Spacecraft orbit vacuum degree in-situ measuring device

Abstract

The invention relates to a spacecraft orbit vacuum degree in-situ measurement device, a conversion module comprises a module main body and a diffusion grid plate with a plurality of diffusion holes, the interior of the module main body is a cavity, the diffusion grid plate is arranged in the cavity of the module main body, the side surface of the module main body is provided with an air inlet hole plate corresponding to the diffusion grid plate, and the module main body is provided with an air outlet hole; a plurality of vertical air inlet holes are formed in the air inlet hole plate; the diffusion grid plate is used for enabling the high-speed oriented molecular flow gas to enter the conversion module and then be converted into equilibrium-state gas through no less than one time of collision; one end of the detection module is communicated with the conversion module through a fixed flow guide small hole element, and the other end of the detection module is connected with the low-temperature pump through a pneumatic gate valve; and a vacuum measurement module is arranged in the detection module. According to the invention, the influence of a high-speed directional flow field on equilibrium state gas in a detection chamber can be reduced, the collision probability of the high-speed directional molecular flow entering the conversion module is increased, the equilibrium state conversion degree of the high-speed directional molecular flow is improved, and the pressure measurement precision and the measurement range are relatively high.

Description

Technical Field

[0001] The invention relates to the field of vacuum measurement technology, and in particular to an in-situ measurement device for the vacuum degree of a spacecraft orbit. Background Art

[0002] When a spacecraft is in orbit, in-situ measurement of the surface vacuum is crucial for precise attitude and orbit control of the spacecraft. Moreover, with the development of aerospace technology, the research and development of lightweight, low-power miniaturized vacuum measuring instruments has become a new research hotspot. In addition, the vacuum degree of the spacecraft operating environment is high, the mean free path of gas molecules is large, and most spacecraft operate at extremely high speeds (usually close to the first cosmic speed of 7.9 km / s). Therefore, the gas molecules around the spacecraft present a high-speed directional molecular flow state relative to the spacecraft, with characteristics such as anisotropy and unidirectional velocity.

[0003] Unlike the equilibrium gas in the Earth's atmosphere, the high-speed directional molecular flow around the spacecraft during operation is essentially a non-equilibrium gas, which does not satisfy the ideal gas law in equilibrium, such as Maxwell's gas distribution law, and therefore cannot be measured in situ using a conventional vacuum gauge. At present, the most commonly used instrument for in-situ measurement of the vacuum degree of a spacecraft during orbital operation is a conversion module type direction gauge, whose main structure includes two parts: a conversion module and a detection module. The basic principle of measuring the vacuum degree of a directional molecular flow is: the directional flow gas enters the conversion module and is converted into an equilibrium gas, and the equilibrium gas enters the detection chamber, and the equilibrium gas is measured by the detection module. Therefore, the role of the conversion module of the direction gauge plays a key role in the accurate measurement of non-equilibrium gas. Represented by open double-cone direction gauges, small hole inlet conversion module direction gauges, and single-tube inlet conversion module direction gauges, direction gauges have been widely used in the fields of high-altitude atmospheric density measurement, space station leak detection, lunar surface vacuum measurement, and deep space exploration.

[0004] Existing direction gauges mostly use a structure where the gas flow is coaxial with the direction gauge. The disadvantage of this structure is that for high-speed directional flow gas, the flow field in the detection chamber will be affected, and the equilibrium state of the gas in the detection chamber cannot be guaranteed, resulting in large measurement errors. In addition, the detection module of the direction gauge is mostly a BA gauge, which can only measure less than 10 -1 The vacuum degree of Pa has a lower upper limit of measurement. Summary of the invention

[0005] In order to solve the technical problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an in-situ measurement device for the spacecraft orbit vacuum degree, which improves the degree of equilibrium state transformation of high-speed directional molecular flow in space, improves the measurement accuracy, and solves the problem that it is difficult to perform in-situ accurate measurement of the surface vacuum degree of a spacecraft when it is in orbit.

[0006] To achieve the above-mentioned invention object, the technical solution of the present invention is: an in-situ measurement device for spacecraft orbit vacuum degree, comprising a conversion module and a detection module;

[0007] The conversion module comprises a module body and a diffuser grid with a plurality of diffuser holes, the interior of the module body is a cavity, the diffuser grid is arranged in the cavity of the module body, and an air inlet plate corresponding to the diffuser grid is arranged on the side of the module body, and the air inlet plate is provided with a plurality of vertical air inlet holes;

[0008] The diffuser grid is used to convert the high-speed directional molecular flow gas into equilibrium gas after entering the conversion module through at least one collision;

[0009] One end of the detection module is connected to the conversion module through a fixed flow conductance orifice element, and the other end is connected to the cryogenic pump through a pneumatic gate valve;

[0010] A vacuum measurement module is arranged in the detection module.

[0011] According to a technical solution of the present invention, the module body is spherical in structure, and the normal line of the air inlet plate is perpendicular to the axis of the module body;

[0012] The air inlet plate is circular, and the diameter R1 of the air inlet plate and the inner diameter R2 of the module body satisfy the following relationship:

[0013] 0.2≤R1 / R2≤0.4.

[0014] According to a technical solution of the present invention, the diffuser grid plate and the air inlet plate are installed coaxially.

[0015] According to a technical solution of the present invention, the vacuum measurement module is a composite vacuum measurement module, including a capacitive film gauge and a BA gauge.

[0016] According to a technical solution of the present invention, a positive voltage is applied to the air inlet plate, and the voltage is 10V to 50V.

[0017] According to a technical solution of the present invention, the diffuser grid is in a conical, multi-stage conical or spherical shape.

[0018] According to a technical solution of the present invention, the cone angle of the conical or multi-conical diffuser grid plate is 60° to 90°, and the normal angle between two adjacent diffuser holes on the diffuser plate is 30°.

[0019] According to a technical solution of the present invention, the vertical air inlet holes and the diffuser holes are both circular holes with the same size, and the diameter is 2 mm to 3 mm.

[0020] According to a technical solution of the present invention, the module body is made of 316L stainless steel.

[0021] According to a technical solution of the present invention, the measurement range is 5×10 -8 Pa~1×10 2 Pa.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] In the in-situ measurement device for the vacuum degree of a spacecraft orbit of the present invention, the conversion module first receives the high-speed directional molecular flow gas, and converts the non-equilibrium high-speed directional molecular flow into equilibrium gas through its internal structure, and then transmits it to the detection module for measurement. The detection module accurately obtains the pressure information of the equilibrium gas through its internal detection device, thereby realizing the in-situ measurement of the vacuum degree of the spacecraft orbit. The measuring device of the present invention solves the problem that it is difficult to accurately measure the surface vacuum degree of a spacecraft in situ when it is in orbit, and has a clear structure, clear functional division of labor, is easy to manufacture, install and maintain, and has high reliability and stability.

[0024] The present invention can reduce the influence of the high-speed directional flow field on the equilibrium gas in the detection chamber. A diffuser grid is arranged in the conversion module to increase the collision probability of the high-speed directional molecular flow after entering the conversion module, thereby improving the conversion module's equilibrium state conversion degree of the high-speed directional molecular flow and improving the measurement accuracy.

[0025] In the present invention, an orifice plate connected to a positive voltage is arranged at the entrance, which can effectively prevent ions in the space from entering the conversion chamber, thereby ensuring that neutral particles are measured.

[0026] In the present invention, the detection module in the detection chamber adopts a composite structure of a BA gauge and a capacitance film gauge, thereby broadening the pressure measurement range. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A schematic diagram schematically shows the structure of an in-situ measurement device for the spacecraft orbit vacuum degree in an embodiment of the present invention;

[0029] Figure 2 (ac) schematically show the structure of the diffuser grid plate in the embodiment of the present invention;

[0030] Figure 3 The structural diagram of the air inlet plate in the embodiment of the present invention is schematically shown.

[0031] in, Figures 1 to 3 The corresponding relationship between the reference numerals and the component names is as follows:

[0032] 1. Air inlet plate; 2. Conversion module; 3. Diffuser grid plate; 4. Fixed flow conductance hole; 5. Detection module; 6. Capacitor film gauge; 7. BA gauge; 8. Wiring terminal; 9. Pneumatic plug valve; 10. Cryogenic pump. DETAILED DESCRIPTION

[0033] The description of the embodiments of this specification should be combined with the corresponding drawings, which should be considered as part of the complete specification. In the drawings, the shape or thickness of the embodiments may be enlarged and indicated for simplification or convenience. Furthermore, the parts of each structure in the drawings will be described separately. It is worth noting that the elements not shown in the drawings or not described in words are in a form known to ordinary technicians in the relevant technical field.

[0034] The description of the embodiments herein and any reference to directions and orientations are only for the convenience of description and are not to be construed as any limitation on the scope of protection of the present invention. The following description of the preferred embodiments may involve combinations of features, which may exist independently or in combination, and the present invention is not particularly limited to the preferred embodiments. The scope of the present invention is defined by the claims.

[0035] like Figures 1 to 3 As shown, based on the conversion module type direction gauge, the present invention proposes an in-situ measurement device for spacecraft orbit vacuum, including a conversion module 2 and a detection module 5.

[0036] The conversion module 1 and the detection module 2 work together to form a complete measuring device system. In the process of measuring the spacecraft orbit vacuum, the conversion module 1 first receives the high-speed directional molecular flow gas, converts the non-equilibrium high-speed directional molecular flow into equilibrium gas through its internal structure, and then transports it to the detection module 2 for measurement. The detection module 2 accurately obtains the pressure information of the equilibrium gas through its internal detection device, thereby realizing the in-situ measurement of the spacecraft orbit vacuum. The measuring device of the present invention has a clear structure and clear functional division of labor, is easy to manufacture, install and maintain, and improves the reliability and stability of the entire measuring device.

[0037] The conversion module 2 includes a module body and a diffuser grid plate 3 with a plurality of diffuser holes. The interior of the module body is a cavity. The diffuser grid plate 3 is arranged in the cavity of the module body. An air inlet plate 1 corresponding to the diffuser grid plate 3 is arranged on the side of the module body. The air inlet plate is provided with a plurality of vertical air inlet holes. The diffuser grid plate 3 is arranged corresponding to the air inlet plate 1, which can reduce the influence of the high-speed directional flow field on the equilibrium gas in the detection chamber. The diffuser grid plate 3 can increase the collision probability of the high-speed directional molecular flow after entering the conversion module, thereby improving the conversion degree of the conversion module to the equilibrium state of the high-speed directional molecular flow and improving the measurement accuracy.

[0038] The diffuser grid 3 is used to convert the high-speed directional molecular flow gas into equilibrium gas after entering the conversion module through at least one collision;

[0039] The detection module 5 is a columnar structure, one end of which is connected to the conversion module 2 through a fixed flow conductance orifice element 4, and the other end is connected to the cryogenic pump 10 through a pneumatic gate valve 9;

[0040] A vacuum measurement module is arranged in the detection module 5 .

[0041] During the spacecraft orbit vacuum measurement process, the conversion module 2 first contacts the high-speed directional molecular flow gas, the diffuser grid plate 3 is set in the cavity of the module body, and the air inlet plate 1 is located on the side of the module body and has a vertical air inlet, so that the gas can smoothly enter the conversion module 2. The detection module 5 is connected to the conversion module 2 through the fixed flow guide orifice element 4, ensuring the gas transmission path, and the other end is connected to the cryogenic pump 10 and the pneumatic plug valve 9, which can maintain the vacuum environment and gas flow stability in the detection module 5. The vacuum measurement module in the detection module 5 is responsible for the final measurement work, realizing the complete process from gas collection to measurement, ensuring the accuracy and reliability of the measurement, and solving the problem of difficulty in in-situ accurate measurement of the surface vacuum of the spacecraft when it is in orbit.

[0042] In some embodiments of the present invention, the module body is spherical in structure, and the normal line of the air inlet plate 1 is perpendicular to the axis of the module body;

[0043] The air inlet plate 1 is circular, and the diameter R1 of the air inlet plate 1 and the inner diameter R2 of the module body satisfy the following relationship:

[0044] 0.2≤R1 / R2≤0.4.

[0045] The module body is spherical in structure and the normal of the air inlet plate 1 is perpendicular to the axis of the module body. When the high-speed directional molecular flow rushes towards the measuring device, the influence of the high-speed directional flow field on the equilibrium gas in the detection chamber can be reduced. Compared with the traditional coaxial structure direction gauge, the vertical air inlet plate 1 prevents the gas from directly impacting the detection module 5, reducing the direct interference with the internal flow field of the detection module 5. After entering the conversion module 2, the gas has more opportunities to disperse and buffer in the module body, increasing the collision probability of gas molecules in the conversion module 2. At the same time, the diameter R1 of the air inlet plate 1 and the inner diameter R2 of the module body meet the relationship of 0.2≤R1 / R2≤0.4, ensuring the appropriate gas entry amount and speed, thereby ensuring that the gas can enter the converter module in a relatively collimated state and flux, ensuring the directionality and accuracy of the measurement. If R1 / R2 is too large, the instantaneous influx of a large amount of high-speed gas may cause the gas to enter the detection module 5 without sufficient collision in the module; if it is too small, the gas entry amount is insufficient.

[0046] In some embodiments of the present invention, the diffuser grid plate 3 is coaxially installed with the air inlet hole plate 1 .

[0047] The diffuser grid 3 is coaxially installed with the air inlet orifice plate 1, so that the high-speed directional molecular flow gas can collide with the diffuser grid 3 in an orderly manner along the axial direction after passing through the air inlet orifice plate 1 and entering the conversion module 2. Under the blocking and guidance of the diffuser grid 3, the gas molecules collide multiple times along the predetermined path, ensuring that the gas can be more efficiently converted into equilibrium gas. If the diffuser grid 3 is not coaxial with the air inlet orifice plate 1, the movement trajectory of the gas molecules after entering the conversion module 2 will become chaotic, and some gases may not fully collide with the diffuser grid 3 and directly enter the detection module 5, reducing the degree of equilibrium conversion, thereby affecting the measurement accuracy.

[0048] In some embodiments of the present invention, the vacuum measurement module is a composite vacuum measurement module, including a capacitive film gauge 6 and a BA gauge 7 .

[0049] Capacitor film gauge 6 has high accuracy (measurement range is 1.3×10 2 Pa-1.3×10-1Pa, with an accuracy of 0.2% FS), which can accurately measure gas pressure in a relatively high pressure range. BA Rule 7 is suitable for measuring lower pressure ranges (1.3×10-1Pa-5×10Pa, with an accuracy of 20% FS). The combination of the two forms a composite vacuum measurement module, which broadens the pressure measurement range of the entire measuring device, enabling it to adapt to the measurement needs of different vacuum levels in the spacecraft orbit environment, and can effectively measure from the higher pressure low-Earth orbit environment to the extremely low pressure deep space exploration environment, providing accurate vacuum data support for tasks such as precise attitude and orbit control of spacecraft.

[0050] The capacitor film gauge 6 and the BA gauge 7 realize signal input, signal output and power supply through the connection terminal 8.

[0051] In some embodiments of the present invention, a positive voltage is applied to the air inlet plate 1, and the voltage is 10V to 50V.

[0052] There are various ions in the spacecraft operating environment. When a positive voltage is applied to the air inlet plate 1, an electric field will be formed around the air inlet. When ions approach the air inlet, they will be deviated from the air inlet by the electric field force, thereby effectively preventing ions in space from entering the conversion module 2. It is ensured that only neutral particles enter the conversion module 2, avoiding the interference of ions on the measurement results, ensuring that the pressure of pure neutral gas molecules is measured, and improving the accuracy and reliability of the measurement.

[0053] like Figure 2 As shown, in some embodiments of the present invention, the diffuser grid plate 3 is in the shape of a cone, a multi-stage cone or a spherical shape, wherein: Figure 2 (a) shows a spherical diffuser grid; Figure 2 (b) shows a conical diffuser grid; Figure 2 (c) shows a multi-stage conical diffuser grid;

[0054] The cone angle of the conical or multi-conical diffuser grid 3 is 60° to 90°, and the normal angle between two adjacent diffuser holes on the diffuser plate is 30°. Under this angle, gas molecules can obtain more suitable turning and collision opportunities when passing through the diffuser holes, so that the energy exchange and equilibrium state transformation of the gas in the conversion module 2 are more sufficient, thereby improving the processing capability and measurement accuracy of the measuring device for high-speed directional molecular flow.

[0055] In some embodiments of the present invention, the vertical air inlet and the diffuser are both circular holes with the same size, 2 mm to 3 mm in diameter, which ensures the smooth flow of gas molecules through the air inlet and diffuser holes, and reduces the resistance and turbulence of gas flow. At the same time, the size is larger than the mean free path of the gas molecules, so that the gas molecules can collide and mix effectively in the hole and the module, further improving the equilibrium conversion efficiency and ensuring the accuracy of the measurement.

[0056] In some embodiments of the present invention, the module body is made of 316L stainless steel, which has good mechanical properties and corrosion resistance, can maintain the stability of the structure, and prevent the performance of the measuring device from being affected by material deformation or corrosion. At the same time, its good strength and toughness can withstand the vibration and impact during the launch and operation of the spacecraft, ensure the normal operation of the measuring device, improve the service life and reliability of the device, and reduce maintenance costs.

[0057] In some embodiments of the present invention, the measurement range is 5×10 -8 Pa~1×10 2 Pa.

[0058] During the operation of the spacecraft, the high-speed directional molecular flow moving relative to it enters the conversion module 2 through the air inlet plate 1, and forms a stable equilibrium pressure inside the detection module 5 after colliding with the diffuser grid plate 3 and the inner wall of the conversion module 2. There is a quantitative relationship between this pressure and the pressure of the high-speed directional molecular flow, so the pressure measured by the detection module 5 can be converted to the pressure of the high-speed directional molecular flow. Assuming that the speed of the spacecraft during normal operation is 8km / s, the diameter of the equivalent air inlet of the air inlet plate is about 2cm, so it can be calculated that the volume entering the conversion module per unit time is about 2m 3 / s, so in order to maintain a good ultimate vacuum degree inside the detection module, the pumping speed can be selected to be (1~2)m 3 / s cryopump 10.

[0059] The above is an explanation of the implementation mode of the present application by specific specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Although the description of the present application will be introduced in conjunction with some embodiments, this does not mean that the features of this application are limited to the implementation mode. On the contrary, the purpose of introducing the application in conjunction with the implementation mode is to cover other options or modifications that may be extended based on the claims of the present application. The present application can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present application, some specific details are omitted in the description. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0060] In the description of the present application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "outside", "inside", "circumferential", "radial", "axial" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0061] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "setting", "installation", "connection" and "fitting" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0062] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A spacecraft orbit vacuum in-situ measurement device, characterized in that: It comprises a conversion module (2) and a detection module (5); The conversion module (2) comprises a module body and a diffuser grid plate (3) with a plurality of diffuser holes, the interior of the module body is a cavity, the diffuser grid plate (3) is arranged in the cavity of the module body, and an air inlet plate (1) corresponding to the diffuser grid plate (3) is arranged on the side of the module body, and the air inlet plate is provided with a plurality of vertical air inlet holes; The diffuser grid (3) is used to convert the high-speed directional molecular flow gas into equilibrium gas after it enters the conversion module through at least one collision; One end of the detection module (5) is connected to the conversion module (2) via a fixed flow conductance orifice element (4), and the other end is connected to the cryogenic pump (10) via a pneumatic gate valve (9); A vacuum measurement module is arranged in the detection module (5).

2. The spacecraft orbit vacuum in-situ measurement device according to claim 1, characterized in that: The module body is in a spherical structure, and the normal line of the air inlet plate (1) is perpendicular to the axis of the module body; The air inlet plate (1) is circular, and the diameter R1 of the air inlet plate (1) and the inner diameter R2 of the module body satisfy the following relationship: 0.2≤R1 / R2≤0.

4.

3. The spacecraft orbit vacuum in-situ measurement device according to claim 1, characterized in that: The diffuser grid plate (3) is coaxially mounted with the air inlet hole plate (1).

4. The spacecraft orbit vacuum in-situ measurement device according to claim 1, characterized in that: The vacuum measurement module is a composite vacuum measurement module, comprising a capacitance film gauge (6) and a BA gauge (7).

5. The spacecraft orbit vacuum in-situ measurement device according to claim 4, characterized in that: A positive voltage is applied to the air inlet plate (1), and the voltage is in the range of 10V to 50V.

6. The spacecraft orbit vacuum in-situ measurement device according to claim 1, characterized in that: The diffuser grid plate (3) is in the shape of a cone, a multi-stage cone or a spherical surface.

7. The spacecraft orbit vacuum in-situ measurement device according to claim 6, characterized in that: The cone angle of the conical or multi-conical diffuser grid plate (3) is 60° to 90°, and the normal angle between two adjacent diffuser holes on the diffuser plate is 30°.

8. The spacecraft orbit vacuum in-situ measurement device according to claim 1, characterized in that: The vertical air inlet holes and the diffuser holes are both circular holes with the same size, and the diameter is 2 mm to 3 mm.

9. The spacecraft orbit vacuum in-situ measurement device according to claim 1, characterized in that: The module body is made of 316L stainless steel.

10. The spacecraft orbit vacuum in-situ measurement device according to claim 1, characterized in that: The measuring range is 5×10 -8 Pa~1×10 2 Pa.

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