阅读说明：本技术 一种电场控制供液的离子液体电喷推力器 (Ionic liquid electric spraying thruster for electric field control liquid supply ) 是由 武志文 孙伟 孙振宁 韩雨宁 王云冰 于 2021-02-22 设计创作，主要内容包括：本发明涉及一种电场控制供液的离子液体电喷推力器,属于微纳卫星微推进技术领域。本发明包括储液槽、覆盖有疏水介电层的铜片、用于控制铜片距离的绝缘垫片、上壳体、发射极、提取极。该推力器使用电场提高离子液体与多孔介质型发射极之间浸润性,同时通过电场来控制离子液体在毛细管道中的流动特性,可实现推进剂的主动供给,提高离子液体电喷推力器发射的稳定性和寿命,适用于低功率微纳卫星的阻力补偿,位置保持,姿态控制等任务需求。(The invention relates to an ionic liquid electric spraying thruster for controlling liquid supply through an electric field, and belongs to the technical field of micro-propulsion of micro-nano satellites. The invention comprises a liquid storage tank, a copper sheet covered with a hydrophobic dielectric layer, an insulating gasket for controlling the distance of the copper sheet, an upper shell, an emitter and an extraction electrode. The thruster improves the wettability between ionic liquid and a porous medium type emitting electrode by using an electric field, controls the flow characteristic of the ionic liquid in a capillary pipeline by the electric field, can realize active supply of a propellant, improves the emitting stability and the service life of the ionic liquid electric spraying thruster, and is suitable for the task requirements of low-power micro-nano satellite on resistance compensation, position maintenance, attitude control and the like.)

1. An electric field control supplies ionic liquid electricity of liquid and spouts thrustor which characterized in that: the device comprises a liquid storage tank, a copper sheet covered with a hydrophobic dielectric layer, an insulating gasket for controlling the distance of the copper sheet, an upper shell, an emitter and an extraction electrode;

the copper sheet covered with the hydrophobic dielectric layer is fixed with the insulating gasket in an interference fit manner through the groove in the liquid storage tank and is vertically suspended in the liquid storage tank; the emitter is fixed through the upper shell groove; the extraction electrode is fixed by an insulating screw and keeps a certain distance from the emitter; the two copper sheets covered with the hydrophobic dielectric layer form a group, and the two copper sheets and the liquid storage tank form a capillary pipeline for ionic liquid to flow; in an initial state, the ionic liquid does not infiltrate the capillary channel due to the influence of the hydrophobic dielectric layer, then the wettability of the ionic liquid and the capillary channel is improved through the electric field, and meanwhile, the flowing characteristic of the ionic liquid in the capillary channel is controlled through the electric field, so that the active supply of the ionic liquid is realized.

2. The electric field controlled liquid feeding ionic liquid electrospray thruster of claim 1, wherein: the flowing speed of the liquid is controlled by controlling the distance between the two copper sheets and the voltage loaded on the two copper sheets, and the speed v satisfies the relational expression

Wherein rho is the density of the ionic liquid; gamma is the surface tension coefficient of the ionic liquid, mu is the dynamic viscosity of the ionic liquid, D is the distance between two copper sheets, h is the height of the copper sheets, and theta₀Is the initial contact angle, epsilon, of the ionic liquid with the hydrophobic dielectric layer₀Is a vacuum dielectric constant of ∈_rIs the dielectric constant of the dielectric layer material, d is the thickness of the dielectric layer, and U is the voltage loaded on the two copper sheets.

3. The electric field controlled liquid feeding ionic liquid electrospray thruster of claim 1, wherein: the hydrophobic dielectric layer is composed of a dielectric layer with micron-scale thickness and a hydrophobic layer with nano-scale thickness.

4. The electric field controlled liquid feeding ionic liquid electrospray thruster of claim 1 or 3, wherein: the hydrophobic dielectric layer is made of insulating materials and fluorine-containing polymers.

5. The electric field controlled liquid feeding ionic liquid electrospray thruster of claim 4, wherein: the insulating material includes: silicon dioxide, N-type parylene; the fluoropolymer comprises: teflon, fluorinated polyethylene, fluorocarbon wax.

6. The electric field controlled liquid feeding ionic liquid electrospray thruster of claim 1, wherein: the emitter is a porous material with arrayed tips.

7. The electric field controlled liquid feeding ionic liquid electrospray thruster of claim 1, wherein: the number of the copper sheet groups is at least one.

8. The working method of the electric field controlled liquid feeding ionic liquid electrospray thruster of claim 1, characterized in that: in an initial state, the ionic liquid and the hydrophobic dielectric layer are in a non-wetting state and cannot flow along a capillary channel formed by the two copper sheets under the capillary action; when the device needs to work, the two copper sheets are connected with a power supply, the ionic liquid is grounded, the surface free energy of the hydrophobic dielectric layer is reduced under the action of an electric field, the ionic liquid and the hydrophobic dielectric layer are changed into a soaking state, and the ionic liquid and the hydrophobic dielectric layer flow along a capillary pipeline under the capillary action to gradually soak the emitter; after the emitter is completely soaked by the ionic liquid, the power supply of the copper sheet is turned off, and the ionic liquid is not grounded; applying a high electric field between the emitter and the extraction electrode, forming a Taylor cone by the ionic liquid at the tip of the emitter, and then emitting charged particles which can be charged liquid drops or pure ions or a mixture of the charged liquid drops and the pure ions, wherein the charged particles are accelerated and sprayed out in the electric field to generate thrust; after the ion liquid is operated for a period of time, the ion liquid stored in the emitting electrode is reduced, so that the thrust is reduced, the steps are repeated, the active liquid supply of the ion liquid electric spraying thruster is realized, the emitting stability is improved, and the service life is prolonged.

Technical Field

The invention relates to an ionic liquid electric spraying thruster for controlling liquid supply through an electric field, and belongs to the technical field of micro-propulsion of micro-nano satellites.

Background

The cost is low, the development period is short, the emission is flexible, and the method is the main advantages of the micro-nano satellite, and the micro-nano satellite has wide application and wide prospect in the fields of communication, remote sensing, earth observation, space test and the like. Because the micro-nano satellite is limited by total power, mass and volume, a propulsion system of the micro-nano satellite needs to have the characteristics of low power consumption, light weight, small volume, long service life, accurate thrust and the like. The Ionic Liquid Electrospray Thruster (ILET) has the characteristics of small volume, light weight, high specific impulse, high thrust precision and the like, can meet the requirements of a micro-nano satellite on a propulsion system, and is one of ideal propulsion systems of the micro-nano satellite. However, the liquid working medium is used as a propellant, and the traditional porous medium type ionic liquid electric spraying thruster has the defect of emission stability and service life because the thrust is reduced after the liquid working medium is consumed to a certain degree.

Disclosure of Invention

The invention aims to improve the emission stability and the service life of an ionic liquid electrospray thruster and provide an ionic liquid electrospray thruster for controlling liquid supply by an electric field. The thruster improves the wettability between the ionic liquid and the capillary type emitting electrode by using an electric field, controls the flow characteristic of the ionic liquid in the capillary pipeline by the electric field, can realize active supply of the propellant, and improves the emitting stability and service life of the ionic liquid electronic injection thruster.

The purpose of the invention is realized by the following technical scheme.

An ionic liquid electric spraying thruster for controlling liquid supply by an electric field comprises a liquid storage tank, a copper sheet covered with a hydrophobic dielectric layer, an insulating gasket for controlling the distance of the copper sheet, an upper shell, an emitting electrode and an extraction electrode;

the copper sheet covered with the hydrophobic dielectric layer is fixed with the insulating gasket in an interference fit manner through the groove in the liquid storage tank and is vertically suspended in the liquid storage tank; the emitter is fixed through the upper shell groove; the extraction electrode is fixed by an insulating screw and keeps a certain distance from the emitter; the two copper sheets covered with the hydrophobic dielectric layer form a group, and the two copper sheets and the liquid storage tank form a capillary pipeline for ionic liquid to flow; in an initial state, the ionic liquid does not infiltrate the capillary channel due to the influence of the hydrophobic dielectric layer, then the wettability of the ionic liquid and the capillary channel is improved through the electric field, and meanwhile, the flowing characteristic of the ionic liquid in the capillary channel is controlled through the electric field, so that the active supply of the ionic liquid is realized.

The flowing speed of the liquid is controlled by controlling the distance between the two copper sheets and the voltage loaded on the two copper sheets, and the speed v satisfies the relational expression

Wherein rho is the density of the ionic liquid; gamma is the surface tension coefficient of the ionic liquid, mu is the dynamic viscosity of the ionic liquid, D is the distance between two copper sheets, h is the height of the copper sheets, and theta₀Is the initial contact angle, epsilon, of the ionic liquid with the hydrophobic dielectric layer₀Is a vacuum dielectric constant of ∈_rIs the dielectric constant of the dielectric layer material, d is the thickness of the dielectric layer, and U is the voltage loaded on the two copper sheets.

The hydrophobic dielectric layer is composed of a dielectric layer with micron-scale thickness and a hydrophobic layer with nano-scale thickness.

The hydrophobic dielectric layer is made of insulating materials and fluorine-containing polymers.

The insulating material includes: silicon dioxide, N-type parylene; the fluoropolymer comprises: teflon, fluorinated polyethylene, fluorocarbon wax.

The emitter is a porous material with arrayed tips.

The number of the copper sheet groups is at least one.

In the working method of the ionic liquid electric spraying thruster for controlling liquid supply by the electric field, in an initial state, because the ionic liquid and the hydrophobic dielectric layer are in a non-wetting state, the ionic liquid cannot flow along a capillary channel formed by two copper sheets under the capillary action; when the device needs to work, the two copper sheets are connected with a power supply, the ionic liquid is grounded, the surface free energy of the hydrophobic dielectric layer is reduced under the action of an electric field, the ionic liquid and the hydrophobic dielectric layer are changed into a soaking state, and the ionic liquid and the hydrophobic dielectric layer flow along a capillary pipeline under the capillary action to gradually soak the emitter; after the emitter is completely soaked by the ionic liquid, the power supply of the copper sheet is turned off, and the ionic liquid is not grounded; applying a high electric field between the emitter and the extraction electrode, forming a Taylor cone by the ionic liquid at the tip of the emitter, and then emitting charged particles which can be charged liquid drops or pure ions or a mixture of the charged liquid drops and the pure ions, wherein the charged particles are accelerated and sprayed out in the electric field to generate thrust; after the ion liquid is operated for a period of time, the ion liquid stored in the emitting electrode is reduced, so that the thrust is reduced, the steps are repeated, the active liquid supply of the ion liquid electric spraying thruster is realized, the emitting stability is improved, and the service life is prolonged.

The copper sheet covered with the hydrophobic dielectric layer is fixed with the insulating gasket in an interference fit manner through the groove in the liquid storage tank and is vertically suspended in the liquid storage tank; the emitter is fixed through the upper shell groove; the extraction pole is fixed by an insulating screw and keeps a certain distance with the emitter. The hydrophobic dielectric layer is made of micron-sized N-type parylene and nanometer-sized Teflon. The emitter is a porous material with arrayed tips.

The copper sheet covered with the hydrophobic dielectric layer is T-shaped, and the protruding part and the liquid storage groove are in interference fit through the insulating gasket, so that the assembly is tight.

The upper shell is internally convex to position and fix the emitter, so that the emitter is isolated from the external environment, the emitter is protected, and the distance between the emitter and the extraction electrode is controlled through the distance between the position of the inner protrusion of the shell and the outer wall of the shell.

In an initial state, the ionic liquid and the hydrophobic dielectric layer are in a non-wetting state and cannot flow along a capillary channel formed by the two copper sheets under the capillary action. When the device needs to work, the two copper sheets are connected with a power supply, the ionic liquid is grounded, the surface free energy of the hydrophobic dielectric layer is reduced under the action of an electric field, the ionic liquid and the hydrophobic dielectric layer are changed into a soaking state, and the ionic liquid and the hydrophobic dielectric layer flow along the capillary pipeline under the capillary action to gradually soak the emitter. And after the emitter is completely soaked by the ionic liquid, the power supply of the copper sheet is turned off, and the ionic liquid is not grounded. A high electric field is applied between the emitter and the extraction electrode, the ionic liquid at the tip of the emitter forms a Taylor cone, charged particles, which can be charged liquid drops or pure ions or a mixture of the charged particles and the pure ions, are emitted, and the charged particles are accelerated and sprayed out in the electric field to generate thrust. After the ion liquid is operated for a period of time, the ion liquid stored in the emitting electrode is reduced, so that the thrust is reduced, the steps are repeated, the active liquid supply of the ion liquid electric spraying thruster is realized, the emitting stability is improved, and the service life is prolonged.

Advantageous effects

1. The invention discloses an ionic liquid electronic injection thruster for controlling liquid supply by an electric field, which controls the wettability of ionic liquid and a capillary pipeline by the electric field, and controls the flow characteristic of the ionic liquid in the capillary pipeline by the electric field so as to realize the active supply of the ionic liquid.

2. After the traditional porous medium type ionic liquid electrospray thruster works for a period of time, the ionic liquid stored in the emitting electrode is reduced, so that unstable emission and reduced thrust are caused. The ionic liquid electric spraying thruster for controlling liquid supply by the electric field can supplement the ionic liquid of the emitting electrode in a mode of applying the electric field, and improves the emitting stability.

3. According to the ionic liquid electric spraying thruster for controlling liquid supply through the electric field, disclosed by the invention, the ionic liquid is supplied to the emitting electrode through the liquid storage tank, so that the total amount of the propellant carried by the thruster can be greatly increased, and the service life of the thruster is prolonged.

Drawings

FIG. 1 is a schematic diagram of an electric field controlled liquid feeding ionic liquid electrospray thruster;

fig. 2 is a schematic view of a fixing mode of a liquid storage tank and a copper sheet covered with a hydrophobic dielectric layer.

Wherein: 1-a liquid storage tank, 2-an upper shell, 3-a copper sheet covered with a hydrophobic dielectric layer, 4-an emitter, 5-an extraction electrode and 6-an insulating gasket for controlling the distance of the copper sheet.

Detailed Description

For a better understanding of the objects and advantages of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings and examples.

Example 1:

the implementation discloses an ionic liquid electric spray thruster for controlling liquid supply through an electric field, which comprises a liquid storage tank 1, a copper sheet 3 covered with a hydrophobic dielectric layer, an insulating gasket 6 used for controlling the distance of the copper sheet, an upper shell 2, an emitter 4 and an extraction electrode 5.

The liquid storage tank 1 is made of insulating materials, and is 30mm long, 30mm wide, 10mm high and 2mm thick at the bottom. Grooves are designed on two opposite side walls, the length is 5mm, the width is 1.6mm, and the depth is 4 mm.

The hydrophobic dielectric layer is composed of N-type parylene with the thickness of 10 mu m and 500nm of Teflon, and has good dielectric and hydrophobic properties.

The ionic liquid is selected from 1-ethyl-3-methylimidazole tetrafluoroborate (EMI-BF)₄) The contact angle with the hydrophobic dielectric layer in the initial state is 100 °.

The copper sheet 3 covered with the hydrophobic dielectric layer is T-shaped, and the protruding section corresponds to the liquid storage groove. The thickness is 0.5mm, the height is 6mm, and the distance from the bottom of the liquid storage tank is 2 mm. 3, the copper sheets 3 covered with the hydrophobic dielectric layer are arranged at equal intervals.

The thickness of the insulating gasket 6 for controlling the distance of the copper sheets can be adjusted to 0.4 mm. The distance between two T-shaped copper sheets 3 covered with hydrophobic dielectric layers is adjusted through the thickness of an insulating gasket 6 for controlling the distance between the copper sheets, and the T-shaped copper sheets are in interference fit with grooves in the side wall of the liquid storage tank 1 to form a capillary pipeline with the periphery closed.

The upper shell 2 is internally convex to position and fix the emitter, and simultaneously, the emitter 4 is isolated from the external environment, the emitter 4 is protected, and the distance between the emitter 4 and the extraction electrode 5 is controlled through the internally convex position.

The number of tips of the array of the emitter electrodes 4 was 10 × 10, and charged particles were ejected from the cavities corresponding to the extraction electrodes 5.

The working process is as follows: in an initial state, the ionic liquid in the liquid storage tank 1 and the copper sheets 3 covered with the hydrophobic dielectric layers are in a non-wetting state, so that the ionic liquid cannot rise along a capillary channel formed by the two copper sheets under the capillary action. When the device needs to work, the two copper sheets are connected with a power supply, the ionic liquid is grounded, the surface free energy of the hydrophobic dielectric layer is reduced under the action of an electric field, the ionic liquid and the hydrophobic dielectric layer are changed into a soaking state, and the ionic liquid and the hydrophobic dielectric layer rise along the capillary channel under the capillary action to gradually soak the emitter 4. And after the emitter 4 is completely soaked by the ionic liquid, the power supply of the copper sheet is turned off, and the ionic liquid is not grounded. Applying a high electric field between the emitter 4 and the extraction electrode 5, the ionic liquid at the tip of the emitter 4 forms a Taylor cone, and then emitting charged particles, which may be charged liquid drops, or pure ions, or a mixture of the two, wherein the charged particles are accelerated and sprayed out in the electric field to generate thrust. After working for a period of time, the ionic liquid stored in the emitter 4 is reduced, so that the thrust is reduced, and the steps are repeated, so that the active liquid supply of the ionic liquid electrospray thruster is realized.

The above detailed description is intended to illustrate the objects, aspects and advantages of the present invention, and it should be understood that the above detailed description is only exemplary of the present invention and is not intended to limit the scope of the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.