Large-current wide-adjustment hollow cathode top hole size determination method, system, medium and equipment

Abstract

The invention provides a method, a system, a medium and equipment for determining the size of a top hole of a large-current wide-adjustment hollow cathode, and belongs to the technical field of aerospace propulsion, a mathematical relationship is established for the ratio of the diameter to the length of the top hole of the cathode, and the method comprises the following steps: S1, determining the working current range of the hollow cathode; s2, calculating an optimal cathode top hole diameter D1 corresponding to the minimum current working point Il; s3, calculating an optimal cathode top hole diameter Dh corresponding to the maximum current working point Ih; and S4, determining the optimal cathode top hole diameter Dc and the optimal cathode top hole length Lc according to a correlation formula of the optimal cathode top hole diameter D1 corresponding to the minimum current working point Il, the optimal cathode top hole diameter Dh corresponding to the maximum current working point Ih, the optimal cathode top hole diameter Dc and the optimal cathode top hole length Lc. According to the invention, a design basis can be provided for performance optimization of the large-current wide-adjustment hollow cathode.

Description

Technical Field

[0001] The present invention relates to the field of aerospace propulsion technology, and in particular to a method, system, medium and equipment for determining the size of a large-current wide-adjustable hollow cathode top hole. Background Art

[0002] A hollow cathode is a discharge device that uses thermionic emission technology to provide an electron beam and is often used as an igniter or neutralizer for Hall or ion propulsion. Hollow cathodes with high current (>100A) and wide turndown ratios are widely used in high-power electric propulsion, especially for multi-mode missions, and are currently one of the key research areas in high-power electric propulsion. However, under current technological conditions, high-current, wide-turndown ratio hollow cathodes are unable to maintain a high-performance operating mode (point-like) across all current operating points, resulting in a major bottleneck in the engineering development of such hollow cathodes. This is one of the major issues that researchers urgently need to address.

[0003] Regarding the design method of hollow cathodes, researchers mainly focus on the size and structural design of the cathode top: the public document "Matthew T D. An Evaluation of Hollow Cathode Scaling to Very Low Power and Flow Rate. IEPC-97-189." provides design formulas for the cathode top diameter and emitter cavity diameter in relation to the discharge current; the public document "Matthew T D. Evaluation of Low-Current Orificed Hollow Cathodes. PhD thesis. University of Michigan, 1999" proposes that for low-current hollow cathodes, the cathode top length [mm] should be 1 / 6 of the discharge current, and the emission area of ​​the reflector should be consistent with the design area corresponding to the Charleson emission current; the public document "Hani K. Development and Testing of High Current Hollow Cathodes for High Power Hall Thrusters. AIAA-2012-4080" proposes that for 100A-class hollow cathodes, the cathode top aperture size should be appropriately increased, which will reduce the emitter temperature and improve the cathode performance; the public document "Kubota K. Numerical and "Experimental Study on Discharge Characteristics of High-Current Hollow Cathode. AIAA-2016-4628" proposed that for high-current cathodes (180A class), the cathode top aperture does not have a significant impact on performance as the cathode top-contact distance. It also revealed for the first time that high-current hollow cathodes have an electron bunching effect, which can degrade discharge performance.

[0004] Patent document CN106373842A (application number: 201610959108.2) discloses a method for widening the discharge current range of a hollow cathode point mode, which relates to the technical field of widening the discharge current range of a hollow cathode. To address the narrow discharge current range of the hollow cathode point mode, the traditional method of widening the discharge current range of the hollow cathode point mode reduces the specific impulse of the entire propulsion system and easily causes cathode overheating. The cathode components are designed according to the actual needs of the hollow cathode, and the throttle orifice inward displacement distance is preliminarily set; the cathode is allowed to operate normally, and the hollow cathode operating parameters are measured; the throttle orifice inward displacement distance is optimized based on the hollow cathode operating parameters, and then the cathode is allowed to operate normally, and the hollow cathode operating parameters are measured; step three is repeated until the optimal throttle orifice inward displacement distance is found.

[0005] In summary, there are relatively detailed design methods and design strategy studies for hollow cathodes with small or large currents. However, these design methods cannot solve the problem of "all operating points cannot be maintained in a point-like mode" for large current hollow cathodes with a wide adjustment ratio. Therefore, it is necessary to establish a new design method for large current wide adjustment hollow cathodes to solve this problem. Summary of the Invention

[0006] In view of the defects in the prior art, the purpose of the present invention is to provide a method, system, medium and equipment for determining the size of the top hole of a large current wide adjustment hollow cathode.

[0007] According to the present invention, a method for determining the top hole size of a large current wide adjustment hollow cathode is provided, comprising:

[0008] Step S1: determining the operating current range of the hollow cathode;

[0009] Step S2: Calculate the minimum current operating point I l The corresponding optimal cathode top hole diameter D l ;

[0010] Step S3: Calculate the maximum current operating point I h The corresponding optimal cathode top hole diameter D h ;

[0011] Step S4: According to the minimum current operating point I l The corresponding optimal cathode top hole diameter D l , Maximum current operating point I h The corresponding optimal cathode top hole diameter D h , optimal cathode top hole diameter D c and length L c The optimal cathode top hole diameter D is determined by the correlation formula c and length L c .

[0012] Preferably, step S2 includes:

[0013]

[0014] Preferably, step S3 includes:

[0015]

[0016] Preferably, the step S4 includes:

[0017]

[0018] According to the present invention, a large current wide adjustment hollow cathode top hole size determination system is provided, comprising:

[0019] Module M1: Determine the operating current range of the hollow cathode;

[0020] Module M2: Calculate the minimum current operating point I l The corresponding optimal cathode top hole diameter D l ;

[0021] Module M3: Calculate the maximum current operating point I h The corresponding optimal cathode top hole diameter D h ;

[0022] Module M4: According to the minimum current operating point I l The corresponding optimal cathode top hole diameter D l , Maximum current operating point I h The corresponding optimal cathode top hole diameter D h , optimal cathode top hole diameter D c and length L c The optimal cathode top hole diameter D is determined by the correlation formula c and length L c .

[0023] Preferably, the module M2 includes:

[0024]

[0025] Preferably, the module M3 includes:

[0026]

[0027] Preferably, the module M4 includes:

[0028]

[0029] According to an electronic device provided by the present invention, the electronic device includes a memory and at least one processor, wherein instructions are stored in the memory;

[0030] The at least one processor calls the instructions in the memory to enable the electronic device to execute the various steps of the method for determining the top hole size of a large current wide-adjustable hollow cathode as described above.

[0031] According to a computer-readable storage medium provided by the present invention, instructions are stored on the computer-readable storage medium, and when the instructions are executed by a processor, the various steps of the method for determining the top hole size of a large current wide adjustment hollow cathode are implemented.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The present invention can optimize the design of fast and efficient wide current regulation performance for high-current cathodes. The designed hollow cathode current regulation ratio is generally above 1:10, which can meet the electron emission capability requirements of high-power, multi-mode Hall electric propulsion or ion electric propulsion technology;

[0034] 2. The present invention can not only improve the gas ionization rate under low current, but also reduce the electron bunching effect under high current, so that the hollow cathode can maintain a point-like working mode within a wide working current range, thereby improving the wide-range current emission capability of the high-current hollow cathode. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0036] Figure 1 Flowchart of the method for determining the top hole size of the hollow cathode for high current wide adjustment. DETAILED DESCRIPTION

[0037] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0038] Example 1

[0039] According to the present invention, a method for determining the top hole size of a large current wide adjustment hollow cathode is provided. Figure 1 As shown, including:

[0040] Step 1: Set the operating current range of the hollow cathode;

[0041] Step 2: Calculate the minimum current operating point I l The corresponding optimal cathode top hole diameter D l ;

[0042] Step 3: Calculate the maximum current operating point I h The corresponding optimal cathode top hole diameter D h ;

[0043] Step 4: According to D l 、D h 、D c With L c The optimal cathode top hole diameter D is determined by the correlation formula c and length L c .

[0044] In this embodiment, the operating current range of the hollow cathode is 2 to 200A.

[0045] In this embodiment, the minimum current is defined in the range of 2 to 10A.

[0046] The minimum current operating point I in step 2 l The corresponding optimal cathode top hole diameter D l The calculation method is:

[0047]

[0048] This formula increases the gas ionization rate in the cathode top region and realizes the convergence effect of neutral gas in the top hole region, so as to adapt to the discharge state where the gas ionization collision free path is insufficient under low flow rate and small current.

[0049] In this embodiment, the maximum current is defined in the range of 80 to 200A.

[0050] The maximum current operating point I in step 3 h The corresponding optimal cathode top hole diameter D h The calculation method is:

[0051]

[0052] This formula enlarges the aperture of the cathode top hole to reduce the frequency of electron-atom excitation and elastic collision under high-density background gas, so as to adapt to the discharge state where the free path of gas excitation collision is too high under high flow rate and large current, that is, the electron bunching effect.

[0053] In this embodiment, D in step 4 l 、D h 、D c With L c The correlation formula is:

[0054]

[0055] This set of formulas expands the cathode top hole diameter while extending the cathode top length to take into account both the problem of insufficient ionization rate under low current and the problem of electron bunching under high current.

[0056] The present invention also provides a large current width adjustment hollow cathode top hole size determination system, which can be implemented by executing the process steps of the large current width adjustment hollow cathode top hole size determination method, that is, those skilled in the art can understand the large current width adjustment hollow cathode top hole size determination method as a preferred implementation of the large current width adjustment hollow cathode top hole size determination system.

[0057] Although the optimal cathode top hole diameter can be determined based on the maximum or minimum operating current, a cathode top hole design corresponding to a small current will result in a higher electron bunching effect under high current conditions, and a cathode top hole design corresponding to a large current will result in a lower ionization rate under low current conditions. Therefore, in order to balance maintaining the ionization rate and avoiding the electron bunching effect under a wide range of operating currents, a strategy of simultaneously expanding the cathode top hole diameter and extending the cathode top length is proposed. This can achieve a high-performance "point-like operating mode" for the hollow cathode over a wide operating current range. All structural modifications, material replacements, formula changes, and gas working medium replacements carried out within the spirit and principles of this invention should be included within the scope of protection of this invention.

[0058] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A method for determining the top hole size of a large current wide adjustment hollow cathode, characterized in that: include Step S1: determining the operating current range of the hollow cathode; Step S2: Calculate the minimum current operating point I l The corresponding optimal cathode top hole diameter D l ; Step S3: Calculate the maximum current operating point I h The corresponding optimal cathode top hole diameter D h ; Step S4: According to the minimum current operating point I l The corresponding optimal cathode top hole diameter D l , Maximum current operating point I h The corresponding optimal cathode top hole diameter D h , optimal cathode top hole diameter D c and length L c The optimal cathode top hole diameter D is determined by the correlation formula c and length L c .

2. The method for determining the top hole size of a large current wide adjustment hollow cathode according to claim 1, characterized in that: The step S2 comprises:

3. The method for determining the top hole size of a large current wide adjustment hollow cathode according to claim 1, characterized in that: The step S3 comprises:

4. The method for determining the top hole size of a large current wide adjustment hollow cathode according to claim 1, characterized in that: The step S4 comprises:

5. A large current wide adjustment hollow cathode top hole size determination system, characterized in that: include Module M1: Determine the operating current range of the hollow cathode; Module M2: Calculate the minimum current operating point I l The corresponding optimal cathode top hole diameter D l ; Module M3: Calculate the maximum current operating point I h The corresponding optimal cathode top hole diameter D h ; Module M4: According to the minimum current operating point I l The corresponding optimal cathode top hole diameter D l , Maximum current operating point I h The corresponding optimal cathode top hole diameter D h , optimal cathode top hole diameter D c and length L c The optimal cathode top hole diameter D is determined by the correlation formula c and length L c .

6. The large current wide adjustment hollow cathode top hole size determination system according to claim 5, characterized in that: The module M2 includes:

7. The large current wide adjustment hollow cathode top hole size determination system according to claim 5, characterized in that: The module M3 includes:

8. The large current wide adjustment hollow cathode top hole size determination system according to claim 5, characterized in that: The module M4 includes:

9. An electronic device comprising a memory and at least one processor, wherein the memory stores instructions; The at least one processor calls the instructions in the memory to enable the electronic device to execute each step of the method for determining the top hole size of a large current wide adjustment hollow cathode according to any one of claims 1 to 4.

10. A computer-readable storage medium having instructions stored thereon, characterized in that: When the instructions are executed by the processor, the various steps of the method for determining the top hole size of a large current wide adjustment hollow cathode as claimed in any one of claims 1 to 4 are implemented.

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