Plasma generation device and method based on multi-level magnetic field and multi-section nozzle

Abstract

The present invention relates to a plasma acceleration propulsion device, and in particular to a plasma generation device and method based on a multi-stage magnetic field and a multi-stage nozzle. The present invention solves the technical problem that a plasma generation device with a single-stage nozzle is not conducive to optimizing the magnetic field configuration, making it difficult to control the trajectory of the plasma jet, resulting in unsatisfactory specific impulse and thrust. The device of the present invention includes a working fluid supply distribution unit and a plasma generation acceleration unit. The working fluid supply distribution unit includes a working fluid distributor, a second insulator, a transition electrode and a third insulator coaxially arranged from the inside to the outside; the plasma generation acceleration unit includes an n-stage nozzle, an n-1-stage first insulator, an accelerator electric field power supply corresponding to the nozzle, an electromagnetic coil corresponding to the nozzle, and an electromagnetic field power supply corresponding to the electromagnetic coil; the n-stage nozzle and the n-1-stage first insulator form a nozzle assembly. The present invention also provides a plasma generation method based on a multi-stage magnetic field and a multi-stage nozzle.

Description

Technical Field

[0001] The present invention relates to a plasma acceleration propulsion technology, and in particular to a plasma generation device and method based on a multi-level magnetic field and a multi-segment nozzle. Background Art

[0002] Plasma acceleration technology can be applied to the research and development of products that specifically require plasma jets, such as space propulsion devices or high-power plasma torches. As a thrust device, it has the advantages of high specific impulse, long life, compact structure, small size and light pollution. It is an important development direction of space propulsion devices at present. Its basic principle is to use electrical energy to heat and dissociate the working fluid, and accelerate the working fluid to form a high-speed jet to generate propulsion technology. At present, the world's major aerospace powers have carried out a lot of research and exploration on different types of plasma propulsion products, and some products have been successfully applied in orbit. Using these products as plasma torch products can increase the jet speed and plasma density, and can expand their application in industries such as solid waste treatment or surface treatment.

[0003] In conventional chemical rocket engines, the thermal energy in the combustion gas is generally converted into kinetic energy through a gas dynamic nozzle (i.e., Laval nozzle) for acceleration and thus thrust generation. In electric propulsion and plasma generation devices, in addition to the self-induced magnetic field, an external magnetic field can be used to subject the plasma to the Lorentz force, thereby generating thrust by converting the circumferential kinetic energy into axial kinetic energy, i.e., utilizing the magnetic nozzle effect for acceleration.

[0004] Existing plasma generation devices are mainly single-stage magnetic field and single-section nozzles. Their specific impulse and thrust are difficult to meet the requirements of magnetic plasma thrusters and related plasma generation devices. At the same time, it is not conducive to optimizing the magnetic field configuration, making it difficult to control the trajectory of the plasma jet, and thus difficult to improve the acceleration effect of the plasma. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problem that the existing plasma generation device with a single-stage magnetic field and a single-stage nozzle is not conducive to optimizing the magnetic field configuration, making it difficult to control the trajectory of the plasma jet, and thus difficult to improve the electromagnetic acceleration effect, resulting in unsatisfactory specific impulse and thrust, and to provide a plasma generation device and method based on a multi-stage magnetic field and a multi-stage nozzle. In the present invention, setting a multi-stage segmented magnetic field is more conducive to optimizing the magnetic field configuration. By adjusting the coil current intensity, the direction of the magnetic field lines along the nozzle axis can be optimized. That is to say, after designing a multi-stage magnetic field, the magnetic field configuration is adjustable. By setting the size of the coil current of each magnetic field segment, the optimal configuration is generated to adapt to the nozzle geometry to provide acceleration performance.

[0006] The technical solution of the present invention is:

[0007] A plasma generation device based on a multi-level magnetic field and a multi-stage nozzle includes a working fluid supply distribution unit and a plasma generation acceleration unit, and its special features are:

[0008] The working fluid supply and distribution unit comprises a working fluid distributor, a second insulator, a transition electrode and a third insulator coaxially arranged from the inside to the outside; the working fluid introduced into the working fluid distributor is an inert gas, nitrogen or air;

[0009] The plasma generation acceleration unit comprises n sections of nozzles, n-1 sections of first insulators, an accelerator electric field power supply corresponding to each section of the nozzle, an electromagnetic coil arranged outside each section of the nozzle, and an electromagnetic field power supply corresponding to the electromagnetic coil; wherein n≥2;

[0010] The n sections of the nozzle and the n-1 sections of the first insulator are spaced apart in the axial direction to form a nozzle assembly; the inner surface of the first insulator maintains a smooth transition with the inner surface of the nozzle, and the diameter of the nozzle assembly gradually increases along the outlet direction of the nozzle assembly;

[0011] The small end of the nozzle assembly is sleeved on the third insulator;

[0012] The negative electrodes of all accelerator electric field power supplies are connected to the working fluid distributor, and the positive electrodes thereof are connected to the corresponding nozzles respectively; the accelerator electric field power supplies are used to generate an arc between the working fluid distributor and the corresponding nozzle;

[0013] The electromagnetic field power supply is used to supply power to the corresponding electromagnetic coil and generate a magnetic field in the corresponding nozzle, and the magnetic field strength generated by the electromagnetic coil farther away from the small end of the nozzle assembly is smaller; the magnetic field lines are directed toward the large end of the nozzle assembly.

[0014] Furthermore, the nozzle assembly is designed according to the Laval nozzle principle and meets the aerodynamic acceleration conditions of supersonic media.

[0015] Furthermore, the nozzle is made of molybdenum metal;

[0016] The working fluid distributor is made of oxide-dispersed strengthened tungsten alloy;

[0017] The first insulator, the second insulator and the third insulator are all made of boron nitride ceramics.

[0018] Furthermore, the working fluid introduced into the working fluid distributor is an inert gas; the magnetic induction intensity of the magnetic field is 0.1T-1T; the accelerator electric field power supply is a constant current mode power supply, and the applicable maintenance current range is 100A-500A.

[0019] Furthermore, the n=3. The design of the three-segment nozzle is conducive to the optimization of the nozzle profile and the optimization of the segmented magnetic field structure and design parameters, while avoiding a large increase in system weight.

[0020] A plasma generation method based on a multi-level magnetic field and a multi-stage nozzle, which is special in that it includes the following steps:

[0021] Step 1) Electrically connect the plasma generating device

[0022] The n sections of the nozzle are connected to the positive pole of the electric field power supply of each accelerator respectively; the working fluid distributor 3 is connected to the negative pole of the electric field power supply of each accelerator; the electromagnetic coil on each section of the nozzle is connected to the electromagnetic field power supply of each accelerator respectively;

[0023] Step 2) Preset the starting voltage of the plasma generating device

[0024] Set the corresponding starting voltage for each nozzle section respectively, and the starting voltage is set according to the working fluid type;

[0025] Step 3) Preset the maintaining current of the plasma generating device

[0026] Preset the maintenance current of each nozzle arc;

[0027] After the arc is established, each accelerator electric field power supply will automatically enter the constant current mode to maintain the arc. The preset value of the constant current mode maintenance current is matched and set according to the type and flow of the working fluid.

[0028] Step 4) Adjust the magnetic induction intensity of the electromagnetic coil of the plasma generating device

[0029] The magnetic induction intensity of the electromagnetic coil is adjusted by adjusting the output current of each electromagnetic field power supply;

[0030] The magnetic field configuration satisfies the working principle of the magnetic nozzle, and the magnetic field intensity gradually weakens near the outlet along the nozzle axis.

[0031] Step 5) The plasma generating device enters the startup phase

[0032] The electric field power supply of each accelerator is turned on, and then the working fluid is introduced into the working fluid distributor 3, and the power supply system detects that the current path is established;

[0033] Step 6) Plasma generating device enters working stage

[0034] After the current path is established, each accelerator electric field power supply automatically enters the constant current mode to maintain the arc. Each accelerator electric field power supply outputs according to the preset current. When the working fluid flow meets the stable working conditions, the arc will be maintained, the working fluid will be continuously ionized, and the generated plasma will be ejected from the outlet at high speed under the magnetic nozzle effect and the acceleration effect of the nozzle geometric expansion profile.

[0035] Step 7) Plasma generation device acceleration performance adjustment stage

[0036] During the operation of the plasma generating device, the plasma jet shape and jet velocity at the nozzle assembly outlet are regulated by adjusting the working fluid supply flow, the maintaining current parameters of each accelerator electric field power supply and the output current parameters of each electromagnetic field power supply.

[0037] Further, in step 2), the working fluid type is an inert gas, and the starting voltage is set to the kilovolt level;

[0038] In step 3), the maintaining current of the constant current mode is set to 100A-500A;

[0039] In step 4), the magnetic induction intensity is 0.1T-1T.

[0040] Beneficial effects of the present invention:

[0041] 1. Compared with a single anode, the device of the present invention can generate and maintain an arc at each stage of the segmented nozzle (i.e., segmented anode). After the working fluid enters the discharge channel, it is ionized more fully. At the same time, the plasma is accelerated more evenly under the multi-stage arc self-induced magnetic field, and a greater thrust can be obtained than that of a single-stage nozzle.

[0042] 2. The device of the present invention adopts multi-anode nozzle segmentation, and fully utilizes the magnetic nozzle effect and the Laval nozzle aerodynamic effect to accelerate the plasma, thereby obtaining a higher specific impulse.

[0043] 3. The device of the present invention adopts a multi-stage segmented magnetic field, which is more conducive to the optimization of the magnetic field configuration. By adjusting the coil current intensity, the direction of the magnetic force lines along the nozzle axis can be optimized, that is, the divergence direction of the magnetic force lines and the angle of the nozzle profile direction tend to be consistent. After the charged particles are accelerated and ejected from the nozzle, they are more easily separated from the magnetic force lines, thereby reducing thrust loss.

[0044] 4. The device of the present invention adopts a plasma generation device combining a multi-stage nozzle and a multi-stage magnetic field, which has a wider acceleration range, that is, a larger acceleration range and a thrust adjustment range, and is suitable for a wider range of application scenarios. When used as an electric propulsion thruster, the variable thrust / variable specific impulse range is wider.

[0045] 5. The method of the present invention further optimizes the magnetic field configuration of the multi-level magnetic field, thereby improving the trajectory control and electromagnetic acceleration effect of the plasma jet.

[0046] 6. The method of the present invention is conducive to the smooth start of the arc and the improvement of the acceleration voltage under the action of the transition electrode and the multi-segment anode, thereby ensuring the ignition reliability and electric field acceleration capability of the generating device.

[0047] 7. The segmented nozzle and multi-level magnetic field in the method of the present invention are conducive to the matching of magnetic field configuration and arc characteristics, which can optimize the jet trajectory, improve the electromagnetic acceleration effect and specific impulse of the working fluid, and reduce the ablation rate and heat loss of the nozzle. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a structural schematic diagram of the device of the present invention.

[0049] Explanation of the reference numerals: 1-nozzle, 3-working fluid distributor, 4-transition electrode, 5-first insulator, 6-second insulator, 7-third insulator, 11-accelerator electric field power supply, 21-electromagnetic field power supply. DETAILED DESCRIPTION

[0050] See also Figure 1 The present invention discloses a plasma generating device based on a multi-level magnetic field and a multi-stage nozzle, including a working fluid supply distribution unit and a plasma generating acceleration unit. The entire plasma generating device is a coaxial structure.

[0051] The working fluid supply distribution unit includes a working fluid distributor 3, a second insulator 6, a transition electrode 4 and a third insulator 7 which are coaxially arranged from the inside to the outside; the working fluid introduced into the working fluid distributor 3 is an inert gas, nitrogen or air; in this embodiment, the working fluid is an inert gas. The working fluid distributor 3 is made of a reinforced tungsten alloy dispersed with oxides. Therefore, the working fluid distributor 3 made of this material also has the function of a cathode, and has the characteristics of easy electron emission and low starting voltage; the first insulator 5, the second insulator 6 and the third insulator 7 are all made of boron nitride ceramics with good machining performance and insulation performance.

[0052] The plasma generation acceleration unit includes a three-section nozzle 1, two sections of first insulators 5, an accelerator electric field power supply 11 corresponding to each section of the nozzle 1, an electromagnetic coil arranged outside each section of the nozzle, and an electromagnetic field power supply 21 corresponding to the electromagnetic coil; the three sections of the nozzle 1 and the two sections of the first insulators 5 are arranged at intervals along the axial direction to form a nozzle assembly, the inner surface of the first insulator 5 and the inner surface of the nozzle 1 maintain a smooth transition, and the diameter of the nozzle assembly gradually increases along the outlet direction of the nozzle assembly; the nozzle assembly is designed according to the Laval nozzle principle and meets the aerodynamic acceleration conditions of supersonic media. The small end of the nozzle assembly is sleeved on the third insulator 7; the negative poles of all accelerator electric field power supplies 11 are connected to the working fluid distributor 3, and the positive poles thereof are respectively connected to the corresponding nozzles 1; the accelerator electric field power supply 11 is used to generate an arc between the working fluid distributor 3 and the corresponding nozzle 1, and the arc trend is as follows Figure 1As shown by the arrow arc in the middle; the electromagnetic field power supply 21 is used to power the corresponding electromagnetic coil and generate a magnetic field in the corresponding nozzle 1, and the magnetic field strength generated by the electromagnetic coil farther away from the small end of the nozzle assembly is smaller; the magnetic field lines are directed toward the large end of the nozzle assembly. The nozzle 1 is made of high-temperature resistant material molybdenum, which can reduce ablation during the operation of the accelerator and extend the life of the accelerator. The working fluid introduced into the working fluid distributor 3 is an inert gas; the magnetic induction intensity of the corresponding magnetic field is set to 0.1T-1T; the accelerator electric field power supply 11 is a constant current mode power supply, and the applicable maintenance current is 100A-500A.

[0053] The present invention also provides a plasma generation method based on a multi-level magnetic field and a multi-stage nozzle, which is used in the plasma generation device described above, and comprises the following steps:

[0054] Step 1) Electrically connect the plasma generating device

[0055] The three sections of the nozzle 1 are connected to the positive poles of the accelerator electric field power supplies 11 respectively; the working fluid distributor 3 is connected to the negative poles of the accelerator electric field power supplies 11; the electromagnetic coil on each section of the nozzle 1 is connected to the electromagnetic field power supply 21 respectively;

[0056] Step 2) Preset the starting voltage of the plasma generating device

[0057] A corresponding starting voltage is set for each section of the nozzle 1, and the starting voltage is set according to the type of working fluid. In this embodiment, the working fluid is an inert gas, and the starting voltage is set to the kilovolt level. The starting voltage is used to ensure that the working fluid is broken down to form a current path.

[0058] Step 3) Preset the maintaining current of the plasma generating device

[0059] Presetting the arc maintenance current in each section of the nozzle 1;

[0060] After the arc is established, each accelerator electric field power supply 11 will automatically enter the constant current mode to maintain the arc. The preset value of the maintaining current in the constant current mode is related to the type and flow of the working fluid introduced. The preset value of the maintaining current in the constant current mode and the feedback voltage are matched and set according to the type and flow of the working fluid introduced. The working fluid adopts inert gas, the maintaining current in the constant current mode is set to 100A-500A, the feedback voltage is on the order of 100 volts, and the overall power of the plasma generation device is tens of kilowatts.

[0061] Step 4) Adjust the magnetic induction intensity of the electromagnetic coil of the plasma generating device

[0062] The magnetic induction intensity of the electromagnetic coil is adjusted by adjusting the output current of each electromagnetic field power supply 21; the working fluid adopts inert gas to maintain the magnetic induction intensity at 0.1T-1T;

[0063] The magnetic field configuration satisfies the working principle of the magnetic nozzle, and the magnetic field intensity gradually weakens near the nozzle assembly outlet along the nozzle assembly axis.

[0064] Step 5) The plasma generating device enters the startup phase

[0065] The electric field power supplies 11 of each accelerator are turned on, and then the working fluid is introduced into the working fluid distributor 3, and the working fluid is an inert gas; the power supply system detects that the current path is established;

[0066] Step 6) Plasma generating device enters working stage

[0067] After the current path is established, each accelerator electric field power supply 11 automatically enters the constant current mode to maintain the arc. Each accelerator electric field power supply 11 outputs according to the preset current. When the working fluid flow rate meets the stable working condition, the arc will be maintained, the working fluid is continuously ionized, and the generated plasma is ejected from the nozzle assembly outlet at a high speed under the magnetic nozzle effect and the acceleration effect of the nozzle geometric expansion profile;

[0068] Step 7) Plasma generation device acceleration performance adjustment stage

[0069] During the operation of the plasma generation device, the plasma jet morphology and jet velocity at the outlet of the nozzle assembly are regulated by adjusting the working fluid supply flow rate, the maintaining current parameters of each accelerator electric field power supply 11 and the output current parameters of each electromagnetic field power supply 21 (mainly affecting the magnetic induction intensity and the overall magnetic field configuration); within the matching range, increasing the gas supply flow rate and the power supply maintaining current parameters will cause the plasma density at the jet outlet to increase, while increasing the magnetic induction intensity will cause the jet velocity to increase.

[0070] The present invention adopts a multi-level magnetic field and a multi-segment nozzle 1 design for the traditional magnetic nozzle part. The multi-level magnetic field further optimizes the magnetic field configuration, improves the trajectory control and electromagnetic acceleration effect of the plasma jet; the multi-segment nozzle 1 forms a multi-level anode, which is conducive to improving the acceleration voltage of the nozzle assembly and enhancing the electric field acceleration capability, thereby obtaining a higher speed and a higher specific impulse. At the same time. A set of electromagnetic coils is arranged outside each section of the nozzle 1, and each set of electromagnetic coils and nozzles has its own power supply system. The plasma jet is accelerated by the combined action of the discharge arc's own magnetic field, the magnetic field generated by each stage of the coil, the electric field generated by each section of the nozzle, and the aerodynamic force, thereby realizing multi-field acceleration of the plasma, obtaining a higher specific impulse and thrust, and broadening the application scenarios of plasma technology.

[0071] Applying the design concept of the present invention to the design of a magnetic plasma thruster and a high-power plasma torch can improve the ionization rate of the magnetic nozzle, increase the specific impulse of the magnetic plasma thruster and the jet velocity of the plasma torch.

[0072] The method of the present invention can be widely applied to magnetic plasma thrusters and related plasma generation devices, and has broad application prospects.

Claims

1. A plasma generation device based on a multi-level magnetic field and a multi-stage nozzle, comprising a working fluid supply distribution unit and a plasma generation acceleration unit, characterized in that: The working fluid supply and distribution unit comprises a working fluid distributor (3), a second insulator (6), a transition electrode (4) and a third insulator (7) which are coaxially arranged from the inside to the outside; the working fluid introduced into the working fluid distributor (3) is an inert gas, nitrogen or air; The plasma generation acceleration unit comprises n sections of nozzles (1), n-1 sections of first insulators (5), an accelerator electric field power supply (11) corresponding to each section of the nozzle (1), an electromagnetic coil arranged outside each section of the nozzle (1), and an electromagnetic field power supply (21) corresponding to the electromagnetic coil; wherein n≥2; The n sections of the nozzle (1) and the n-1 sections of the first insulator (5) are arranged at intervals along the axial direction to form a nozzle assembly; the inner surface of the first insulator (5) and the inner surface of the nozzle (1) maintain a smooth transition, and the diameter of the nozzle assembly gradually increases along the outlet direction of the nozzle assembly; The small end of the nozzle assembly is sleeved on the third insulator (7); The negative electrodes of all accelerator electric field power supplies (11) are connected to the working fluid distributor (3), and the positive electrodes thereof are respectively connected to the corresponding nozzles (1); the accelerator electric field power supplies (11) are used to generate an arc between the working fluid distributor (3) and the corresponding nozzles (1); The electromagnetic field power supply (21) is used to supply power to the corresponding electromagnetic coil and generate a magnetic field in the corresponding nozzle (1), and the magnetic field intensity generated by the electromagnetic coil farther away from the small end of the nozzle assembly is smaller; the magnetic field lines are directed toward the large end of the nozzle assembly; the nozzle assembly is designed according to the Laval nozzle principle and meets the aerodynamic acceleration conditions of the supersonic medium.

2. The plasma generating device based on a multi-level magnetic field and a multi-stage nozzle according to claim 1, characterized in that: The nozzle (1) is made of molybdenum metal; The working fluid distributor (3) is made of oxide-dispersed reinforced tungsten alloy; The first insulator (5), the second insulator (6) and the third insulator (7) are all made of boron nitride ceramics.

3. The plasma generating device based on multi-level magnetic field and multi-stage nozzle according to claim 2, characterized in that: The working fluid introduced into the working fluid distributor (3) is an inert gas; the magnetic induction intensity of the magnetic field is 0.1T-1T; the accelerator electric field power supply (11) is a constant current mode power supply, and the applicable maintenance current is 100A-500A.

4. The plasma generating device based on multi-level magnetic field and multi-stage nozzle according to claim 3 is characterized in that: Said n=3.

5. A plasma generation method based on a multi-level magnetic field and a multi-stage nozzle, implemented by using the plasma generation device based on a multi-level magnetic field and a multi-stage nozzle according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1) Make electrical connections to the plasma generation device: The n sections of the nozzle (1) are respectively connected to the positive poles of the electric field power supplies (11) of the respective accelerators; the working fluid distributor (3) is connected to the negative poles of the electric field power supplies (11) of the respective accelerators; and the electromagnetic coil on each section of the nozzle (1) is respectively connected to the electromagnetic field power supplies (21) of the respective accelerators; Step 2) Preset the starting voltage of the plasma generating device: A corresponding starting voltage is set for each nozzle section (1), and the starting voltage is set according to the type of working fluid; Step 3) Preset the maintaining current of the plasma generating device: Presetting the arc maintenance current in each nozzle section (1); After the arc is established, each accelerator electric field power supply (11) will automatically enter a constant current mode to maintain the arc, and the preset value of the maintaining current in the constant current mode is matched and set according to the type and flow of the working fluid introduced; Step 4) Adjust the magnetic induction intensity of the electromagnetic coil of the plasma generating device: The magnetic induction intensity of the electromagnetic coil is adjusted by adjusting the output current of each electromagnetic field power supply (21), so that the magnetic field configuration satisfies the working principle of the magnetic nozzle, and the magnetic field intensity gradually weakens near the nozzle assembly outlet along the nozzle assembly axis direction; Step 5) The plasma generation device enters the startup phase: The electric field power supplies (11) of each accelerator are turned on, and then the working fluid is introduced into the working fluid distributor (3), and the power supply system detects that a current path is established; Step 6) The plasma generating device enters the working stage: After the current path is established, each accelerator electric field power supply (11) automatically enters a constant current mode to maintain the arc. Each accelerator electric field power supply (11) outputs according to a preset current. When the working fluid flow rate meets the stable working condition, the arc will be maintained, the working fluid is continuously ionized, and the generated plasma is ejected from the nozzle assembly outlet at a high speed under the magnetic nozzle effect and the acceleration effect of the nozzle geometric expansion profile; Step 7) Plasma generation device acceleration performance adjustment stage During the operation of the plasma generating device, the plasma jet shape and jet velocity at the outlet of the nozzle assembly are regulated by adjusting the working fluid supply flow rate, the maintaining current parameters of each accelerator electric field power supply (11) and the output current parameters of each electromagnetic field power supply (21).

6. The plasma generation method based on multi-level magnetic field and multi-stage nozzle according to claim 5, characterized in that: In step 2), the working fluid type is inert gas, and the starting voltage is set to the kilovolt level; In step 3), the maintaining current of the constant current mode is set to 100A-500A; In step 4), the magnetic induction intensity is 0.1T-1T.

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