parameter characterizing the intensity of the electric field... Increase, local Nusselt number and enhancement ratio The overall trend is upward, indicating that Coulomb volume forces can effectively induce near-wall fluid disturbance, disrupt the thermal boundary layer, and enhance the mixing of hot and cold fluids, thereby improving local heat transfer capacity.

[0044] like Figure 6As shown, under fixed natural convection conditions, the average Nusselt number undergoes a brief adjustment over time before rapidly stabilizing, and with... As the electric field increases, the stability value significantly improves; simultaneously, the system kinetic energy also increases with the enhancement of the electric field and remains stable after the transition phase. This result indicates that the electric field input does not cause persistent flow instability, but rather can be transformed into a stable and controllable flow enhancement effect, demonstrating that the electric field-driven method used in this invention has good operational stability.

[0045] like Figure 7 As shown, within a relatively wide Rayleigh number range, the average Nusselt number and strengthening ratio under different configurations... All follow The overall increase is significant, with some operating conditions showing an almost linear increase, while others show a moderate increase. The results show plateau or saturation characteristics within the range. This indicates that the EHD enhancement effect not only has a significant enhancing trend, but also exhibits adjustability and marginal saturation law, making it suitable for segmented adjustment of the electric field strength through a high-voltage DC power supply and an electronic control unit to adapt to different heat load conditions.

[0046] The influence of inlet velocity on the temperature field and heat transfer performance reveals that while enhanced inlet mainstream velocity increases the flow rate within the channel, it also compresses the EHD-induced recirculation structure and weakens thermal boundary layer disturbances, leading to a decrease in local heat transfer efficiency. This principle, conversely, demonstrates that this invention does not rely solely on increasing mainstream velocity to achieve heat dissipation. Instead, it utilizes the synergistic design of a loop-shaped microchannel, combined electrode pairs, and an electrodeless transition section to provide a stable operating space for EHD volume forces, and achieves locally active enhanced heat transfer through electric field modulation.

[0047] like Figure 8 As shown, under the condition of Uavg = 0.001 m / s, the inlet mainstream is relatively weak, and the EHD-induced vortex structure has the most significant impact on the temperature field. The isotherms exhibit significant deformation near the electrodes, with obvious upward or downward convexity in local areas, indicating strong perturbation of the near-wall thermal boundary layer. The average Nu is highest under this condition, at 1.7906. When the inlet velocity increases to Uavg = 0.005 m / s and Uavg = 0.01 m / s, the curvature of the isotherms gradually weakens, but some local perturbation still exists near the electrodes, and the average Nu decreases to 1.5345 and 1.4240, respectively. These results indicate that under medium-to-low velocity inlet mainstream conditions, EHD-induced backflow can still significantly affect near-wall heat transfer, but its effective range shrinks with increasing mainstream velocity, and the localized enhanced heat transfer effect of EHD weakens with increasing inlet velocity.

[0048] In summary, the numerical simulation results provide a basis for the feasibility of the disturbance-resistant and stable microchannel structure described in this invention, considering heat transfer gain, flow stability, and adaptability to operating conditions. This structure can achieve active heat dissipation with adjustable electric field without mechanical moving parts, making it suitable for the thermal management needs of marine power electronic equipment under confined space, high heat flux density, and disturbed operating conditions.

[0049] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0050] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A disturbance-resistant heat dissipation channel structure for electric field-enhanced marine electronic equipment, characterized in that: It includes IGBT module units, U-shaped microchannel heat dissipation units, EHD drive units, working fluid compensation units, and electronic control units; The IGBT module unit includes an IGBT module for a marine electric propulsion frequency converter, a high thermal conductivity heat dissipation substrate, and a junction temperature monitoring module. The heating surface of the IGBT module is attached to the upper surface of the high thermal conductivity heat dissipation substrate, and the junction temperature monitoring module is communicatively connected to the electronic control unit. The U-shaped microchannel heat dissipation unit includes a U-shaped microchannel encapsulated in the high thermal conductivity heat dissipation substrate and located below the heating surface of the IGBT module. The U-shaped microchannel is formed by alternating and connecting rectangular cross-section straight segments, transition segments and circular cross-section segments to form a multi-segment U-shaped continuous U-shaped structure. The U-shaped microchannel is filled with a non-Newtonian dielectric liquid with shear thinning properties. The EHD drive unit includes multiple sets of charge-injection electrode pairs, high-voltage insulated leads, and a high-voltage DC power supply. The multiple sets of charge-injection electrode pairs are formed by alternating plate-to-plate electrode pairs and coaxial ring electrode pairs along the loop-shaped microchannel. The plate-to-plate electrode pairs are arranged on the rectangular cross-section straight section, and the coaxial ring electrode pairs are arranged on the circular cross-section section. The transition section is an electrode-free section. Both the plate-to-plate electrode pairs and the coaxial ring electrode pairs are connected to the high-voltage DC power supply through the high-voltage insulated leads. The control terminal of the high-voltage DC power supply is communicatively connected to the electronic control unit. The working fluid compensation unit is connected to the loop-shaped microchannel to form a closed loop for the circulation of the non-Newtonian dielectric liquid. The closed loop is provided with a heat dissipation surface that is thermally coupled to the high thermal conductivity heat dissipation substrate, the outer wall of the closed liquid storage tank and / or the ship cooling structure, for releasing the heat carried out by the non-Newtonian dielectric liquid to the outside.

2. The electric field-enhanced anti-disturbance heat dissipation channel structure for marine electronic equipment according to claim 1, characterized in that: The rectangular section of the U-shaped microchannel extends parallel to the underside of the IGBT module's heating surface and conforms to the rectangular projection area of ​​the IGBT module's heating surface to form the main heat dissipation area. The circular section is located at the U-shaped bend and / or axisymmetric confluence section of the U-shaped microchannel. The transition section is a smoothly transitional section with a gradually changing cross-section, and its length is 3 to 5 times the equivalent diameter of the flow channel. The two ends of the transition section are continuously connected to the rectangular section and the circular section, respectively. The inner wall of the U-shaped microchannel is provided with continuously distributed micro-scale ribs, and the extension direction of the micro-scale ribs is consistent with the mainstream fluid direction. The coverage area of ​​the U-shaped microchannel matches the heating surface area of ​​the IGBT module.

3. The electric field-enhanced anti-disturbance heat dissipation channel structure for marine electronic equipment according to claim 1, characterized in that: The emitter and collector of the plate-plate electrode pair are both flat plates, arranged in parallel on the upper and lower inner walls or the inner walls on both sides of the straight section of the rectangular cross-section. The plate surfaces are parallel to the main flow direction of the fluid. The emitter and collector have a pre-set misalignment, segmented polarity configuration, or segmented power supply configuration in the flow direction, so that the electric field lines and space charge density are asymmetrically distributed along the flow direction. This forms a Coulomb volume force component along the main flow direction in the non-Newtonian dielectric liquid, which induces a flow distribution that tends to be a plunger flow in the straight section of the rectangular cross-section and enhances the heat transfer of the near-wall thermal boundary layer.

4. The electric field-enhanced anti-disturbance heat dissipation channel structure for marine electronic equipment according to claim 1, characterized in that: The emitter of the coaxial annular electrode pair is a central columnar electrode arranged along the axis of the circular cross-section segment, and the collector is an annular electrode arranged coaxially with the circular cross-section segment. The central columnar electrode is positioned on the central axis of the circular cross-section segment by an insulating support, and the annular electrode is attached and fixed to the inner wall of the circular cross-section segment. The central columnar electrode and / or the annular electrode are segmented along the axial direction of the circular cross-section segment, and there is an axial potential difference or polarity bias between adjacent electrode segments, so that a radial electric field and a space charge distribution that varies along the axial direction are formed in the circular cross-section segment, thereby generating a Coulomb volume force with an axial component to induce the formation of an axisymmetric swirling or circulating field.

5. The electric field-enhanced anti-disturbance heat dissipation channel structure for marine electronic equipment according to claim 1, characterized in that: The plate-plate electrode pairs and the coaxial ring electrode pairs are arranged alternately along the flow direction of the loop-shaped microchannel and are uniformly connected to the high-voltage DC power supply through multiple branch high-voltage insulated leads. The high-voltage DC power supply has at least two independently adjustable high-voltage output channels, which provide working voltages to the plate-plate electrode pairs and the coaxial ring electrode pairs respectively and are independently adjusted by the electronic control unit. The plate-plate electrode pairs form volume forces with flow components in the straight section of the rectangular cross-section by flow direction misalignment, segmented power supply, or polarity bias. The coaxial ring electrode pairs form volume forces with axial components in the circular cross-section section by axial segmentation or polarity bias. The transition section is an electrode-free section that spatially decouples the electric fields formed by the two types of electrodes.

6. The electric field-enhanced anti-disturbance heat dissipation channel structure for marine electronic equipment according to claim 1, characterized in that: The non-Newtonian dielectric liquid is an electronic fluorinated liquid or transformer oil modified with cationic polyacrylamide, and is a shear-thinning viscoelastic non-Newtonian fluid. Its volume ratio is: 95-98 parts of basic dielectric liquid, 1-4 parts of cationic polyacrylamide, and 0.5-1 parts of hydrophobic nano silica particles.

7. The electric field-enhanced anti-disturbance heat dissipation channel structure for marine electronic equipment according to claim 1, characterized in that: The working fluid compensation unit includes a closed-loop liquid storage tank, a pressure compensator, and connecting pipelines. The closed-loop liquid storage tank is connected to the inlet and outlet ends of the loop-shaped microchannel via the connecting pipelines. The pressure compensator is connected to the closed-loop liquid storage tank. The connecting pipelines are equipped with insulated and sealed joints. The outer wall of the closed-loop liquid storage tank and / or the lower surface of the high thermal conductivity heat dissipation substrate form a heat dissipation surface that is thermally coupled with the ship mounting base, cold plate, or shell.

8. A method for enhancing the heat dissipation of marine electronic equipment by electric field enhancement, characterized in that: The heat dissipation channel structure according to any one of claims 1 to 7 includes the following steps: injecting the non-Newtonian dielectric liquid into the loop-shaped microchannel through a working fluid compensation unit and removing air bubbles; acquiring the IGBT junction temperature through a junction temperature monitoring module and transmitting it to the electronic control unit; applying a high-voltage DC electric field to the plate-plate electrode pair and the coaxial annular electrode pair respectively through a high-voltage DC power supply, causing space charges to form in the non-Newtonian dielectric liquid and, under the action of Coulomb volume force, forming a directional flow tending towards a plunger flow distribution in the straight section of the rectangular cross-section, and in the circular... The cross-sectional section forms an axisymmetric swirling or circulating flow, which circulates directionally along the loop-shaped microchannel. The non-Newtonian dielectric liquid absorbs and carries away the heat conducted from the IGBT module to the high thermal conductivity heat dissipation substrate. The heat is released outward through the high thermal conductivity heat dissipation substrate, the outer wall of the closed liquid storage tank, and / or the heat dissipation surface coupled with the ship's cooling structure. The electric field parameters of the plate-to-plate electrode pair and the coaxial annular electrode pair are independently adjusted by the electronic control unit according to the IGBT junction temperature and the ship's engine room operating conditions. The pressure fluctuations in the closed loop are compensated by the working fluid compensation unit.

9. The method for enhancing the heat dissipation of marine electronic equipment by electric field enhancement according to claim 8, characterized in that: The working electric field strength of the plate-plate electrode pair and the coaxial ring electrode pair is 1 to 5 kV / mm, the flow Reynolds number of the non-Newtonian dielectric liquid driven by Coulomb volume force is 50 to 500, and the junction temperature closed-loop control response time of the electronic control unit is preferably no more than 10 ms.

10. The method for enhancing the heat dissipation of ship electronic equipment by electric field enhancement according to claim 9, characterized in that: When the heat flux density of IGBT is 50-150 W / cm², the electric field strength is controlled at 1-3 kV / mm; when the heat flux density of IGBT is 150-300 W / cm², the electric field strength is controlled at 3-5 kV / mm; when the ambient temperature is below 0℃, the electric field strength is increased by 0.5-1 kV / mm based on the corresponding heat flux density operating condition.

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