Space-time controllable electric excitation device for axisymmetric combustion chamber and regulation and control method

Abstract

The invention relates to a space-time controllable electric excitation device for an axisymmetric combustion chamber and a regulation and control method. The device comprises an axisymmetric combustion chamber, two or more electrode needles are arranged on the two sides of the axisymmetric combustion chamber respectively based on the central axis of the axisymmetric combustion chamber, the electrode needles on one side serve as a positive electrode set, and the electrode needles on the other side serve as a negative electrode set; a high-voltage power supply is also arranged and is connected with the change-over switch; and the change-over switch can be respectively switched on the electrode needles of the positive electrode group and the electrode needles of the negative electrode group so as to change a conduction path between the positive electrode group and the negative electrode group.

Description

Technical Field

[0001] The present invention relates to the technical field of combustion control, and in particular to a time-space controllable electric excitation device and a control method for an axisymmetric combustion chamber. Background Art

[0002] Plasma-assisted combustion technology, a key means of enhancing the combustion process, has been extensively studied in recent years in high-speed combustion systems such as scramjets. This technology generates a non-equilibrium plasma through high-voltage discharge, enhancing local ignition energy and improving combustion stability. It holds significant potential, particularly under extreme operating conditions (e.g., near the lean / rich burn limit and across a wide Mach number range).

[0003] Traditional plasma-assisted combustion schemes primarily include fuel-assisted flame stabilization, spark plug plasma flame stabilization, and flow field structure optimization. The fuel-assisted flame stabilization scheme involves injecting flammable gaseous fuels such as hydrogen to form a localized flame within the combustion chamber, igniting the mainstream combustible mixture. Spark plug discharge schemes generate thermal equilibrium plasma through high-voltage pulses to increase the temperature and concentration of active species. Flow field structure optimization primarily involves designing an annular cavity within an axisymmetric combustion chamber, extending the fuel residence time through a low-speed recirculation zone. In recent years, there have also been developments based on axisymmetric combustion chambers.

[0004] However, in traditional plasma-assisted combustion schemes, the discharge timing and discharge path are usually difficult to accurately control simultaneously during the discharge process. This causes the randomness of the electric excitation system in time and space, resulting in the inability to accurately perform instant and targeted combustion control according to the combustion state during the electric excitation combustion control process. Summary of the Invention

[0005] Based on this, it is necessary to provide a time-space controllable electrical excitation device and control method for an axisymmetric combustion chamber that can solve the problem that the discharge moment and discharge path are difficult to accurately control at the same time in order to solve the above technical problems.

[0006] A spatiotemporally controllable electric excitation device for an axisymmetric combustion chamber, comprising an axisymmetric combustion chamber, wherein two or more electrode needles are respectively arranged on both sides of a central axis of the axisymmetric combustion chamber, wherein the electrode needles on one side serve as a positive electrode group and the electrode needles on the other side serve as a negative electrode group; A high-voltage power supply is also provided, and the high-voltage power supply is connected to a switching switch; the switching switch can be switched on the electrode needles of the positive electrode group and the electrode needles of the negative electrode group respectively to change the conduction path between the positive electrode group and the negative electrode group.

[0007] A control method, characterized by adopting the spatiotemporal controllable electric excitation device for an axisymmetric combustion chamber; When plasma combustion is required, the conduction path is determined according to the target combustion area, and then the electrode needles in the positive electrode group and the negative electrode group are selected according to the conduction path, and the selected electrode needles are connected to the high-voltage power supply circuit by switching the switch; The high-voltage power supply provides high voltage electricity and transmits it to the selected electrode needle via a switching switch; when the high voltage electricity exceeds the breakdown threshold of the distance between the two electrodes, a discharge channel is formed through the combustion chamber, generating plasma to enhance combustion; When entering the non-steady-state combustion condition, the pairing connection state of the electrode needles in the positive electrode group and the negative electrode group is changed by switching the switch, thereby changing the spatial position of the plasma and realizing dynamic directional control of the combustion field.

[0008] Compared with the prior art, the spatiotemporal controllable electric excitation device and control method for an axisymmetric combustion chamber provided by the present invention has the following effects: 1. Two or more electrode needles are set on each of the electrode groups on both sides. Different electrode needles in the positive electrode group and the negative electrode group can be connected by switching switches to achieve multiple groups of electrode pairing to cope with different spatial positions in the combustion chamber. This allows the plasma discharge channel to be directionally triggered to specific areas upstream, downstream or circumferentially in the combustion chamber, accurately acting on key positions such as the flame stabilization zone and the combustion reaction zone.

[0009] 2. The switching switch can quickly switch the conduction path. Under non-steady-state conditions, it can adjust the spatial position of the plasma and the direction of energy injection in real time, realizing directional combustion control during non-steady-state combustion. Both the discharge time and the discharge path can be controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0011] Figure 1 Schematic diagram of the structure of a spatiotemporal controllable electric excitation device for an axisymmetric combustion chamber in one embodiment.

[0012] Description of reference numerals: Axisymmetrical combustion chamber 1, electrode needle 2, high voltage power supply 3, switch 4, arc 5.

[0013] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0014] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0015] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship and movement status of various components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0016] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referenced. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0017] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; it can mean mechanical connection, electrical connection, physical connection, or wireless communication connection; it can mean direct connection or indirect connection through an intermediate medium; it can mean internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0018] It can be understood that the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0019] The following describes the implementation of the present invention in detail with reference to the accompanying drawings in the embodiments of the present invention.

[0020] Example 1 like Figure 1As shown, the spatiotemporal controllable electric excitation device for an axisymmetric combustion chamber provided in this embodiment includes an axisymmetric combustion chamber 1. Based on the central axis of the axisymmetric combustion chamber 1, two or more electrode needles 2 are respectively arranged on both sides, wherein the electrode needles 2 on one side serve as a positive electrode group, and the electrode needles 2 on the other side serve as a negative electrode group; a high-voltage power supply 3 is also provided, and the high-voltage power supply 3 is connected to a switching switch 4; the switching switch 4 can be switched on the electrode needles 2 of the positive electrode group and the electrode needles 2 of the negative electrode group respectively to change the conduction path between the positive electrode group and the negative electrode group.

[0021] Specifically, the axisymmetric combustion chamber 1 is made of an insulating material. This provides insulation after the electrode needles 2 are inserted, preventing current from conducting between the electrode needles 2 through the combustion chamber. The insulating material used to make the axisymmetric combustion chamber 1 needs to possess properties such as high temperature resistance, excellent insulation, strong chemical stability, and high structural strength. These materials include, but are not limited to, ceramics, quartz glass, and their composites. The specific choice can be made based on the specific situation. For example, if easy observation is required, the axisymmetric combustion chamber 1 can be made of quartz glass. If both observation requirements and special performance requirements are required, the axisymmetric combustion chamber 1 can also be made of half quartz glass and the other half ceramic.

[0022] The electrode needles 2 are respectively arranged on both sides with the central axis of the axisymmetric combustion chamber 1 as the reference, with more than two electrode needles 2 on each side. The number of electrode needles 2 on both sides can be equal or unequal, and is determined according to the actual space size and needs. The electrode needles 2 on one side are used as the positive electrode group, and the electrode needles 2 on the other side are used as the negative electrode group. The positive electrode group and the negative electrode group can be symmetrically arranged or asymmetrically arranged with the central axis as the reference. In this embodiment, taking into account factors such as mechanical balance, electric field uniformity and functional symmetry, such as Figure 1 As shown, the positive electrode group and the negative electrode group are preferably symmetrically arranged with the central axis as the reference, the electrode needle 2 of the positive electrode group is located in the left semicircle of the axisymmetric combustion chamber 1, and the electrode needle 2 of the negative electrode group is located in the right semicircle of the axisymmetric combustion chamber 1, and three electrode needles 2 are arranged in each group.

[0023] Electrode needle 2 is inserted into the wall of the axisymmetric combustion chamber 1, with one end located inside the combustion chamber and the other end located outside. Electrode needle 2 has a diameter of approximately 1-2 mm, and its length is determined based on actual needs to ensure that after insertion into the axisymmetric combustion chamber 1, its external end can smoothly connect to the switch 4. Electrode needle 2 is typically made of metal, such as tungsten, copper, or silver.

[0024] like Figure 1As shown, a schematic cross-section of an axisymmetric combustion chamber 1 is provided in this embodiment. It can be seen that the cross-section of the axisymmetric combustion chamber 1 is circular. In the positive electrode group and the negative electrode group, when the electrode needle 2 is inserted into the axisymmetric combustion chamber 1, each electrode needle 2 can be arranged in parallel, or can be inserted into the wall of the axisymmetric combustion chamber 1 at any angle. When arranged in parallel, the axis directions of each electrode needle 2 are consistent; when inserted at any angle, the insertion angle is the angle between the axis of the electrode needle 2 and the normal of the wall at the insertion point, and the angle range is 0° to 60°. For example, when the insertion angle is equal to 0°, the electrode needle 2 is inserted in the radial direction; when the insertion angle is greater than 0° and less than or equal to 60°, an angle is formed between the electrode needle 2 and the radius, and its spatial posture is tilted relative to the radial direction.

[0025] In addition, under the arbitrary angle insertion mode, under the premise of ensuring no spatial interference, the angular relationship between the electrode needles 2 is not restricted and can be the same or different; the distribution mode is also not restricted and can be distributed with equal or unequal spacing.

[0026] There are two switches 4, one on the positive electrode group side and the other on the negative electrode group side. The switch 4 on the positive electrode group side switches the connection between the electrode pins 2 in the positive electrode group; the switch 4 on the negative electrode group side switches the connection between the electrode pins 2 in the negative electrode group.

[0027] The switching switch 4 is a single-pole multi-position controllable switch. It can use multiple relays or be precisely controlled by a semiconductor switch to isolate the low-voltage control circuit and the high-voltage discharge circuit. There is no risk of short circuit. In addition, multiple single-pole multi-position switches can be directly stacked to give the device an extremely high control margin. The present invention separates the high-voltage circuit where the arc occurs and the low-voltage control circuit that controls the discharge by switching the switch 4, avoiding the risk of mutual interference and short circuit between the high and low voltage circuits. The use of the switching switch 4 has a fast response speed, and the high and low voltage circuits are isolated and have good anti-interference ability. During actual installation, the switching switch 4 with appropriate parameters can be selected according to the cable arrangement, the parameters of the high-voltage power supply 3 and the spatial distribution. It is worth noting that regardless of whether the number or layout of the electrode needles 2 in the positive electrode group and the negative electrode group are symmetrical, the switching switch 4 can achieve switching control.

[0028] A high-voltage power supply 3 is located outside the axisymmetric combustion chamber 1 and is connected to two switches 4 via wires. When a conduction path is required, the two switches 4 are connected to one of the electrode pins 2 in the positive and negative electrode groups, respectively. The high-voltage power supply 3 then provides voltage, forming an arc 5 between the two electrode pins connected to the switches 4.

[0029] It is worth noting that the voltage provided by the high-voltage power supply 3 must be greater than or equal to the breakdown threshold between the positive and negative electrode groups. Specifically, the voltage provided by the high-voltage power supply 3 must be greater than or equal to the breakdown threshold of the maximum electrode spacing. In this embodiment, the maximum electrode spacing within the axisymmetric combustion chamber is equal to the combustion chamber's inner diameter, and the breakdown threshold is approximately 300-1000 V / mm.

[0030] In this embodiment, the electrode needles 2 in the positive and negative electrode groups are each connected to a high-voltage power supply 3 via a switch 4. The high-voltage power supply 3 provides high voltage electricity capable of breaking down the gas medium between the electrodes. By controlling the switch 4, any two electrode needles 2 in the positive and negative electrode groups can be connected to the high-voltage circuit. When the high voltage across the electrode needles 2 exceeds the breakdown threshold of the gas in the combustion chamber, a breakdown discharge can be generated along the conductive path. This allows for a breakdown discharge that penetrates the axisymmetric combustion chamber 1, enabling targeted combustion control during the unsteady-state combustion process.

[0031] The conduction path refers to the discharge path when any two electrode needles 2 in the positive electrode group and the negative electrode group form an arc 5 due to breakdown discharge. It can be understood that when the electrode needles 2 are fixed in the axisymmetric combustion chamber 1, their positions are determined. Since gas breakdown usually chooses the path that is easiest to break down for discharge, the arc 5 is often generated between relatively short electrode needle spacings, thereby achieving controllable conduction path. It should be noted that discharge under natural conditions does not strictly occur along the shortest breakdown distance (i.e., a straight line connecting two points). Although its path is approximately a straight line, it may bend at certain locations. Therefore, the conduction path can only be roughly controlled.

[0032] In addition, by switching the switch 4 to perform precise circuit control, breakdown discharge can be formed at the moment the switch 4 connects the circuit, thereby achieving precise control of the discharge time.

[0033] Compared with the traditional electric excitation scheme that only acts on the wall of the combustion chamber, the present invention can realize discharge throughout the combustion chamber, significantly increasing the range of action, greatly increasing the interaction time and space with the mainstream flame in the combustion chamber, and significantly improving the electric excitation combustion control of the mainstream flame combustion effect.

[0034] By switching the switch to connect different electrode needles in the positive electrode group and the negative electrode group, multiple groups of electrode pairing can be achieved to cope with different spatial positions in the combustion chamber, so that the plasma discharge channel can be triggered in a directionally directed manner to specific areas upstream, downstream or circumferentially of the combustion chamber, and accurately act on key positions such as the flame stabilization zone and the combustion reaction zone.

[0035] The switch rapidly switches the conduction path, enabling real-time adjustment of the plasma's spatial position and energy injection direction during unsteady-state conditions, enabling directional combustion control during unsteady-state combustion. Furthermore, the invention simultaneously controls both discharge time and conduction path, facilitating the development of more precise electrically excited combustion control strategies.

[0036] Example 2 Based on the spatiotemporal controllable electric excitation device for an axisymmetric combustion chamber in Example 1, this embodiment discloses a control method, including: When plasma combustion is required, the conduction path is determined according to the target combustion area, and then the electrode needles in the positive electrode group and the negative electrode group are selected according to the conduction path, and the selected electrode needles are connected to the high-voltage power supply circuit by switching the switch.

[0037] The high-voltage power supply provides high voltage electricity and transmits it to the selected electrode needle through a switching switch; when the high voltage electricity exceeds the breakdown threshold of the distance between the two electrodes, a discharge channel is formed through the combustion chamber, generating plasma to enhance combustion.

[0038] When entering the non-steady-state combustion condition, the pairing connection state of the electrode needles in the positive electrode group and the negative electrode group is changed by switching the switch, thereby changing the spatial position of the plasma and realizing dynamic directional control of the combustion field.

[0039] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0040] The above-described embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that a person skilled in the art would be able to make numerous modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A spatiotemporally controllable electric excitation device for an axisymmetric combustion chamber, comprising an axisymmetric combustion chamber, characterized in that: Based on the central axis of the axisymmetric combustion chamber, two or more electrode needles are respectively arranged on both sides, wherein the electrode needles on one side serve as a positive electrode group and the electrode needles on the other side serve as a negative electrode group; A high-voltage power supply is also provided, and the high-voltage power supply is connected to a switching switch; the switching switch can be switched on the electrode needles of the positive electrode group and the electrode needles of the negative electrode group respectively to change the conduction path between the positive electrode group and the negative electrode group.

2. The spatiotemporally controllable electric excitation device for an axisymmetric combustion chamber according to claim 1, characterized in that: The axisymmetric combustion chamber is made of insulating material.

3. The spatiotemporally controllable electric excitation device for an axisymmetric combustion chamber according to claim 2, characterized in that: The insulating material includes but is not limited to ceramics, quartz glass and composite materials thereof.

4. The spatiotemporally controllable electric excitation device for an axisymmetric combustion chamber according to claim 1, characterized in that: The positive electrode group and the negative electrode group are symmetrically arranged with respect to the central axis.

5. The spatiotemporally controllable electric excitation device for an axisymmetric combustion chamber according to claim 4, characterized in that: In the positive electrode group and the negative electrode group, the electrode needles are arranged in parallel.

6. The spatiotemporally controllable electric excitation device for an axisymmetric combustion chamber according to claim 4, characterized in that: In the positive electrode group and the negative electrode group, each electrode needle is inserted into the wall surface of the axisymmetric combustion chamber along an arbitrary angle.

7. The spatiotemporally controllable electric excitation device for an axisymmetric combustion chamber according to claim 5 or 6, characterized in that: The electrode needle is made of metal material.

8. The spatiotemporally controllable electric excitation device for an axisymmetric combustion chamber according to claim 1, characterized in that: The voltage provided by the high-voltage power supply is greater than or equal to a breakdown threshold between the positive electrode group and the negative electrode group.

9. The spatiotemporally controllable electric excitation device for an axisymmetric combustion chamber according to claim 1, characterized in that: The switching switch adopts a plurality of relays or semiconductor switches.

10. A control method, characterized in that: A spatiotemporally controllable electric excitation device for an axisymmetric combustion chamber according to any one of claims 1 to 9; When plasma combustion is required, the conduction path is determined according to the target combustion area, and then the electrode needles in the positive electrode group and the negative electrode group are selected according to the conduction path, and the selected electrode needles are connected to the high-voltage power supply circuit by switching the switch; The high-voltage power supply provides high voltage electricity and transmits it to the selected electrode needle via a switching switch; when the high voltage electricity exceeds the breakdown threshold of the distance between the two electrodes, a discharge channel is formed through the combustion chamber, generating plasma to enhance combustion; When entering the non-steady-state combustion condition, the pairing connection state of the electrode needles in the positive electrode group and the negative electrode group is changed by switching the switch, thereby changing the spatial position of the plasma and realizing dynamic directional control of the combustion field.

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