A fluid transportation device based on a microgravity environment

Abstract

The present application discloses a fluid transport device based on a microgravity environment, which includes a surface tension liquid storage tank with a microchannel diversion groove and a sealed top cover. A fluid port is provided on the top cover, and a keyway is designed inside the fluid port. A layer of interdigital electrode array is deposited on the bottom plate through a sputtering process. Subsequently, the electrode plate is fitted with the keyway on the inner wall of the flow channel, and the pin ends of the interdigital electrode array on the electrode plate are connected to a high-voltage and low-current DC power supply. By regulating the magnitude of the voltage, the liquid supply flow rate of the dielectric liquid in the tank is controlled. This device is used for the controllable and effective supply of dielectric liquids (such as lubricating oil) in the space microgravity environment. The electrohydrodynamic driving electrodes are integrated into the surface tension liquid storage tank, and circumferentially distributed microchannel grooves are designed on the inner surface of the liquid storage tank. In the case of weightlessness, the automatic collection of liquid is realized by using surface tension, effectively realizing space fluid management, and through the electric field action of the driving electrodes, the dielectric liquid forms a directional flow.

Description

Technical Field

[0001] This application relates to the field of microfluidic space management in a microgravity environment, and specifically relates to a fluid transport device based on a microgravity environment. Background Technique

[0002] As is well known, the behavior of fluids in a microgravity environment is very different from that on the ground. Currently, space fluid management technologies are mainly applied to the heat dissipation and cooling of aerospace components. Bearings are key components for functions such as steering and driving in spacecraft. Good bearing lubrication in spacecraft is of great significance for the high reliability and long healthy life of bearings. Currently, the traditional lubrication methods for spacecraft bearings are mostly passive oil supply [Sun Xiaobo, Wang Feng, Ge Shijun, Zhang Hongyi, Wang Zijun. Lubrication Technology for Long-Life Aerospace Bearings [J]. Bearing, 2012(03): 60-64.]. Such methods cannot meet the quantitative supply of lubricating oil, and the reliability is not high, or a series of complex rigid oil circuits are required, which severely restricts the further lightweight development of spacecraft. Aiming at the problems of heavy mass, large volume, and complex pipelines in the traditional satellite bearing lubrication system, the present invention proposes a new type of micro-drive control technology for lubricating oil based on microfluidic technology, and develops a controllable liquid supply method for lubricating oil for lightweight satellite bearings to achieve efficient, reliable and micro-scale transport of lubricating oil.

[0003] How to ensure the active transportation of a quantitative amount of lubricating oil for spacecraft bearings in a microgravity environment is a difficult problem that needs to be solved urgently in current research. Micropumps can be classified into mechanical and non-mechanical types according to their structures. Piezoelectric micropumps are based on the inverse piezoelectric effect of piezoelectric crystals, converting the electrical effect into the movement of the vibrating membrane [Mindlin R.D..High frequency vibrations of crystal plates[J].Quarterly of Applied Mathematics,1961,19(1).]. Pneumatic micropumps use compressed air as the power source, causing volume changes through the reciprocating deformation of the thin film [Huang C W,Huang S B,Lee GB.Pneumatic micropumps with serially connected actuation chambers[J].Journal of micromechanics and microengineering,2006,16(11):2265.]. The above mechanical pumps all drive the liquid by causing the volume of the pump chamber to change periodically through the movement of moving parts, and are prone to problems such as fatigue and wear during long-term operation. Electroosmotic pumps and magnetohydrodynamic pumps are suitable for driving liquids with relatively high electrical conductivities. Surface tension micropumps drive the liquid flow based on the action of surface tension, but they cannot guarantee accurate driving flow rates and sufficient driving pressures. Lubricating oil itself has a relatively low electrical conductivity and a high viscosity, and its flow behavior in the oil storage chamber is difficult to predict in a weightless environment. When the liquid filling rate is low, it cannot be guaranteed that the lubricating oil in the oil storage chamber can gather at the bottle mouth, resulting in a phenomenon of liquid supply stagnation. Ordinary lubrication devices are difficult to meet the requirements of micro-lubrication of spacecraft bearings in the space environment. Therefore, how to design an efficient and simple automatic lubricating oil supply device is a problem that needs to be solved urgently by those in this field. Summary of the Invention

[0004] In view of the problems of large mass, complex structure, poor controllability, etc. of traditional spacecraft bearing lubrication systems, the purpose of the present invention is to propose an active transportation device for spacecraft bearing lubricating oil that can achieve stable liquid supply, can control the liquid supply flow rate by changing the magnitude of the working voltage according to actual needs, and can change the flow direction of the lubricating oil or stop it by changing the voltage polarity or cutting off the power supply.

[0005] The present application provides a fluid transport device based on a microgravity environment, including: a liquid storage tank with a diversion groove penetrating through the inner wall at the bottom and the opening, the diversion groove being uniformly arranged on the circumferential inner wall of the liquid storage tank; and an EHD driving component arranged in the liquid storage tank, the EHD driving component being provided with a support column, an electrode plate, a wide electrode, a narrow electrode, and an electrode lead. An axial slot is provided on the outer periphery of the support column, the electrode plate is fixed on the slot, and an interdigital electrode array composed of a wide electrode and a narrow electrode is respectively arranged on the electrode plate. The wide electrodes and the narrow electrodes on each electrode plate are respectively connected with electrode leads; and a top cover is arranged at the opening end of the liquid storage tank. A flow port is provided in the center of the top cover, and a key groove corresponding to the electrode plate is provided on the inner wall of the flow port, and the electrode plate is correspondingly connected with the key groove; the top cover is provided with a connection end.

[0006] In some embodiments, the radial cross-section of the diversion groove is in a "V" shape, the angle of the "V" shaped diversion groove is 30° - 60°, and the depth is 1 - 3 mm.

[0007] In some embodiments, the surface roughness Sa of the inner wall of the liquid storage tank is 0.1 - 1 um.

[0008] In some embodiments, the interdigital electrode array is symmetrically arranged on both sides of the electrode plate and is in a comb shape.

[0009] In some embodiments, the width of the narrow electrode is not less than 0.5 mm, and the ratio of the width of the narrow electrode to the width of the wide electrode is 1:1.5 - 3.

[0010] In some embodiments, the inter-electrode spacing of the interdigital electrode array is not less than 0.1 mm, and the ratio of the inter-electrode spacing to the inter-electrode pair spacing is 1:4 - 6.

[0011] In some embodiments, there are 6 - 12 electrode plates, and the included angle between adjacent electrode plates is 30° - 60°.

[0012] In some embodiments, there are at least 10 pairs of electrodes on the electrode plate, and the length of the interdigital electrode array is not greater than the length of the electrode plate.

[0013] In some embodiments, a mortise and tenon structure is used for connecting the liquid storage tank and the top cover.

[0014] In some embodiments, the wide electrode is connected to high voltage on the outer circle of the electrode plate, and the narrow electrode is grounded on the inner circle of the electrode plate, and the two are arranged alternately.

[0015] Advantages of the present application: By providing a surface tension liquid storage tank with a microchannel diversion groove and a sealed top cover, a flow port is opened on the top cover, and a keyway is designed inside the flow port. A finger electrode array is deposited on the bottom plate through a sputtering process. Subsequently, the electrode plate is fitted with the keyway on the inner wall of the flow channel, and the pin ends of the finger electrode array on the electrode plate are connected to a DC power supply with high voltage and low current. By adjusting the magnitude of the voltage, the liquid supply flow rate of the dielectric liquid in the tank is controlled. This device is used for the controllable and effective supply of dielectric liquids (such as lubricating oil) in the microgravity environment of space. The electrohydrodynamic driving electrode is integrated into the surface tension liquid storage tank, and microchannel grooves distributed in a circle are designed on the inner surface of the liquid storage tank. In the case of weightlessness, the surface tension is utilized to achieve the automatic collection of the liquid, effectively realizing space fluid management. Through the electric field action of the driving electrode, the dielectric liquid forms a directional flow. The lubrication system used is simplified, and the storage end and the driving end of the lubricating oil are integrated innovatively. While ensuring the controllability of the oil supply volume, the complexity and redundancy of the entire liquid supply device are greatly avoided, which is beneficial to the further lightweight development of spacecraft. This solution fully considers the fluid behavior in the microgravity environment of space. By designing diversion grooves at a certain angle and utilizing the action of the liquid's own surface tension, the flow management of the lubricating oil is achieved, and sufficient driving liquid can be provided for the EHD driving component even at a relatively low liquid filling rate.

[0016] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specific embodiments of the present application are specifically exemplified. Description of the Drawings

[0017] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. And in all the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0018] Figure 1 is a schematic structural diagram of a fluid transport device based on a microgravity environment for some embodiments of the present application;

[0019] Figure 2 is a schematic internal structure diagram of a fluid transport device based on a microgravity environment for some embodiments of the present application;

[0020] Figure 3 is a partial structural schematic diagram of the EHD driving component mentioned in the solution of the present invention;

[0021] Figure 4It is a sectional schematic diagram of a fluid transportation device based on a microgravity environment mentioned in the solution of the present invention;

[0022] Figure 5 It is a schematic diagram of the support column mentioned in the solution of the present invention;

[0023] Figure 6 It is a schematic diagram of the liquid storage tank mentioned in the solution of the present invention;

[0024] Figure 7 It is a schematic diagram of the interdigital electrode array of the electrode plate mentioned in the solution of the present invention;

[0025] Figure 8 It is a schematic diagram of the top cover mentioned in the solution of the present invention;

[0026] Figure 9 It is a schematic diagram of the principle of the EHD driving component mentioned in the solution of the present invention.

[0027] The reference numerals in the drawings in the specific embodiments are as follows:

[0028] Liquid storage tank 1; Flow guide groove 11; EHD driving component 2; Support column 21; Slot 211; Electrode plate 22; Wide electrode 23; Narrow electrode 24; Electrode lead 25; Interdigital electrode array 26; Top cover 3; Flow port 31; Key groove 32; Connection end 4. Specific embodiments

[0029] Hereinafter, embodiments of the technical solution of the present application will be described in detail with reference to the drawings. The following embodiments are only used to illustrate the technical solution of the present application more clearly, and therefore are only examples and cannot be used to limit the protection scope of the present application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion.

[0031] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, "a plurality" means more than two unless otherwise specifically defined.

[0032] Reference to "embodiments" in this specification means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase may appear in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive of other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0033] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this text generally represents an "or" relationship between the associated objects before and after.

[0034] In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0035] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of the present application.

[0036] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may also be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0037] Please refer to Figures 1-9, A fluid transportation device based on a microgravity environment provided by some embodiments of the present application includes: a liquid storage tank 1 with a diversion groove 11 penetrating through the inner wall at the bottom and the opening, and the diversion groove 11 is uniformly arranged on the circumferential inner wall of the liquid storage tank 1; and an EHD driving assembly 2 arranged in the liquid storage tank 1, the EHD driving assembly 2 is provided with a support column 21, an electrode plate 22, a wide electrode 23, a narrow electrode 24 and an electrode lead 25. An axial slot 211 is provided on the outer periphery of the support column 21, the electrode plate 22 is fixed in the slot 211, and an interdigital electrode array 26 composed of a wide electrode 23 and a narrow electrode 24 is respectively arranged on the electrode plate 22. The wide electrodes 23 and the narrow electrodes 24 on each electrode plate 22 are respectively connected by an electrode lead 25; and a top cover 3 is arranged at the opening end of the liquid storage tank 1. A flow port 31 is provided at the center of the top cover 3, and a keyway 32 corresponding to the electrode plate 22 is provided on the inner wall of the flow port 31, and the electrode plate 22 is connected to the keyway 32 in a one-to-one correspondence; the top cover 3 is provided with a connection end 4.

[0038] The function of the diversion groove 11 is to introduce the lubricating oil not at the bottom end of the container into the bottom of the liquid storage tank 1 by the action of surface tension. Due to the influence of weightlessness in space, the lubricating oil will not always be at the bottom of the liquid storage tank 1, and the distribution of the oil liquid will be uncertain when the spacecraft accelerates or changes its orbit; then the lubricating oil is transported to the opening of the liquid storage tank 1 through the driving action of the electrode plate 22. Both the electrode plate 22 and the diversion groove 11 are evenly distributed in a circle. Increasing the number of electrode plates 22 can enhance the driving effect of the lubricating oil, and increasing the number of diversion grooves 11 can increase the probability of the lubricating oil not at the bottom of the liquid storage tank 1 flowing back. The interdigital electrode array 26 is deposited on the electrode plate by sputtering.

[0039] In some embodiments, the radial cross-section of the diversion groove 11 is in a "V" shape, the angle of the "V"-shaped diversion groove 11 is 30° - 60°, and the depth is 1 - 3 mm.

[0040] The diversion groove 11 is a V-shaped groove, and the included angle refers to the angle of the V. The determination of this angle is based on the Concus-Finn formula. If the sum of the solid-liquid contact angle and half of the inner angle of the diversion groove 11 is less than 90°, then in the case of weightlessness, the liquid will flow infinitely along the diversion groove 11 under the Laplace pressure gradient, which lays the foundation for providing a continuous liquid flow for the front-end EHD driving assembly 2.

[0041] The angle of the diversion groove 11 is mainly considered based on the solid-liquid contact angle. If the solid-liquid contact angle is small, the included angle of the diversion groove 11 can be relatively increased to meet the Concus-Finn formula, but the smaller the included angle of the diversion groove 11, the greater the processing difficulty, and the groove depth is selected based on the wall thickness.

[0042] In some embodiments, the surface roughness Sa of the inner wall of the liquid storage tank 1 is 0.1 - 1 um.

[0043] Through experimental research, the lubricating oil contact angle of a resin material with a Sa of approximately 0.183 μm was tested, and the result was approximately 12.12°. The lubricating oil contact angle of PMMA with a Sa of approximately 0.126 μm was tested, and the result was approximately 12.59°. The lubricating oil contact angle of PMMA with a Sa of approximately 0.071 μm was tested, and the result was approximately 10.00°. Reducing the surface roughness can reduce the solid-liquid contact angle. The requirement for roughness is limited within 1 μm. Considering processing economy, too low surface roughness has little effect on reducing the solid-liquid contact angle. Therefore, the roughness range is controlled between 0.1 μm and 1 μm, which not only meets the performance requirements but also conforms to economy.

[0044] Too high will cause the wettability of the liquid on the solid wall to deteriorate, the contact angle to increase, and affect the climbing effect of the oil under weightlessness. Too low requires more precise processing methods, increasing the manufacturing cost.

[0045] In some embodiments, the interdigitated electrode array 26 is symmetrically arranged on both sides of the electrode plate 22 and is in a comb shape.

[0046] In some embodiments, the narrow electrode width is not less than 0.5 mm, and the ratio of the narrow electrode width to the wide electrode width is 1:1.5 - 3. If it is not within this range, the flow direction cannot be changed by controlling the voltage polarity. The narrow electrode width is A, and the wide electrode width is B.

[0047] The narrow electrode width is preferably in the range of 0.5 mm - 1 mm. Excessive electrode width or electrode spacing cannot exert the low-voltage advantage of this device, and one of the factors restricting the development of traditional macro electrohydrodynamic conduction pumps is the need for a high-voltage (tens of kilovolts) power supply to provide a strong electric field.

[0048] In some embodiments, the interelectrode spacing of the interdigitated electrode array is not less than 0.1 mm, and the ratio of the interelectrode spacing to the interelectrode pair spacing is 1:4 - 6. The interelectrode spacing is S, and the interelectrode pair spacing is L.

[0049] The interelectrode spacing should not be less than 0.1 mm. Otherwise, at the microscale, the thickness of the electric double layer at the non-metallic solid wall is comparable to the electrode spacing, and the influence of the electric double layer on the flow inside the pump cannot be ignored, and the electrode structure needs to be adjusted to avoid the electric double layer effect.

[0050] Based on the EHD conduction principle, by designing an asymmetric electrode pair, the Coulomb forces acting on the positive and negative ions generated by dissociation are made unequal, thereby generating a resultant force pointing in the direction of the wide electrode 23. If the widths of the designed positive and negative electrodes are the same, no net flow will be generated. The narrow electrode 24 is grounded, and the wide electrode 23 is connected to a positive voltage. The inter-electrode spacing refers to the gap size between the positive and negative electrodes of the electrode pair, and the inter-pair spacing refers to the gap size between the wide electrode 23 of a pair of electrode pairs and the narrow electrode 24 of the adjacent next pair of electrode pairs. The inter-pair spacing should be greater than the inter-electrode spacing because the electric field generated between pairs weakens the flow, so it is necessary to appropriately increase the spacing. The number of electrode pairs determines the total length of the entire device. Increasing the number of electrode pairs can increase the pumping performance of the driving element, but it will make the entire device become lengthy, and the number of electrode pairs can be determined according to actual needs. Reducing the inter-electrode spacing can reduce the threshold voltage for driving the fluid.

[0051] The wide electrode 23 and the narrow electrode 24 form a pair of electrode pairs. The flow direction of the fluid is from the narrow electrode 24 (grounded) → the wide electrode 23 (high voltage) (effective working interval). Therefore, the outermost electrode (the first electrode counted from the outlet of the liquid storage tank 1 inward) is the wide electrode 23. Since the electrodes are arranged in pairs at the bottom, the bottommost one is naturally the narrow electrode 24.

[0052] Based on the selected processing technology, the minimum width of the narrow electrode 24 can reach 0.5 mm. Taking this value as a reference, other parameter values are determined. Through experimental comparison and verification, the selected width of the wide electrode 23, the inter-electrode spacing, and the inter-pair spacing of the electrodes can generate the optimal pumping performance at the lowest voltage under testing. Reducing the inter-electrode spacing can reduce the required driving voltage and increase the driving electric field strength. Selecting an appropriate inter-pair spacing can avoid generating an overly large field strength that obstructs the flow due to too small a distance, and can also avoid generating an overly large flow resistance due to too large a distance. Manufacturing electrodes smaller than 0.5 mm using other processing technologies will produce micro-scale effects and cannot generate sufficient driving force. In summary, the above parameter values are selected. Selecting other parameter values may also achieve a driving effect within a certain voltage range, but may require a higher voltage and the flow direction is uncontrollable. Increasing the number of electrode plates 22 and electrode pairs is to improve the driving ability. Each pair of electrodes is equivalent to a tiny power source, and the specific number can be determined according to actual needs. Since the flow direction of the lubricating oil is from the low-pressure end to the high-pressure end and the resultant force direction is pointing to the wide electrode 23, the wide electrode 23 needs to be set on the outside and connected to the high-voltage end.

[0053] In some embodiments, the electrode plate 22 is provided with 6 to 12 pieces, and the included angle between adjacent electrode plates is 30° to 60°.

[0054] The number of 22 electrode plates is too small to increase the driving force for the lubricating oil. If the number is too large, on the one hand, it will occupy the oil storage space of the liquid storage tank, and on the other hand, it is easy to cause mutual interference of the electric fields between the electrode plates.

[0055] In some embodiments, there are at least 10 pairs of electrodes on the electrode plate 22. The length of the interdigital electrode array is not greater than the length of the electrode plate.

[0056] Specifically, the number of pairs on both sides depends on the length of the liquid storage tank. The more the number of electrode pairs, the greater the driving force generated. Therefore, as many electrode pairs as possible are arranged on the electrode plate with a limited length.

[0057] In some embodiments, a mortise and tenon structure is used to connect the liquid storage tank 1 and the top cover 3.

[0058] The mortise and tenon structure is designed only for simple processing. If a threaded fit is used, the internal thread will affect the groove structure on the inner surface of the liquid storage tank 1 or the top cover 3.

[0059] The wide electrode is connected to high voltage on the outer circle of the electrode plate, and the narrow electrode is grounded on the inner circle of the electrode plate, and the two are arranged alternately.

[0060] Since the flow direction of the lubricating oil is always from the narrow end to the wide end and from the low-pressure end to the high-pressure end, by continuously increasing the supply voltage, the flow rate of the lubricating oil can be increased. When a large amount of liquid supply is required, the supply voltage is correspondingly increased. When the liquid supply needs to be stopped, the voltage polarity is reversed, and the lubricating oil flows back.

[0061] As shown in the Figures 1-9 attached figure, this embodiment discloses a fluid transport device based on a microgravity environment. The device mainly includes a surface tension liquid storage tank 1 part, a sealed top cover 3 part, and a conduction pump part of the EHD drive assembly 2.

[0062] The entire shell of the surface tension liquid storage tank 1 is made of ABS as the base material and is integrally manufactured by the FDM 3D printing method or processed by other methods such as mold processing. 8 diversion grooves 11 are evenly arranged on the inner wall circumference of the surface tension liquid storage tank 1. The inner wall of the diversion groove 11 is in a "V" shape with an included angle of 45° and a depth of 2 mm, which is used for directional diversion of liquid in a weightless environment. Subsequently, the inner wall of the surface tension liquid storage tank 1 is chemically polished for 1 h using acetone cold vapor at 25°C. The purpose is to reduce the surface roughness, improve the wetting degree of the lubricating oil on the inner wall surface, reduce the solid-liquid contact angle, and enable the lubricating oil to better climb along the groove in a weightless state.

[0063] The entire sealing top cover 3 is manufactured using the same process as the surface tension liquid storage tank 1. A flow port 31 with a pore diameter of 9 mm is opened at the center of the top cover 3, and eight key grooves 32 matching the electrode plates 22 are evenly arranged on the inner wall surface. An M13 ordinary metric external thread is machined on the outer circular surface of the top cover 3 for connection and mating with the bearing oil supply end.

[0064] The EHD driving component 2, whose interdigital electrode array 26 uses gold as the target material and is prepared on the bottom plate by sputtering technology. The dimensional parameters of the interdigital electrode array 26 are as follows: the width of the narrow electrode 24 is 0.5 mm, the width of the wide electrode 23 is 1.5 mm, the electrode pitch is 0.5 mm, the electrode pair pitch is 1.5 mm, and the total number of electrode pairs is 10 pairs. The eight prepared bottom plates with electrode patterns are inserted into the central support cylinder, and then the whole is inserted into the key grooves 32 of the corresponding sealing top cover 3 for mating connection. A mortise and tenon structure is used for sealing connection between the top cover 3 and the surface tension liquid storage tank 1.

[0065] The electrode leads 25 use copper wires to lead out the positive and negative common ends of the interdigital electrode array 26 respectively as the external pins for connecting the high-voltage power supply. The positive ends are connected together, and all the negative ends are connected together, and two external pins are led out through the reserved wire grooves on the sealing top cover 3.

[0066] In the interdigital electrodes of the present invention, the wide electrode 23 is connected to high voltage and the narrow electrode 24 is grounded to provide an electric field for the driving of the lubricating oil. When the lubricating oil neutral molecules are in an environment without electric field strength, the dissociation rate and the recombination rate reach equilibrium. When the electric field strength reaches a certain threshold, the dissociation rate is greater than the recombination rate. The positive and negative ions generated by dissociation migrate to the electrodes with opposite polarities under the action of the Coulomb force and form a heterogeneous charge layer near the electrodes. The ions will drag the neutral molecules to flow during the migration process. Since the asymmetric electrode arrangement will generate an uneven electric field, a resultant Coulomb force towards the wide electrode 23 is formed, so that the lubricating oil generates a net flow in a certain direction, and the principle is as shown in the appendix. Figure 9 as shown.

[0067] Eight flow guiding grooves 11 with an inner wall angle of 45° are designed on the inner surface of the surface tension liquid storage tank 1. According to the Concus-Finn principle of inner corner flow under microgravity, when the sum of the solid-liquid contact angle and half of the inner corner of the flow guiding groove 11 is less than 90°, then in a weightless environment, the liquid can flow infinitely along the inner corner of the flow guiding groove 11 driven by surface tension. Chemical polishing is carried out with acetone cold steam to reduce the contact angle between the liquid and the wall surface, improve the flow ability of the lubricating oil, and realize the management of the oil flow behavior in a microgravity environment, laying a foundation for providing continuous oil for the EHD driving component 2 under the condition of low liquid filling rate.

[0068] Apply high voltage externally across both ends of the electrode lead 25. Under the action of the electric field, the lubricating oil realizes directional flow. Control the liquid supply speed of the lubricating oil by changing the magnitude of the voltage, and the liquid supply can be reversed or stopped by reversing the voltage polarity or cutting off the power supply.

[0069] The lubricating oil is directly injected into the installed liquid storage tank 1 through a syringe. First, insert one end of the bottom plate with the interdigital electrode array 26 into the central support cylinder, and then insert the whole into the keyway 32 of the sealing top cover 3. Axially position it relying on the end wall of the keyway 32, and then cooperate the whole with the surface tension liquid storage tank 1 through the mortise and tenon structure on the sealing top cover 3. After completion, start oil injection with the opening facing upwards.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered within the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A fluid transportation device based on a microgravity environment, characterized in that, Comprising: A liquid storage tank and a flow guiding groove with an opening communicating to the bottom on its inner wall, the flow guiding grooves being uniformly arranged on the circumferential inner wall of the liquid storage tank; and an EHD driving assembly disposed in the liquid storage tank, the EHD driving assembly being provided with a support column, an electrode plate, a wide electrode, a narrow electrode and an electrode lead. An axial slot is provided on the outer periphery of the support column, the electrode plate is fixed on the slot, and an interdigital electrode array composed of a wide electrode and a narrow electrode is provided on the electrode plate. The wide electrodes and the narrow electrodes on each electrode plate are respectively provided with electrode leads; and a top cover is arranged at the opening end of the liquid storage tank. A flow port is provided at the center of the top cover, and a keyway is provided on the inner wall of the flow port corresponding to the electrode plate, and the electrode plate is correspondingly connected to the keyway; the top cover is provided with a connection end.

2. The fluid transportation device based on a microgravity environment according to claim 1, characterized in that, The radial cross-section of the flow guiding groove is in a "V" shape, the angle of the "V" shaped flow guiding groove is 30° to 60°, and the depth is 1-3 mm.

3. A fluid transportation device based on a microgravity environment according to claim 1, characterized in that, The surface roughness Sa of the inner wall of the liquid storage tank is 0.1-1 um.

4. A fluid transportation device based on a microgravity environment according to claim 1, wherein The interdigital electrode array is symmetrically arranged on both sides of the electrode plate and is in a comb shape.

5. A fluid transportation device based on a microgravity environment according to claim 1, characterized in that, The width of the narrow electrode is not less than 0.5 mm, and the ratio of the width of the narrow electrode to the width of the wide electrode is 1:1.5-3.

6. A fluid transportation device based on a microgravity environment according to claim 1 or 4, characterized in that, The inter-electrode spacing of the interdigital electrode array is not less than 0.1 mm, and the ratio of the inter-electrode spacing to the inter-electrode pair spacing is 1:4-6.

7. A fluid transportation device based on a microgravity environment according to claim 1 or 4, characterized in that, There are 6-12 electrode plates, and the included angle between adjacent electrode plates is 30°-60°.

8. A fluid transportation device based on a microgravity environment as claimed in claim 7, wherein, There are at least 10 pairs of electrodes on the electrode plate.

9. A fluid transportation device based on a microgravity environment according to claim 1 or 5, characterized in that, The wide electrodes are connected to high voltage on the outer circle of the electrode plate, and the narrow electrodes are grounded on the inner circle of the electrode plate, and the two are arranged alternately.

10. A fluid transport device based on a microgravity environment according to claim 3, characterized in that, The liquid storage tank and the top cover are connected by a mortise and tenon structure.

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