An air-breathing electric propulsion system

Abstract

The application provides an air-breathing electric propulsion system, which comprises a grid, an air inlet, a rectifying device and a helicon wave thruster body; the grid is the first device contacted by the incoming airflow, the bottom of which is connected with the front end of the air inlet, the inner wall of the air inlet is in a parabolic structure, and the rear end of the air inlet is connected with a long tube; the rectifying device is nested in the center of the bottom of the grid and is in a convex mirror structure, the inner wall of which is in a parabolic structure, the focal point of which is the same as the focal point of the parabolic structure of the inner wall of the air inlet, and the opening direction of the rectifying device is opposite to the opening direction of the air inlet; the rear end of the long tube is connected with the helicon wave thruster body, and the parallel fluid after rectification is sent into the helicon wave thruster. By nesting the rectifying device in a convex mirror structure in the bottom of the grid and making the focal points of the rectifying device and the air inlet coincide, the incoming airflow is refracted twice in succession and is guided into the rear long tube in a parallel direction, so that the particle impact corrosion and energy loss are effectively relieved, and the gas collection efficiency and the flow field stability are significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of aerospace propulsion technology, specifically relating to an air-breathing electric propulsion system for on-orbit propulsion of low-Earth orbit satellites. Background Technology

[0002] In the current aerospace field, air-breathing electric propulsion technology is an important development direction for the on-orbit propulsion of future low-Earth orbit satellites, and is widely used in many key mission scenarios such as continuous operation of ultra-low-Earth orbit satellites, space debris avoidance, and improvement of attitude and orbit control accuracy. However, at present, most air-breathing electric propulsion systems are still based on the core concept of single-stage air collection and single-stage refraction in structural design, and the overall scheme has obvious limitations in terms of propulsion efficiency and system life.

[0003] Traditional air-breathing electric propulsion systems typically consist of a grid, air intake, long tube, and electric propulsion device. These components are arranged along a fixed axis, with the air intake and propulsion structures relatively independent. Airflow direction is controlled by the geometry of the inner wall. They rely on a single refraction of the airflow to achieve focusing, guiding and compressing the incoming gas through the air intake wall, which then enters the long tube and undergoes ionization and acceleration. For example, some air-breathing propulsion platforms employ a parabolic air intake inner wall design, attempting to improve air collection efficiency through specular reflection. However, this design suffers from the following technical problems: unstable gas refraction: The single parabolic air intake structure focuses the airflow through a single refraction, and the direction of the airflow after refraction is not effectively controlled. A large number of particles enter the long tube non-parallel, impacting the inner wall and causing corrosion and velocity dissipation, affecting structural lifespan and system stability. Gas collection efficiency is easily degraded: Under ultra-low orbit conditions, the inlet wall is irradiated by atomic oxygen and high-energy particles, causing it to degenerate from specular reflection to diffuse reflection. This leads to an increase in particle scattering angle, making it impossible to focus the airflow and significantly reducing gas collection efficiency. Actual simulations show that when the wall reflection parameter δ increases from 0.2 to 1.0, the system's gas collection efficiency drops sharply from 71% to less than 12%. Thruster coupling is difficult: The non-directional airflow entering the long tube results in inconsistent flow velocity directions, causing unstable ionization efficiency of the ion source, accelerated electrode corrosion, and affecting the consistency of thrust distribution within the plasma source. This reduces the overall specific impulse and thruster life, hindering precise attitude and orbit control. Rectification mechanism is lacking: Mainstream systems only achieve primary focusing through a parabolic inlet wall, lacking a gas direction re-correction design. The lack of a "fixed-point focusing + parallel guidance" linkage rectification mechanism leads to unstable gas momentum distribution within the long tube, fluctuations in thrust output direction, and a tendency to cause attitude disturbances and attitude-orbit coupling instability. Summary of the Invention

[0004] The present invention aims to address the above-mentioned problems by providing an air-breathing electric propulsion system. By embedding a convex mirror-like rectifying device at the bottom of the grid and aligning it with the focal point of the air intake, the incoming gas is refracted twice and then guided parallel and directionally into the rear tube. This effectively mitigates particle impact corrosion, reduces energy loss, and significantly improves gas collection efficiency and flow field stability.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An air-breathing electric propulsion system includes a grid, an air inlet, a rectifier, and a spiral wave thruster body. The grid is the first device that contacts the incoming gas flow, and its bottom is connected to the front end of the air inlet. The inner wall of the air inlet has a parabolic structure, and its rear end is connected to a long tube. The rectifier is nested at the center of the bottom of the grid and has a convex mirror-like structure. Its inner wall has a parabolic structure, and its focal point is at the same position as the focal point of the parabolic structure on the inner wall of the air inlet. The opening direction of the rectifier is opposite to the opening direction of the air inlet. The rear end of the long tube is connected to the spiral wave thruster body, which delivers the rectified parallel fluid into the spiral wave thruster.

[0007] The air-breathing electric propulsion system is manufactured in an integrated 3D process (excluding the magnet wire and magnet in the helical wave thruster). The magnet wire is spirally wound around the outside of the helical wave thruster, and the magnet is placed on both sides of the helical wave thruster body.

[0008] The grid has a honeycomb structure, and the outer diameter of the grid is the same as the outer diameter of the circular inlet at the front end of the air intake.

[0009] The grille, air intake, rectifier, and long tube are arranged coaxially.

[0010] The grid is composed of 60-72 regular hexagons connected side by side, with an outer diameter of 122-130mm, an inner diameter of 112-120mm, and a thickness of 8-10mm.

[0011] The outer diameter of the circular inlet at the front end of the air intake is 122-130mm, the inner diameter is 112-120mm, and the thickness of the inner wall of the air intake is 1-2mm.

[0012] The focal point of the parabolic structure on the inner wall of the air intake is located 5 mm from the rear end of the grille and 30-40 mm from the front end of the long tube.

[0013] The tube is 20mm long and 20mm in diameter.

[0014] The rectifier has an inner diameter of 8-9 mm, an outer diameter of 10-11 mm, and a height of 4-5 mm.

[0015] The grid injects incoming air into the air intake at a speed of 7900 m / s.

[0016] The spiral wave propeller is powered by energizing the magnet wires through the bolts connecting the wires.

[0017] The rear end of the connecting spiral wave thruster is connected to an external expansion nozzle, which makes the airflow ejected more evenly.

[0018] The grille, air intake, long pipe, and rectifier are all made of metal.

[0019] The rectifier is made of a corrosion-resistant specular reflective material.

[0020] The beneficial effects of this invention are as follows:

[0021] To create parallel airflow and improve airflow directionality and gas collection efficiency: This invention proposes the combined use of a parabolic air inlet and a convex mirror-like rectifying device. Both structures have parabolic inner walls with overlapping focal points, allowing the incoming gas to undergo two precise refractions within the system, thus guiding the parallel jet into the long tube. The rectifying device is an axisymmetric convex mirror-like structure with its opening direction opposite to that of the air inlet, forming a refraction "reflection-rectification" structure that effectively reduces particle deflection angle and rebound, improving airflow directionality and gas collection efficiency.

[0022] Supports functional upgrades: The rectifier coincides with the inlet focal point, providing excellent parameter adjustability. Depending on mission changes, rectifier components with different outlet inner diameters, reflection angles, or focal point positions can be replaced to achieve targeted upgrades in flow alignment accuracy or collection efficiency.

[0023] Enhanced design flexibility: When facing different orbital altitudes, atomic oxygen densities, or thrust requirements, different specifications of grids, rectifiers, or long tubes can be flexibly selected to construct an air intake system that meets specific application needs, with good mission versatility and structural expandability.

[0024] All components have undergone material corrosion resistance and flow field stability tests in a ground-based atomic oxygen simulation environment to ensure the structural stability and performance reliability of the system during long-term orbital operation. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the air-breathing electric propulsion system of the present invention;

[0026] Among them, 1 is the grid; 2 is the air intake; 3 is the long pipe; 4 is the rectifier; 5 is the spiral wave thruster; and 6 is the outward expansion nozzle. Detailed Implementation

[0027] Example 1

[0028] like Figure 1As shown, an air-breathing electric propulsion system includes a honeycomb grid 1, an air intake 2, a rectifier 4, and a spiral wave thruster 5. The grid is the first device that comes into contact with the incoming gas, and its bottom is connected to the front end of the air intake 2. The inner wall of the air intake 2 has a parabolic structure, and its rear end is connected to a long tube 3. The rectifier 4 is nested in the center of the bottom of the grid 1 and has a convex mirror-like structure. Its inner wall has a parabolic structure, and its focal point is at the same position as the focal point of the parabolic structure on the inner wall of the air intake. The opening direction of the rectifier is opposite to the opening direction of the air intake. The rear end of the long tube 3 is connected to the spiral wave thruster 5, which sends the rectified parallel fluid into the spiral wave thruster 5.

[0029] The air-breathing electric propulsion system is manufactured in 3D as a single unit, with magnetic wire spirally wound around the outside of the spiral wave propulsion unit 5 body, and the magnets are placed on both sides of the spiral wave propulsion unit 5 body.

[0030] The outer diameter of the grid 1 is the same as the outer diameter of the circular inlet at the front end of the intake duct 2.

[0031] The grid 1, air intake 2, rectifier 4, and long tube 3 are arranged coaxially.

[0032] The grid 1 is composed of 60-72 regular hexagons connected side by side, with an outer diameter of 122-130 mm, an inner diameter of 112-120 mm, and a grid thickness of 8-10 mm. The hexagonal honeycomb grid structure can improve the consistency of the air intake direction and block the backflow of some particles reflected from the inner wall, thereby improving the overall air collection efficiency and fluid stability of the system.

[0033] The outer diameter of the circular inlet at the front end of the air intake duct 2 is 122-130mm, the inner diameter is 112-120mm, and the thickness of the inner wall of the air intake duct is 1-2mm.

[0034] The focal point of the parabolic structure on the inner wall of the air intake duct 2 is located 5 mm from the rear end of the grid and 30-40 mm from the front end of the long tube.

[0035] The length of the long tube 3 is 20mm and the diameter is 20mm.

[0036] The rectifier 4 has an inner diameter of 8-9 mm, an outer diameter of 10-11 mm, and a height of 4-5 mm.

[0037] The grid 1 injects incoming air into the air intake duct 2 at a speed of 7900 m / s.

[0038] The spiral wave propeller is powered by energizing the magnet wires through the bolts connecting the wires.

[0039] The rear end of the connecting spiral wave thruster 5 is connected to the expansion nozzle, so that the airflow is ejected more evenly.

[0040] The grille 1, air intake 2, long pipe 3, and rectifier 4 are all made of metal material, namely stainless steel.

[0041] The rectifier 4 is made of a corrosion-resistant mirror-reflective material, which is stainless steel that has been finely polished.

[0042] After the entire unit is integrated, corrosion adaptability is verified in an atomic oxygen simulation chamber; the intake path is visualized and analyzed through a wind tunnel or simulated incoming flow system; laser particle image velocimetry (PIV) is used to test whether the airflow after the rectifier is parallel, and parameters such as collection efficiency and streamline stability are recorded, and the system performance is verified to meet the design specifications.

[0043] Corrosion adaptability test conditions and procedures:

[0044] After the entire unit was integrated, its corrosion adaptability was verified in an atomic oxygen simulation chamber. The test conditions were as follows:

[0045] 1. Simulation chamber environmental parameters: Atomic oxygen concentration is approximately 5 × 10⁻⁶. 15 atoms / cm 3 The temperature is controlled between 0-50℃, and the airflow speed simulates the orbital speed, which is approximately 7800m / s;

[0046] 2. Exposure duration: 120 hours of continuous operation to simulate the cumulative corrosion dose of the track over 2 years;

[0047] 3. Testing equipment: High-vacuum atomic oxygen simulation device, equipped with corrosion resistance monitoring system and surface composition detection system;

[0048] 4. Test steps:

[0049] (1) The entire propulsion system was sealed and installed in the simulation cabin;

[0050] (2) Activate the atomic oxygen source and adjust it to the set dose;

[0051] (3) Real-time acquisition of data on structural surface loss, weight change, and reflectivity change;

[0052] (4) Take photos and perform spectral analysis of the changes in the main structural reflectance characteristics every 24 hours;

[0053] (5) After the test is completed, check the corrosion of the rectifier and the inner wall of the intake duct to determine the stability of the material;

[0054] Results evaluation: The average corrosion rate of the rectifier mirror layer is less than 0.05 μm / h, which is below the design limit; the structural integrity and reflection performance remain good, meeting the requirements for long-term service.

[0055] Airflow rectification test (wind tunnel + PIV visualization):

[0056] 1. Testing platform: High-speed, low-pressure, controllable flow wind tunnel;

[0057] 2. Test objective: To verify whether the rectified airflow is parallel and whether the flow field is stable;

[0058] 3. PIV Test Settings:

[0059] (1) Laser sheet thickness: 1mm;

[0060] (2) Particle type: atomized TiO2 particles, particle size <1μm;

[0061] (3) Shooting frequency: 500Hz;

[0062] (4) Flow rate setting: The simulated inflow velocity is 7900 m / s;

[0063] 4. Steps:

[0064] (1) Install the propulsion system onto the wind tunnel test frame and stabilize and adjust its attitude;

[0065] (2) Turn on the incoming flow system and adjust it to the target speed;

[0066] (3) The laser sheet scans the airflow area at the rear end of the rectifier;

[0067] (4) Acquire multiple frames of PIV images for velocity field calculation and visualization;

[0068] (5) Extract streamline diagrams, velocity vector diagrams, and vorticity fields to analyze whether parallel directional flow is formed;

[0069] 5. Test Results:

[0070] (1) The average deflection angle of the flow field after rectification is less than 2°, and the maximum velocity disturbance range does not exceed ±5%;

[0071] (2) The collection efficiency reaches 73%, and the streamline distribution shows a quasi-parallel trend;

[0072] (3) It meets the design goal of "focus + parallel guidance" and the system performance meets the requirements.

[0073] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An air-breathing electric propulsion system, characterized in that: The system includes a grid (1), an air intake (2), a rectifier (4), and a spiral wave thruster (5) body. The bottom of the grid (1) is connected to the front end of the air intake. The inner wall of the air intake (2) is a parabolic structure, and the rear end of the air intake (2) is connected to a long tube (3). The rectifier (4) is nested in the center of the bottom of the grid (1). It is a convex mirror structure with a parabolic inner wall. Its focal point is the same as the focal point of the parabolic structure on the inner wall of the air intake (2). The opening of the rectifier (4) faces the opposite direction to the opening of the air intake (2). After being refracted twice, the incoming gas is guided parallel and directionally into the rear long tube (3). The rear end of the long tube (3) is connected to the spiral wave thruster (5) body, which sends the rectified parallel fluid into the spiral wave thruster (5). The grid (1), air intake (2), rectifier (4), and long tube (3) are coaxially arranged. The air-breathing electric propulsion system is integrally 3D manufactured.

2. The air-breathing electric propulsion system as described in claim 1, characterized in that: The magnet wire is spirally wound around the outside of the body of the spiral wave thruster (5), and the magnet is placed on both sides of the body of the spiral wave thruster (5).

3. The air-breathing electric propulsion system as described in claim 1, characterized in that: The grid (1) is a honeycomb structure, and the outer diameter of the grid (1) is the same as the outer diameter of the circular inlet at the front end of the air intake (2).

4. The air-breathing electric propulsion system as described in claim 1, characterized in that: The grid (1) is composed of 60-72 regular hexagons with their sides connected together. The outer diameter is 122-130mm, the inner diameter is 112-120mm, and the thickness of the grid is 8-10mm.

5. The air-breathing electric propulsion system as described in claim 1, characterized in that: The outer diameter of the circular inlet at the front end of the air intake (2) is 122-130mm, the inner diameter is 112-120mm, and the thickness of the inner wall of the air intake (2) is 1-2mm.

6. The air-breathing electric propulsion system as described in claim 1, characterized in that: The focal point of the parabolic structure on the inner wall of the air intake (2) is 5 mm from the rear end of the grid (1) and 30-40 mm from the front end of the long tube (3).

7. The air-breathing electric propulsion system as described in claim 1, characterized in that: The rectifier (4) has an inner diameter of 8-9 mm, an outer diameter of 10-11 mm, and a height of 4-5 mm.

8. The air-breathing electric propulsion system as described in claim 1, characterized in that: The rear end of the spiral wave thruster (5) is connected to the expansion nozzle (6) to make the airflow spray out more evenly.

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