CN107645822A - A kind of air intake duct shock wave control device and method based on the electric discharge of surface magnetic control arc - Google Patents

Abstract

The invention proposes an inlet shock wave control device and method based on surface magnetron arc discharge, and relates to the technical fields of plasma and magnetic fluid. 1. Using the combined discharge method of high voltage pulse breakdown-low voltage DC maintenance to generate arc discharge plasma on the inner wall of the intake duct; 2. Installing a permanent magnet in the wall of the intake duct to apply a magnetic field perpendicular to the direction of the wall; 3. Through The thermal effect of the discharge plasma increases the shock angle, and at the same time, under the action of the magnetic field, the Lorentz force in the reverse direction of the flow is generated to decelerate the airflow, and the discharge plasma is constrained to enhance the control effect, so that the inlet shock wave re-intersects the lip. The invention can effectively improve the working performance of the hypersonic air inlet at the non-design Mach number, and widen the stable working range of the aircraft.

Description

A shock wave control device and method for an inlet port based on surface magnetron arc discharge

technical field

The invention relates to the technical fields of plasma and magnetic fluid, in particular to an inlet shock wave control device and method based on surface magnetron arc discharge.

Background technique

The scramjet engine is the core technology of the hypersonic vehicle, which has great military value and potential economic value, and the hypersonic inlet is one of the key components of the scramjet engine. The hypersonic inlet is usually designed for a certain fixed Mach number. When the flight Mach number is greater than the design Mach number, the shock wave will enter the inlet, form a reflected shock wave, and interact with the boundary layer to cause the boundary layer to separate. The performance of the intake port drops sharply, and even causes the intake port to surge and fail to start.

At present, the flow control of the inlet generally adopts the method of mechanical variable geometry and aerodynamic variable geometry flow control, which can adjust the shock wave system and internal contraction ratio of the inlet to improve the performance of the inlet at non-design Mach numbers. As the flight speed moves towards a higher Mach number, problems such as increased additional mass, complex structure, and reduced reliability become more prominent. Plasma, magnetic fluid (MHD) flow control technology is a new concept of active flow control technology, which exerts controllable disturbance on the flow field through the pressure and temperature changes caused by gas discharge, and controls the flow characteristics through the interaction between the electromagnetic field and the conductive fluid. . Compared with the traditional inlet flow control, it has the characteristics of no moving parts, fast response, wide excitation frequency and so on.

According to different control methods and mechanisms, the inlet shock control can be divided into two types: large-scale MHD flow control and boundary layer flow control based on surface plasma. Restricted by the development of non-equilibrium ionization technology and strong magnetic field generation technology, for large-size inlet MHD flow control, due to its low conductivity, low magnetic field, and high flow velocity, the action number will be low S=σB ² L/ρu , the control effect becomes worse. In comparison, the boundary layer flow control based on surface plasmons does not need to ionize a large volume of gas, and the velocity and density of the gas flow in the boundary layer are low, so it has a better control effect. However, the discharge plasma will move downstream with the air flow. When the moving distance exceeds the limit distance that can be maintained by the applied voltage, the discharge will be extinguished, and then the plasma will be re-formed, so continuous control cannot be implemented. The characteristics of the source are related to the flow field conditions.

Contents of the invention

Aiming at the shortcomings and deficiencies of the existing hypersonic inlet flow control technology, the present invention proposes an inlet shock wave control device and method based on surface magnetron arc discharge, so as to improve Performance at Mach number.

Technical scheme of the present invention is:

The inlet shock wave control device based on surface magnetron arc discharge is characterized in that it includes a discharge electrode and a permanent magnet;

The discharge electrode is two electrodes, which are installed in the head of the air inlet, and the end surface of the discharge electrode exposed outward is flush with the inner wall of the head of the air inlet; the two electrodes can withstand the applied pulse breakdown voltage. Arc discharge plasma is generated on the inner wall of the inlet duct, and the plasma is maintained under the action of a DC sustaining voltage lower than the pulse breakdown voltage;

The permanent magnet is installed in the inlet head, and the permanent magnet can generate a magnetic field perpendicular to the direction of the electric field, thereby generating a Lorentz force on the plasma in the direction of the reverse flow.

A further preferred solution, the said air inlet shock wave control device based on surface magnetron arc discharge is characterized in that: the discharge electrode is a cylindrical electrode, which is embedded in the head of the air inlet, and the cylindrical One end is exposed outwards and is flush with the inner wall surface of the air inlet head.

A further preferred solution, the inlet shock wave control device based on surface magnetron arc discharge, is characterized in that: a magnetic pole surface of the permanent magnet is parallel to the end face of the cylindrical discharge electrode, and the generated magnetic field is perpendicular to the end face of the cylindrical electrode .

A further preferred solution, the inlet shock wave control device based on surface magnetron arc discharge, is characterized in that: the magnetic pole surface of the permanent magnet parallel to the end surface of the cylindrical discharge electrode completely covers the cylindrical discharge electrode in the forward direction The end face of the discharge electrode; at the same time, the two discharge electrodes are completely covered in the direction of the air inlet perpendicular to the flow direction.

A further preferred solution, the above-mentioned inlet shock wave control device based on surface magnetron arc discharge, is characterized in that: two electrodes are respectively installed at the edge positions of the inlet head along the span direction of the inlet.

Using the above-mentioned device to carry out the inlet shock wave control method based on surface magnetron arc discharge is characterized in that: comprising the following steps:

Step 1: Install a cylindrical discharge electrode on both sides of the air inlet head along the span direction of the air inlet in a built-in manner, and one end of the cylinder is exposed outward and is flush with the inner wall of the air inlet head ;

Step 2: Install a permanent magnet in the head of the air inlet, one pole surface of the permanent magnet is parallel to the end face of the cylindrical discharge electrode, and the generated magnetic field is perpendicular to the end face of the cylindrical electrode; the permanent magnet is parallel to the magnetic pole surface of the end face of the cylindrical discharge electrode The end face of the cylindrical discharge electrode is completely covered in the direction of the incoming flow, and at the same time, the two discharge electrodes are completely covered in the direction of the air inlet perpendicular to the direction of the incoming flow;

Step 3: When the flight Mach number is greater than the design Mach number, control the discharge electrode to generate arc discharge plasma on the inner wall of the air inlet under the action of the applied pulse breakdown voltage, and under the action of a DC maintenance voltage lower than the pulse breakdown voltage Maintain the discharge plasma; the shock angle is increased by the thermal effect of the discharge plasma, and under the action of the magnetic field, the Lorentz force in the reverse direction of the flow is generated to decelerate the airflow and constrain the discharge plasma, so that the shock wave of the inlet port intersects the intake air Road lip; different degrees of control can be achieved by varying the DC sustain voltage.

Beneficial effect

The advantages of the present invention are: the combined discharge mode of high voltage pulse breakdown-low voltage DC maintenance can effectively improve the conductivity of the arc plasma, improve the discharge intensity and increase the discharge power; preferably adopting cylindrical electrodes can increase the uniformity of the discharge Degree; the generation of the magnetic field uses permanent magnets, which have the advantages of light weight, small size, and uniform and stable magnetic field generation; the application of a magnetic field can generate a Lorentz force in the direction of the reverse flow to decelerate the airflow and confine the discharge plasma to enhance the control effect.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and comprehensible from the description of the embodiments in conjunction with the following drawings, wherein:

Figure 1: A schematic diagram of an inlet shock wave control device and method based on surface magnetron arc discharge;

Among them: (a): three-dimensional schematic diagram; (b): XY plane schematic diagram; (c): YZ plane schematic diagram.

1. Discharge electrode; 2. Permanent magnet; 3. Plasma generation area; 4. Surface of permanent magnet poles.

detailed description

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Orientation indicated by rear, left, right, vertical, horizontal, top, bottom, inside, outside, clockwise, counterclockwise, etc. The positional relationship is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, Therefore, it should not be construed as limiting the invention.

The inlet shock wave control device and method based on the surface magnetron arc discharge proposed by the present invention mainly include plasma and magnetic field generation methods and shock wave control methods.

As shown in FIG. 1 , the inlet shock wave control device based on surface magnetron arc discharge in this embodiment includes discharge electrodes and permanent magnets.

Plasma generation is to generate arc discharge plasma on the inner wall of the inlet port through the discharge electrode using a combination discharge method of high voltage pulse breakdown and low voltage DC maintenance. The discharge electrodes are two cylindrical electrodes, which are embedded in the inlet head, and one end of the cylinder is exposed to the outside and is flush with the inner wall of the inlet head, so as not to disturb the flow field of the inlet. make an impact. The two discharge electrodes are respectively installed on the edge of the intake duct head along the span direction of the intake duct (that is, the Y direction in the figure). The two electrodes can generate arc discharge plasma on the inner wall of the air inlet under the action of the applied pulse breakdown voltage, and maintain the plasma under the action of a DC sustaining voltage lower than the pulse breakdown voltage; the pulse breakdown in this embodiment The voltage is 6000-10000V, and the DC maintenance voltage is 1000-3000V.

And the generation of magnetic field is realized by permanent magnet, and described permanent magnet is installed in the inlet head, and the magnetic pole surface of permanent magnet is parallel to the end face of cylindrical discharge electrode, and the magnetic field that produces is perpendicular to cylindrical electrode end face; Permanent magnet is parallel The magnetic pole surface on the end face of the cylindrical discharge electrode completely covers the end face of the cylindrical discharge electrode in the forward flow direction; at the same time, it completely covers the two discharge electrodes in the direction of the air inlet perpendicular to the incoming flow direction. In this embodiment, the magnetic field strength is 0.3-1.0T, and the permanent magnet generates a magnetic field perpendicular to the direction of the electric field, thereby generating a Lorentz force on the plasma in the direction of the reverse flow.

When the flight Mach number is greater than the design Mach number, the discharge electrode is controlled to generate arc discharge plasma on the inner wall of the air inlet under the action of the applied pulse breakdown voltage, and maintain the discharge plasma under the action of a DC sustaining voltage lower than the pulse breakdown voltage body; through the thermal effect of the discharge plasma, the shock angle is increased, and under the action of the magnetic field, a Lorentz force in the direction of the reverse flow is generated to decelerate the air flow and confine the discharge plasma, so that the inlet shock wave intersects the inlet lip At the same time, different control levels can be achieved by changing the DC maintenance voltage.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be construed as limitations to the present invention. Variations, modifications, substitutions, and modifications to the above-described embodiments are possible within the scope of the present invention.

Claims (6)

1. An inlet shock wave control device based on surface magnetron arc discharge, characterized in that: comprising discharge electrodes and permanent magnets; The discharge electrode is two electrodes, which are installed in the head of the air inlet, and the end surface of the discharge electrode exposed outward is flush with the inner wall of the head of the air inlet; the two electrodes can withstand the applied pulse breakdown voltage. Arc discharge plasma is generated on the inner wall of the inlet duct, and the plasma is maintained under the action of a DC sustaining voltage lower than the pulse breakdown voltage; The permanent magnet is installed in the inlet head, and the permanent magnet can generate a magnetic field perpendicular to the direction of the electric field, thereby generating a Lorentz force on the plasma in the direction of the reverse flow. 2. A shock wave control device based on surface magnetron arc discharge according to claim 1, characterized in that: the discharge electrode is a cylindrical electrode, which is embedded in the head of the inlet, and One end of the cylinder is exposed outwards and is flush with the inner wall of the head of the air inlet. 3. A kind of intake shock control device based on surface magnetron arc discharge according to claim 2, characterized in that: a magnetic pole surface of the permanent magnet is parallel to the end face of the cylindrical discharge electrode, and the magnetic field produced is perpendicular to the cylindrical electrode end face. 4. A kind of inlet shock wave control device based on surface magnetron arc discharge according to claim 3, characterized in that: the magnetic pole surface of the permanent magnet parallel to the end face of the cylindrical discharge electrode completely covers the cylinder in the forward flow direction The end face of the shaped discharge electrode; at the same time, the two discharge electrodes are completely covered in the direction of the air inlet perpendicular to the flow direction. 5. According to claim 1 or 4, an inlet shock wave control device based on surface magnetron arc discharge is characterized in that: two electrodes are respectively installed on the edge of the inlet head along the span direction of the inlet Location. 6. utilize the described device of claim 5 to carry out the inlet shock wave control method based on surface magnetron arc discharge, it is characterized in that: comprise the following steps: Step 1: Install a cylindrical discharge electrode on both sides of the air inlet head along the span direction of the air inlet in a built-in manner, and one end of the cylinder is exposed outward and is flush with the inner wall of the air inlet head ; Step 2: Install a permanent magnet in the head of the air inlet, one pole surface of the permanent magnet is parallel to the end face of the cylindrical discharge electrode, and the generated magnetic field is perpendicular to the end face of the cylindrical electrode; the permanent magnet is parallel to the magnetic pole surface of the end face of the cylindrical discharge electrode The end face of the cylindrical discharge electrode is completely covered in the direction of the incoming flow, and at the same time, the two discharge electrodes are completely covered in the direction of the air inlet perpendicular to the direction of the incoming flow; Step 3: When the flight Mach number is greater than the design Mach number, control the discharge electrode to generate arc discharge plasma on the inner wall of the air inlet under the action of the applied pulse breakdown voltage, and under the action of a DC maintenance voltage lower than the pulse breakdown voltage Maintain the discharge plasma; the shock angle is increased by the thermal effect of the discharge plasma, and under the action of the magnetic field, the Lorentz force in the reverse direction of the flow is generated to decelerate the airflow and constrain the discharge plasma, so that the shock wave of the inlet port intersects the intake air Road lip; different degrees of control can be achieved by varying the DC sustain voltage.