CN105857647B - The production method for accelerating racemization magnetic field of low speed spin space unmagnetized metal fragment - Google Patents

Abstract

The present invention relates to a kind of production methods for accelerating racemization magnetic field of low speed spin space unmagnetized metal fragment, apply variation magnetic field using on the direction mutually orthogonal with constant racemization magnetic field, so as to generate vortex in fragment conductor, with acted in stationary magnetic field under fragment rotary motion generate vortex collective effect, to enhance the eddy current effect inside low speed rotation fragment, the racemization torque under the effect of stationary magnetic field is improved, shortens a kind of magnetic field setting method of fragment racemization time.The method of the present invention compared with the existing technology has the following advantages：Vortex is generated using variation magnetic field, the vortex generated in magnetic field with unmagnetized metal fragment rotary motion is superimposed, and is generated racemization torque, is improved the efficiency of energy transmission, increase racemization torque, reduce the racemization time.

Description

Generation method of accelerated derotation magnetic field of non-magnetized metal fragments in low-speed spin space

technical field

The invention belongs to the technical field of space debris cleaning, and relates to a magnetic field technology for derotating space non-magnetized metal fragments, in particular to a method for generating an accelerated derotation magnetic field of low-speed spin space non-magnetized metal fragments.

Background technique

"Space debris" means non-functional man-made objects in Earth orbit or re-entering the atmosphere, including fragments and components thereof. With the increasing frequency of human spaceflight activities, the number of space debris is increasing exponentially, and they are concentrated in areas with an altitude of 800-1000km. Due to the influence of space perturbation, these debris are often in a state of high-speed spin motion. This has brought great difficulties to the capture and clean-up of space debris. Derotation of space debris is a top priority for capture and cleanup. At present, there are mainly contact racemization and non-contact racemization. The magnetic field-based eddy current derotation technology for space debris belongs to the non-contact derotation. This research is still in its infancy. Existing research mainly focuses on the derotation method under a constant magnetic field, without considering the interaction between a constant magnetic field and a changing magnetic field. Magnetic field setting method.

In the article "Study on the eddycurrent damping of the spin dynamics of space debris from the Ariane launcherupper stages" published in "ACTA ASTRONAUTICA" 2012, Volume 76, pages 145-153 (author Praly, N., etc.), discussed the The eddy current effect of the space debris produced by the upper stage of the Yana rocket under the action of the earth's magnetic field leads to the conclusion that the space debris will gradually stop spinning under the action of the earth's magnetic field. It is theoretically shown that a constant magnetic field will dampen the rotational motion of space debris. This passive racemization takes a long time, usually about half a year.

In the article "Eddy currents applied to de-tumbling of space debris: Analysis and validation of approximate proposed methods" (authors Gomez, Natalia Ortiz, etc.) published in "ACTA ASTRONAUTICA", Volume 114, pages 34-53, 2015, it is proposed to establish a constant Magnetic field, active derotation technology using eddy current torque. In this method, the derotation of space debris is achieved by actively constructing a directional magnetic field, and the magnitude of the eddy current torque and the derotation time are studied. This technology establishes a constant magnetic field through a single set of coils, and relies on the movement of fragments to cut the magnetic field lines to generate eddy currents and generate derotation torque. Since the size of the vortex is related to the velocity of the debris, the faster the velocity of the debris, the larger the vortex, and the greater the derotation torque. When the rotational speed of the debris is slower, the derotation torque will be smaller. The rotation speed of the fragments will become smaller and smaller, the derotation torque will also become smaller and smaller, and the time required for derotation will be longer.

The national invention patent "A Method and Device for Removing Space Debris" applied in 2013, patent application publication number CN103434658A, inventor: Li Yiyong, etc., proposed to change the movement of space debris through the combination of electric field force, magnetic field force or electromagnetic field force Speed and direction of motion, a method of removing space debris that deviates debris from a fixed orbit. This technique does not address the rotational motion and racemization of the fragments.

The prior art analyzes the generation mechanism and realization method of the eddy current torque. The magnetic field used is a constant magnetic field, and the derotation is performed only by the eddy current torque generated by the rotational motion of the debris itself. Since the size of the vortex is related to the moving speed of the fragments, the faster the moving speed of the fragments, the larger the vortex, and the greater the derotation torque; when the rotational speed of the fragments is slower, the derotation torque will be smaller. During the derotation process, the rotational speed of the fragments will become smaller and smaller, the derotation torque will also become smaller and smaller, and the time required for derotation will be longer.

Contents of the invention

technical problem to be solved

In order to avoid the deficiencies of the prior art, the present invention proposes a method for generating an accelerated derotation magnetic field for non-magnetized metal fragments in low-speed spin space, using a changing magnetic field to generate eddy currents on the non-magnetized metal fragments, and moving with the fragments in the magnetic field The generated eddy currents work together to form a changing magnetic field of eddy current torque, enhance the eddy current torque, accelerate the de-rotation process, and improve the de-rotation efficiency.

Technical solutions

A method for generating an accelerated derotation magnetic field of non-magnetized metal fragments in a low-speed spin space, characterized in that: an alternating magnetic field is applied in the orthogonal direction of a constant magnetic field, and eddy currents are jointly generated inside the fragment conductors to enhance eddy current torque and accelerate The racemization process, the specific steps are as follows:

Step 1: In a plane perpendicular to the main axis of rotation of the non-magnetized metal fragments, with the passing point of the main axis of the fragments as the origin, select two arbitrary mutually perpendicular directions as the x-axis and the y-axis, and apply a magnetic field M and Magnetic field N; the positive direction of the magnetic field M is the negative direction of the y-axis, and the positive direction of the magnetic field N is the positive direction of the x-axis;

Step 2: Determine the conditions that produce derotation torque:

1. When the magnetic field M has a constant magnetic field strength H ₁ , the magnetic field N is a changing magnetic field strength H ₂ :

Case 1: When the pieces rotate counterclockwise:

If the constant magnetic field strength H ₁ of the magnetic field M > 0, the magnetic field N applies a changing magnetic field strength H ₂ to decrease along the positive direction of the x-axis, as

If the magnetic field M has a constant magnetic field strength H ₁ <0, the magnetic field N applies a changing magnetic field strength H ₂ to increase along the positive direction of the x-axis, as

Case 2: When the pieces rotate clockwise:

If the constant magnetic field strength H ₁ of the magnetic field M > 0, the magnetic field N applies a changing magnetic field strength H ₂ to increase along the positive direction of the x-axis, as

If the magnetic field M with a constant magnetic field strength H ₁ <0, the magnetic field N applied with a changing magnetic field strength H ₂ decreases along the positive direction of the x-axis, as

2. The magnetic field M has a variable magnetic field strength H ₁ , and the magnetic field N has a constant magnetic field strength H ₂ ;

Case 1: When the pieces rotate counterclockwise:

If the constant magnetic field strength H ₂ of the magnetic field N > 0, the magnetic field M applies a changing magnetic field strength H ₁ to increase along the negative direction of the y-axis, as

If the constant magnetic field strength H ₂ of the magnetic field N <0, the magnetic field M applies a changing magnetic field strength H ₁ and decreases along the negative direction of the y-axis, as

Case 2: When the pieces rotate clockwise:

If the constant magnetic field strength H ₂ of the magnetic field N > 0, the magnetic field M applies a changing magnetic field strength H ₁ to decrease along the negative direction of the y-axis, as

If the constant magnetic field strength H ₂ of the magnetic field N <0, the magnetic field M applies a changing magnetic field strength H ₁ to increase along the negative direction of the y-axis, as

The applied alternating magnetic field is square wave, triangular wave, sawtooth wave or trapezoidal wave.

Beneficial effect

The invention proposes a method for generating the accelerated derotation magnetic field of non-magnetized metal fragments in low-speed spin space, which uses a changing magnetic field in a direction perpendicular to the constant derotation magnetic field to generate eddy currents inside the fragment conductors, which is the same as that in the fragment conductors. The eddy currents generated by the rotational movement of fragments under the action of a constant magnetic field work together to enhance the eddy current effect inside the low-speed rotating fragments, increase the derotation torque under the action of a constant magnetic field, and shorten the derotation time of the fragments. A magnetic field setting method.

Compared with the prior art, the method of the present invention has the following advantages: the eddy current generated by the changing magnetic field is superimposed with the eddy current generated by the rotational motion of the non-magnetized metal fragments in the magnetic field to generate a derotation torque, which improves the efficiency of energy transfer and increases the energy consumption. rotational torque, reducing the derotation time.

Description of drawings

Figure 1: Schematic diagram of the magnetic field action mode

Figure 2: M is a constant magnetic field, and N is a schematic diagram of the induced current when the magnetic field is changing

Figure 3: M is a constant magnetic field, and N is a schematic diagram of the magnetic field setting when the magnetic field is changing

Figure 4: N is a constant magnetic field, and M is a schematic diagram of the induced current when the magnetic field is changing

Figure 5: N is a constant magnetic field, and M is a schematic diagram of the magnetic field setting when the magnetic field is changing

Figure 6: Schematic diagram of magnetic field setup during alternating action

Detailed ways

Now in conjunction with embodiment, accompanying drawing, the present invention will be further described:

The present invention is a kind of changing magnetic field technology that utilizes changing magnetic field to generate eddy current on non-magnetized metal fragments, and interacts with eddy current generated in the magnetic field by fragment movement to form eddy current torque. Its technical feature is that it contains the following contents:

(1) The action form of the magnetic field

In the plane perpendicular to the main axis of rotation of the non-magnetized metal fragments, two mutually perpendicular directions are arbitrarily selected, with the passing point of the main axis of the fragments as the origin, and the two perpendicular directions are respectively marked as x-axis and y-axis. A magnetic field M and a magnetic field N are applied in two axial directions, respectively. For the convenience of discussion, it is stipulated that when the rotation direction of the debris is counterclockwise, it is positive, the positive direction of the magnetic field M is the negative direction of the y-axis, and the positive direction of the magnetic field N is the positive direction of the x-axis;

(2) When the magnetic field M has a constant magnetic field strength H ₁ and the magnetic field N has a variable magnetic field strength H ₂ , the conditions for derotation torque

When the fragments rotate counterclockwise, when the magnetic field M has a constant magnetic field strength H ₁ and is along the negative direction of the y-axis, it is recorded as H ₁ >0, and the direction of the eddy current generated at this time is that the current in the conductor on the upper side of the x-axis flows out of the paper, x The current in the conductor on the underside of the shaft flows into the paper. At this time, the direction of the eddy current torque is opposite to the rotational speed, which belongs to the derotation torque. In order to generate the derotation torque in the same direction, it is required that the direction of the eddy current induced by the magnetic field N in the x-axis direction in the conductor should be the same as the direction of the eddy current when the magnetic field M acts alone, that is, the direction of the induced magnetic field should be along the positive direction of the x-axis, According to Lenz's law, the magnetic field of the induced current should hinder the change of the original magnetic flux. At this time, the condition for the generation of derotation torque is: the magnetic field strength H ₂ of the magnetic field N decreases along the positive direction of the x-axis, which is denoted as Similarly, when H ₁ <0, the condition for derotation torque is: the magnetic field strength H ₂ of the magnetic field N increases along the positive direction of the x-axis, denoted as

It's similar when the fragments rotate clockwise. Only conclusions are given here. That is, the condition for the generation of derotation torque is: when H ₁ <0, the magnetic field strength H ₂ of the magnetic field N decreases along the positive direction of the x-axis, denoted as When H ₁ >0, the magnetic field strength H ₂ of the magnetic field N increases along the positive direction of the x-axis, denoted as

(3) The magnetic field M has a changing magnetic field strength H ₁ , the magnetic field N has a constant magnetic field strength H ₂ , and the conditions for producing derotation torque

When the fragments rotate counterclockwise, when the magnetic field N has a constant magnetic field strength H ₂ and is along the positive direction of the x-axis, that is, when H ₂ >0, the direction of the eddy current generated at this time is that the current in the conductor on the left side of the y-axis flows out of the paper, y The current in the conductor on the right side of the shaft flows into the paper. At this time, the direction of the eddy current torque is opposite to the rotational speed, which belongs to the derotation torque. In order to generate the derotation torque in the same direction, the magnetic field in the y-axis direction is required. The direction of the eddy current induced in the conductor should be the same as that of the N magnetic field acting alone, that is, the direction of the induced magnetic field should be along the positive direction of the y-axis. According to Lenz's law, the magnetic field of the induced current should hinder the change of the original magnetic flux. At this time, the condition for the generation of derotation torque is: the magnetic field strength H ₁ of the magnetic field M increases along the negative direction of the y-axis, which is denoted as Similarly, when H ₂ <0, the condition for the generation of derotation torque is: the magnetic field strength H ₁ of the magnetic field M decreases along the negative direction of the y-axis, which is denoted as

It's similar when the fragments rotate clockwise. Therefore, the condition for the derotation torque is: when H ₂ <0, the magnetic field strength H ₁ of the magnetic field M increases along the negative direction of the y-axis, which is recorded as When H ₂ >0, the magnetic field strength H ₁ of the magnetic field M decreases along the negative direction of the y-axis, which is denoted as

This embodiment is about the magnetic field conditions that generate the derotation torque. The structure of the fragments does not affect the magnetic field conditions. For convenience, the shape of the fragments is selected as a hollow cylinder. The main axis of rotation is located at the centerline of the cylinder and rotates counterclockwise. Select a section perpendicular to the cylinder to establish a Cartesian coordinate system as shown in Figure 1. The origin is the center of the section circle. Take any two perpendicular directions to establish the x-axis and y-axis, and apply them along the x-axis and y-axis respectively. M and N magnetic fields, the magnetic field strengths are H ₁ and H ₂ respectively, and the direction shown in the figure is the positive direction.

As shown in Figure 2, when the debris rotates counterclockwise, when the magnetic field M has a constant magnetic field strength H ₁ and is along the negative direction of the y-axis, it is recorded as H ₁ >0, and the direction of the eddy current generated at this time is in the conductor on the upper side of the x-axis The current flows out of the paper, and the current in the conductor on the lower side of the x-axis flows into the paper. At this time, the direction of the eddy current torque is opposite to the rotational speed, which belongs to the derotation torque. In order to generate the derotation torque in the same direction, it is required that the direction of the eddy current induced by the magnetic field N in the x-axis direction in the conductor should be the same as the direction of the eddy current when the magnetic field M acts alone, that is, the direction of the induced magnetic field should be along the positive direction of the x-axis, According to Lenz's law, the magnetic field of the induced current should hinder the change of the original magnetic flux. At this time, the condition for the generation of derotation torque is: the magnetic field strength H ₂ of the magnetic field N decreases along the positive direction of the x-axis, which is denoted as Similarly, when H ₁ <0, the condition for derotation torque is: the magnetic field strength H ₂ of the magnetic field N increases along the positive direction of the x-axis, denoted as

At this time, the M and N magnetic fields satisfying the magnetic field setting conditions for generating derotation torque can be set as shown in FIG. 3 , but are not limited to the type shown in FIG. 3 . It can be seen from Figure 3 that in the 0-t1 section, the magnetic field strength H ₁ of the M magnetic field is positive, and the rate of change of the magnetic field strength H ₂ of the N magnetic field In the t1-t2 period, the M magnetic field strength _H2 is negative, and the rate of change of the N magnetic field The above process is repeated in the next cycle, and the torque generated at this time is opposite to the movement direction of the debris, which is an anti-rotation torque.

As shown in Figure 4, when the magnetic field N has a constant magnetic field strength H ₂ and is along the positive direction of the x-axis, that is, when H ₂ >0, the direction of the eddy current generated at this time is that the current in the conductor on the left side of the y-axis flows out of the paper, y The current in the conductor on the right side of the shaft flows into the paper. At this time, the direction of the eddy current torque is opposite to the rotational speed, which belongs to the derotation torque. In order to generate the derotation torque in the same direction, the magnetic field in the y-axis direction is required. The direction of the eddy current induced in the conductor should be the same as that of the N magnetic field acting alone, that is, the direction of the induced magnetic field should be along the positive direction of the y-axis. According to Lenz's law, the magnetic field of the induced current should hinder the change of the original magnetic flux. At this time, the condition for the generation of derotation torque is: the magnetic field strength H ₁ of the magnetic field M increases along the negative direction of the y-axis, which is denoted as Similarly, when H ₂ <0, the condition for the generation of derotation torque is: the magnetic field strength H ₁ of the magnetic field M decreases along the negative direction of the y-axis, which is denoted as

At this time, the M and N magnetic fields satisfying the magnetic field setting conditions for generating derotation torque can be set as shown in FIG. 3 , but are not limited to the type shown in FIG. 3 . It can be seen from Figure 3 that in the 0-t1 section, the N magnetic field strength _H2 is positive, and the rate of change of the M magnetic field strength _H1 In the t1-t2 section, the magnetic field strength H ₂ of the N magnetic field is negative, and the change rate of the magnetic field strength H ₁ of the M magnetic field The above process is repeated in the next cycle, and the torque generated at this time is opposite to the movement direction of the debris, which is an anti-rotation torque.

Combining the above two situations, and considering that there must be a change process for the constant magnetic field to change from positive to negative, the two magnetic fields can be set as shown in Figure 4. But it is not limited to the way shown in the figure. As shown in the figure, in the 0-t1 period, M is a constant magnetic field, and H ₁ >0, N is a changing magnetic field, and In the t1-t2 period, N is a constant magnetic field, and H ₂ <0, H ₁ is a changing magnetic field, and In the t2-t3 period, M is a constant magnetic field, and H ₁ <0, N is a changing magnetic field, and In the period t3-t4, N is a constant magnetic field, and H ₂ >0, M is a changing magnetic field, and Repeat the above process in the next cycle. At this time, the direction of the generated torque is opposite to the rotation direction of the debris, which is an anti-rotation torque.

For the case where the fragments rotate clockwise, the detailed conditions have been given in the technical proposal, and no examples are given here.

Claims (2)

1. A method for producing the accelerated derotation magnetic field of non-magnetized metal fragments in low-speed spin space, characterized in that: an alternating magnetic field is applied in the orthogonal direction of the constant magnetic field, and eddy currents are jointly generated inside the fragment conductors to enhance the eddy current torque , to accelerate the racemization process, the specific steps are as follows: Step 1: In the plane perpendicular to the main axis of rotation of the non-magnetized metal fragments, with the passing point of the main axis of the fragments as the origin, select two arbitrary directions perpendicular to each other as the x-axis and the y-axis, and in the two axes of the y-axis and the x-axis Direction to apply magnetic field M and magnetic field N respectively; the positive direction of magnetic field M is the negative direction of y-axis, and the positive direction of magnetic field N is the positive direction of x-axis; Step 2: Determine the conditions that produce derotation torque: 1. When the magnetic field M has a constant magnetic field strength H ₁ , the magnetic field N is a changing magnetic field strength H ₂ : Case 1: When the pieces rotate counterclockwise: If the constant magnetic field strength H ₁ of the magnetic field M > 0, the magnetic field N applies a changing magnetic field strength H ₂ to decrease along the positive direction of the x-axis, as If the magnetic field M has a constant magnetic field strength H ₁ <0, the magnetic field N applies a changing magnetic field strength H ₂ to increase along the positive direction of the x-axis, as Case 2: When the pieces rotate clockwise: If the constant magnetic field strength H ₁ of the magnetic field M > 0, the magnetic field N applies a changing magnetic field strength H ₂ to increase along the positive direction of the x-axis, as If the magnetic field M with a constant magnetic field strength H ₁ <0, the magnetic field N applied with a changing magnetic field strength H ₂ decreases along the positive direction of the x-axis, as 2. The magnetic field M has a variable magnetic field strength H ₁ , and the magnetic field N has a constant magnetic field strength H ₂ ; Case 1: When the pieces rotate counterclockwise: If the constant magnetic field strength H ₂ of the magnetic field N > 0, the magnetic field M applies a changing magnetic field strength H ₁ to increase along the negative direction of the y-axis, as If the constant magnetic field strength H ₂ of the magnetic field N <0, the magnetic field M applies a changing magnetic field strength H ₁ and decreases along the negative direction of the y-axis, as Case 2: When the pieces rotate clockwise: If the constant magnetic field strength H ₂ of the magnetic field N > 0, the magnetic field M applies a changing magnetic field strength H ₁ to decrease along the negative direction of the y-axis, as If the constant magnetic field strength H ₂ of the magnetic field N <0, the magnetic field M applies a changing magnetic field strength H ₁ to increase along the negative direction of the y-axis, as 2. The method for generating the accelerated derotation magnetic field of non-magnetized metal fragments in low-speed spin space according to claim 1, characterized in that: the applied alternating magnetic field is a square wave, a triangular wave, a sawtooth wave or a trapezoidal wave.