Externally-attached multifunctional plasma flame stabilizer

Abstract

The invention provides an externally-attached multifunctional plasma flame stabilizer, and relates to the technical field of plasma ignition combustion supporting. Comprising an evaporative flame stabilizer and an externally-attached exciter. The evaporative flame stabilizer is provided with a combustion area defined by apron boards, and the apron boards are provided with notches penetrating through the inside and the outside. And the externally attached exciter is embedded into the notch. According to the design, on the premise that the aerodynamic shape and the internal flow field of the flame stabilizer are not changed, high integration of the ignition function and the flame stabilizing function is achieved, occupation of the combustion area space and interference of main airflow are avoided, and the device compactness and the engineering applicability are improved. A gliding arc discharge plasma exciter is adopted, non-equilibrium plasmas can be generated under the atmospheric pressure and act on a backflow area, ignition reliability is enhanced, fuel atomization and evaporation are promoted, the ignition boundary is expanded, flame quenching is restrained, the device is suitable for poor working conditions such as low equivalence ratio, low temperature, low pressure or high flow speed, and jump from passive flame stabilization to active intensified combustion is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plasma ignition and combustion, and particularly relates to an external multifunctional plasma flame stabilizer. BACKGROUND

[0002] In the field of high-speed airflow combustion applications such as aerospace, gas turbines and ramjet engines, a flame stabilizer is a key component for realizing fuel ignition and maintaining stable combustion of a flame. Traditional flame stabilizers (such as V-shaped grooves, evaporation tube stabilizers, etc.) mainly form a recirculation zone through mechanical structures, and use high-temperature combustion recirculation to heat the mixed gas, thereby realizing ignition and flame anchoring. However, such traditional devices are relatively single in the ignition function, and only rely on an initial ignition source (such as a spark plug) to complete the ignition process, lack active intervention and continuous excitation capability, resulting in poor ignition reliability, long ignition delay and insufficient combustion stability under adverse conditions such as low equivalence ratio, low temperature, low pressure or high flow rate.

[0003] Especially in systems using liquid fuel (such as kerosene), the quality of fuel atomization directly affects the combustion efficiency and ignition success rate. The traditional ignition method is difficult to effectively break up large-diameter liquid droplets, resulting in insufficient evaporation of fuel oil, uneven formation of combustible mixture, and thus limiting the expansion of the ignition boundary, and even causing ignition failure or flame blowout. In addition, the traditional ignition device is usually an external and independently installed component (such as a spark plug or a vortex stabilizer), which has low integration with the flame stabilizer body, occupies a large space, and has a limited excitation range, which cannot effectively regulate the thermochemistry of the entire recirculation zone, limiting its application prospect in compact combustion chambers.

[0004] In recent years, plasma-assisted combustion technology has attracted widespread attention due to its non-equilibrium characteristics, fast response capability and strong chemical activity excitation capability. Among them, sliding arc discharge plasma can generate a large volume of non-equilibrium plasma at atmospheric pressure, accompanied by significant thermal effects and free radical generation capability, and is considered as a highly potential combustion intensification means. Existing research attempts to arrange a plasma generator in the combustion chamber for improving the ignition performance. However, most of the schemes still adopt an embedded design, which needs to make great changes to the original structure of the flame stabilizer, and even the flame stabilizer will occupy the internal space of the combustion chamber, increasing the complexity of manufacturing and maintenance. Moreover, the installation position and structure design of the embedded exciter may have an adverse effect on the airflow distribution of the combustion chamber, reducing the combustion efficiency. SUMMARY

[0005] The present application aims to provide an external multifunctional plasma flame stabilizer to alleviate the technical problem that the exciter of the prior art occupies the internal space of the combustion chamber, increasing the complexity of manufacturing and maintenance.

[0006] In a first aspect, the externally attached multifunctional plasma flame stabilizer provided by the present invention includes: an evaporative flame stabilizer and an externally attached actuator; The evaporative flame stabilizer has a combustion zone formed by a skirt, and the skirt has a through slot. The external actuator is embedded in the slot.

[0007] In conjunction with the first aspect, the present invention provides a first possible implementation of the first aspect, wherein the external actuator comprises: a ceramic substrate, an anode, a cathode, and a plurality of metal sliding arc rails; The ceramic substrate is embedded in the slot, and the anode, a plurality of the metal sliding arc rails and the cathode are arranged in sequence at intervals and respectively mounted on the ceramic substrate.

[0008] In conjunction with the first possible implementation of the first aspect, the present invention provides a second possible implementation of the first aspect, wherein the ceramic substrate is provided with embedded grooves respectively adapted to the anode, a plurality of the metal sliding arc slide rails and the cathode.

[0009] In conjunction with the first possible implementation of the first aspect, the present invention provides a third possible implementation of the first aspect, wherein the cathode includes: a first extension and a second extension; The first extension extends along the x-direction perpendicular to the air intake direction, and the second extension is connected to one end of the first extension near the metal sliding arc rail and is inclined in a direction away from the metal sliding arc rail.

[0010] In conjunction with the third possible implementation of the first aspect, the present invention provides a fourth possible implementation of the first aspect, wherein the metal sliding arc slide rail includes: a straight portion, a first trapezoidal side portion, and a second trapezoidal side portion; The straight portion is parallel to the first extension portion, and the straight portion is connected between the first trapezoidal side portion and the second trapezoidal side portion; The first trapezoidal side and the second trapezoidal side each form an angle greater than 90 degrees with the straight portion.

[0011] In conjunction with the fourth possible implementation of the first aspect, the present invention provides a fifth possible implementation of the first aspect, wherein the first trapezoidal side portion and the second trapezoidal side portion are connected to the straight portion at one end near the opening of the combustion region, and extend into the combustion region respectively.

[0012] In conjunction with the first aspect, the present invention provides a sixth possible implementation of the first aspect, wherein the two opposing skirt plates are respectively provided with the slots, and the external actuators are respectively installed in the two opposing slots.

[0013] In conjunction with the first aspect, the present invention provides a seventh possible implementation of the first aspect, wherein the evaporative flame stabilizer has a mixing chamber and a partition is installed between the mixing chamber and the combustion zone; The partition plate is provided with multiple dispersion holes, which are spaced apart.

[0014] In conjunction with the seventh possible implementation of the first aspect, the present invention provides an eighth possible implementation of the first aspect, wherein the evaporative flame stabilizer is provided with an air inlet, and the mixing chamber is located between the air inlet and the partition.

[0015] In conjunction with the eighth possible implementation of the first aspect, the present invention provides a ninth possible implementation of the first aspect, wherein the evaporative flame stabilizer is equipped with an oil injection device, the oil injection device being inserted into the air inlet.

[0016] The embodiments of this invention bring the following beneficial effects: By embedding an external exciter into a slot on the skirt of the evaporative flame stabilizer, a high degree of integration between the ignition function and the flame stabilization structure is achieved. This design introduces the plasma excitation unit externally without altering the aerodynamic shape and internal flow field of the flame stabilizer, avoiding the space occupation of the combustion chamber and interference with the mainstream airflow inherent in traditional embedded devices, significantly improving the compactness and engineering applicability of the device. Especially in space-constrained applications such as aerospace and scramjet engines, this structure effectively solves the technical challenges of complex installation and impact on flow field organization inherent in traditional plasma-assisted combustion devices.

[0017] Furthermore, this technical solution uses a sliding arc discharge plasma generator as an external exciter, which can generate non-equilibrium plasma with both thermal and chemical reactivity under atmospheric pressure. This plasma directly acts on the recirculation zone formed by the flame stabilizer, enhancing not only the reliability of initial ignition but also the ability to actively control the combustion process. Compared to traditional ignition methods that rely solely on spark plugs, this solution more effectively promotes the atomization, fragmentation, and evaporation mixing of liquid fuels (such as kerosene), improving the quality of the combustible mixture, expanding the ignition boundary, and suppressing flame quenching. It exhibits superior combustion stability and adaptability under harsh conditions such as low equivalence ratio, low temperature, low pressure, or high flow rate, achieving a functional leap from passive flame stabilization to active enhanced combustion.

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of the present invention, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 A schematic diagram of an externally attached multifunctional plasma flame stabilizer provided in an embodiment of the present invention; Figure 2 A schematic diagram of an evaporative flame stabilizer for an externally attached multifunctional plasma flame stabilizer provided in an embodiment of the present invention; Figure 3 A cross-sectional view of an evaporative flame stabilizer for an externally attached multifunctional plasma flame stabilizer provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the external actuator of the external multifunctional plasma flame stabilizer provided in an embodiment of the present invention.

[0021] Icons: 100-Evaporative flame stabilizer; 101-Combustion zone; 102-Mixing chamber; 110-Skirt; 120-Baffle; 130-Inlet port; 140-Fuel injection device; 200-External actuator; 210-Ceramic substrate; 220-Cathode; 221-First extension; 222-Second extension; 230-Anode; 240-Metal sliding arc rail; 241-Straight section; 242-First trapezoidal side section; 243-Second trapezoidal side section. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used only to describe differences in name and should not be construed as indicating or implying relative importance. Physical quantities in formulas, unless otherwise specified, should be understood as basic quantities in the International System of Units (SI), or derived quantities derived from basic quantities through mathematical operations such as multiplication, division, differentiation, or integration.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the externally attached multifunctional plasma flame stabilizer provided in this embodiment of the invention includes an evaporative flame stabilizer 100 and at least one external actuator 200. The evaporative flame stabilizer 100 is enclosed by annular or symmetrically arranged skirts 110 to form an internal space—that is, a combustion zone 101. The skirts 110 have slots extending inward and outward along the thickness direction on the circumferential or opposite sides. The size of these slots matches that of the external actuator 200 for embedding and installation. By embedding the external actuator 200 into these slots, the ignition function unit and the flame stabilization structure are integrated, avoiding the problems of traditional embedded plasma devices that require damage to the main combustion flow channel or occupation of space within the combustion chamber. High compactness and good engineering feasibility are achieved without altering the original aerodynamic shape and internal mainstream field organization of the evaporative flame stabilizer.

[0026] Furthermore, the external actuator 200 is located entirely within or flush with the outer contour of the combustion zone 101. Its front end face may protrude slightly from the skirt surface but not exceed the boundary of the core area of ​​the recirculation zone, thereby ensuring that it does not significantly interfere with the flow characteristics of the incoming gas, while effectively covering the plasma action area into the recirculation zone, thus improving ignition and flame stabilization efficiency.

[0027] likeFigure 1 and Figure 4 As shown, the external actuator 200 includes a ceramic substrate 210, a cathode 220, an anode 230, and several metal sliding arc rails 240. The ceramic substrate 210, serving as an insulating support, is made of a high-temperature resistant, high-dielectric-strength material (such as alumina Al2O3 or aluminum nitride AlN), exhibiting good thermal stability and mechanical strength. The entire actuator forms a sliding arc discharge structure by sequentially and periodically arranging and fixing the cathode 220, multiple metal sliding arc rails 240, and anode 230 onto the ceramic substrate 210.

[0028] When a high-voltage power supply is applied between the anode and cathode, the initial electric spark breaks down the air at the minimum distance to form a plasma channel. Subsequently, under the combined action of airflow shear force and electromagnetic Lorentz force, the electric arc "slides" along the slide rail away from the starting point, expanding into a large-volume non-equilibrium plasma jet, generating abundant active particles (such as O, H, OH free radicals), ultraviolet radiation, and local transient high temperatures (up to 2000–3000K), which are used to enhance fuel pyrolysis, promote free radical chain reactions, and improve the ignition performance of the mixed gas.

[0029] The ceramic substrate 210 has recessed grooves that are adapted to the cathode 220, each metal sliding arc rail 240, and the anode 230. These recessed grooves are rectangular or trapezoidal groove structures with a depth of about 70% to 90% of the thickness of the conductive components, so as to achieve semi-embedded installation of the conductive components.

[0030] This design improves the bonding strength between the electrode and the substrate, preventing detachment due to thermal expansion and contraction or vibration. It also reduces the overall profile height, minimizing the protrusion of the exciter within the slot and further reducing disturbance to the mainstream airflow. Furthermore, the embedded structure provides some electric field shielding, reducing the risk of surface flashover and improving discharge stability and lifespan.

[0031] Furthermore, the cathode 220 includes a first extension 221 and a second extension 222. The first extension 221 extends horizontally along the x-direction perpendicular to the air intake direction, forming the main current input terminal and the initial discharge trigger area. The second extension 222 is connected to the end of the first extension 221 near the metal sliding arc rail 240 and is inclined away from the rail (preferably with an inclination angle of 30° to 60°). This zigzag structure design can adjust the local electric field distribution, guiding the initial arc to preferentially form at a specific location and avoiding arcing concentrated at the edge, which could cause ablation.

[0032] More importantly, the tilted structure helps to extend the arc slip path, allowing the slip arc to develop and expand over a longer distance, generating a larger and more uniformly distributed plasma region, and enhancing its penetration ability and chemical activation effect into the mixed gas in the recirculation region.

[0033] See Figure 4 Each metal sliding arc rail 240 includes a straight portion 241, a first trapezoidal side portion 242, and a second trapezoidal side portion 243. The straight portion 241 is arranged parallel to the first extension portion 221 of the anode, forming the main channel for arc sliding. The first trapezoidal side portion 242 and the second trapezoidal side portion 243 are respectively connected to both sides of the straight portion 241, forming an overall trapezoidal outward expansion structure, and the included angle between the two side portions and the straight portion 241 is greater than 90 degrees (preferably 100° to 130°).

[0034] This trapezoidal structure can effectively widen the contact area at the root of the electric arc, reduce the current density, and reduce electrode burn-out; at the same time, it can expand the diffusion angle of the plasma plume, so that the generated active material can be injected more widely into the recirculation zone, improving the coverage of the combustible mixture at different locations.

[0035] The first trapezoidal side portion 242 and the second trapezoidal side portion 243 are connected to the straight portion 241 at one end near the opening of the combustion zone 101, and extend a certain length (e.g., 2 to 5 mm) from the connection point into the combustion zone 101.

[0036] This inward-extending design allows the plasma plume generated during the sliding arc discharge process to be directly injected into the near-wall recirculation zone of the combustion region 101, shortening the transport path of active species and significantly increasing their effective concentration in the critical combustion region. Especially under low-speed and low-temperature conditions, it can quickly establish a local high-temperature and high-activity environment, greatly shortening the ignition delay time and improving the ignition success rate under extreme conditions.

[0037] like Figure 1 , Figure 2 and Figure 3 As shown, slots are made on two opposing skirt plates 110, and an external actuator 200 is installed in each slot. In the actuator in one slot, the cathode 220, several metal sliding arc rails 240, and anode 230 are arranged sequentially along the x-direction; while in the actuator in the opposite slot on the other side, the actuators are arranged in reverse, that is, the cathode 220, several metal sliding arc rails 240, and anode 230 are arranged sequentially in the opposite x-direction (or the electrode polarities are equivalently exchanged).

[0038] This symmetrical, reverse arrangement can simultaneously excite sliding arc plasma on both sides, causing the two plasma jets to converge towards the center, forming a cross-excitation field. This not only enhances the free radical concentration and thermal energy density in the central region but also helps to break the airflow symmetry, induce local vortex structures, promote turbulent mixing of fuel and air, and further improve combustion stability and resistance to disturbances.

[0039] Furthermore, the evaporative flame stabilizer 100 includes a mixing chamber 102, which is separated from the combustion zone 101 by a partition 120. The partition 120 is a perforated plate structure with multiple dispersion holes arranged in an array or staggered pattern. The hole diameter is generally 0.5-3 mm, and the open area ratio is controlled between 20% and 50%. The premixed gas from the mixing chamber 102 is throttled and accelerated through these dispersion holes before being injected into the combustion zone 101, forming a high-speed jet that is strongly mixed with the returning high-temperature combustion gas, which is beneficial for establishing a stable ignition core and flame anchoring zone.

[0040] At the same time, the baffle can also play a role in equalizing pressure and stabilizing flow, preventing combustion oscillations from propagating upstream and improving the dynamic stability of the overall combustion system.

[0041] Furthermore, the evaporative flame stabilizer 100 is provided with an air inlet 130 through which external air or oxidizer enters the system. The mixing chamber 102 is located between the air inlet 130 and the baffle 120, forming a space for the initial mixing of fuel and air.

[0042] Air flows in through the intake port 130 and first enters the mixing chamber 102, where it undergoes primary mixing with the liquid fuel atomized from the fuel injection device 140. Because the mixing chamber is located in a low-velocity region, it is beneficial to prolong the residence time, promote fuel evaporation and homogenization, and form a high-quality combustible mixture, laying the foundation for subsequent efficient combustion.

[0043] This compact layout facilitates integration into small combustion devices and is suitable for space-constrained scenarios such as aerospace propulsion systems.

[0044] Furthermore, the evaporative flame stabilizer 100 also integrates a fuel injection device 140, which extends into the mixing chamber 102 through the air intake port 130 in an insert manner. The fuel injection device 140 can be in the form of a pressure atomizing nozzle, an air-assisted atomizer, or an ultrasonic nozzle, etc., and its outlet is oriented towards the center of the mixing chamber 102 or inclined at a specific angle to optimize the fuel spray pattern and air entrainment effect. By precisely controlling the fuel injection pressure, flow rate, and timing, flexible adjustment of the equivalence ratio can be achieved to adapt to different operating conditions.

[0045] In particular, in this invention, the sliding arc plasma generated by the external actuator 200 can help break up large-diameter oil droplets that have not been completely evaporated through thermal effects and free radical bombardment, significantly improving fuel atomization quality and evaporation rate, thereby overcoming the ignition failure problem caused by poor atomization under traditional ignition methods.

[0046] The externally attached multifunctional plasma flame stabilizer provided by this invention integrates a sliding arc discharge plasma exciter into the skirt slot of an evaporative flame stabilizer via an external embedding method, achieving a high degree of integration of ignition, flame stabilization, and combustion enhancement functions. This device requires no modification to the main combustion chamber structure, does not affect the mainstream flow field, and possesses advantages such as easy installation, rapid response, wide excitation range, and strong adaptability.

[0047] In practical applications, it is particularly suitable for high-speed airflow combustion systems using liquid fuels (such as aviation kerosene), such as ramjet engines, gas turbine afterburners, and high-altitude UAV power units. Even in harsh environments such as low pressure, low temperature, low stoichiometry, or high inflow velocity, it maintains excellent ignition reliability and combustion stability, truly achieving a technological leap from passive flame stabilization to active enhanced combustion.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An externally attached multifunctional plasma flame stabilizer, characterized in that, include: Evaporative flame stabilizer (100) and external actuator (200); The evaporative flame stabilizer (100) has a combustion zone (101) enclosed by a skirt (110), the skirt (110) having through slots inside and out; The external actuator (200) is embedded in the slot.

2. The externally attached multifunctional plasma flame stabilizer according to claim 1, characterized in that, The external actuator (200) includes: a ceramic substrate (210), an anode (230), a cathode (220), and several metal sliding arc rails (240). The ceramic substrate (210) is embedded in the slot, and the anode (230), a plurality of metal sliding arc rails (240) and the cathode (220) are arranged in sequence at intervals and respectively installed on the ceramic substrate (210).

3. The externally attached multifunctional plasma flame stabilizer according to claim 2, characterized in that, The ceramic substrate (210) is provided with embedded grooves that are respectively adapted to the anode (230), a plurality of the metal sliding arc slide rails (240) and the cathode (220).

4. The externally attached multifunctional plasma flame stabilizer according to claim 2, characterized in that, The cathode (220) includes: a first extension (221) and a second extension (222); The first extension (221) extends along the x direction perpendicular to the air intake direction, and the second extension (222) is connected to one end of the first extension (221) near the metal sliding arc rail (240) and is inclined in a direction away from the metal sliding arc rail (240).

5. The externally attached multifunctional plasma flame stabilizer according to claim 4, characterized in that, The metal sliding arc slide rail (240) includes: a straight part (241), a first trapezoidal side part (242), and a second trapezoidal side part (243). The straight portion (241) is parallel to the first extension portion (221), and the straight portion (241) is connected between the first trapezoidal side portion (242) and the second trapezoidal side portion (243); The first trapezoidal side portion (242) and the second trapezoidal side portion (243) form an angle greater than 90 degrees with the straight portion (241).

6. The externally attached multifunctional plasma flame stabilizer according to claim 5, characterized in that, The first trapezoidal side portion (242) and the second trapezoidal side portion (243) are connected to the straight portion (241) at one end near the opening of the combustion region (101), and extend into the combustion region (101) respectively.

7. The externally attached multifunctional plasma flame stabilizer according to any one of claims 1 to 6, characterized in that, The two opposite skirt plates (110) are respectively provided with the slots, and the external actuators (200) are respectively installed in the two opposite slots.

8. The externally attached multifunctional plasma flame stabilizer according to any one of claims 1 to 6, characterized in that, The evaporative flame stabilizer (100) has a mixing chamber (102) and a partition (120) is installed between the mixing chamber (102) and the combustion zone (101). The partition (120) is provided with a plurality of dispersion holes, which are spaced apart.

9. The externally attached multifunctional plasma flame stabilizer according to claim 8, characterized in that, The evaporative flame stabilizer (100) is provided with an air inlet (130), and the mixing chamber (102) is located between the air inlet (130) and the partition (120).

10. The externally attached multifunctional plasma flame stabilizer according to claim 9, characterized in that, The evaporative flame stabilizer (100) is equipped with an oil injection device (140), which is inserted into the air inlet (130).

Images