Engine electromagnetic acceleration fuel injection device and method

Abstract

The invention belongs to the field of engine fuel injection, and particularly relates to an engine electromagnetic accelerated fuel injection device and method. The device comprises a plasma generating device used for generating a plasma jet; the injection pipeline is used for conveying fuel; the mixing cavity is communicated with a jet flow outlet of the plasma generating device and an outlet of the injection pipeline, so that the plasma jet flow and the fuel are mixed in the mixing cavity, and a fuel and plasma mixed flow is formed; and the electromagnetic acceleration structure is arranged along the outlet direction of the mixing cavity and is used for carrying out electromagnetic acceleration on the plasma in the mixing cavity so as to drive the fuel and plasma mixed flow to be ejected in an accelerated manner. The device provides an effective technical solution for breaking through the bottleneck of the efficient combustion organization of the scramjet engine under the conditions of wide speed range and limited residence time.

Description

Technical Field

[0001] This invention belongs to the field of engine fuel injection, specifically relating to an engine electromagnetic acceleration fuel injection device and method. Background Technology

[0002] Engines, with their high specific impulse, simple structure, and high reliability at Mach numbers greater than 5, have become the preferred power system for cruise flight. In the combustion chamber, the inlet airflow Mach number is typically greater than 1, with airflow velocities reaching hundreds or even kilometers per second. However, the limited length of the combustion chamber results in extremely short fuel residence times, on the order of milliseconds. Within this brief residence time, liquid hydrocarbon fuels (especially aviation kerosene) must sequentially complete multiple physicochemical processes, including injection, atomization, evaporation, mixing, ignition, and stable combustion. Each of these processes directly affects the engine's combustion efficiency and thrust performance. Especially under wide-speed-range operating conditions, when the flight Mach number is below 4.0, the total temperature of the incoming airflow in the combustion chamber is low (<900K), making fuel self-ignition impossible, resulting in long ignition delays and difficulties in combustion organization. When the Mach number exceeds 7.0, the ultra-high-speed flow further reduces the fuel-air mixing efficiency and shortens the fuel residence time, drastically increasing the difficulty of combustion organization. Therefore, how to achieve efficient fuel atomization and rapid uniform mixing within a very limited time and space scale has become a key technical bottleneck restricting the performance improvement of scramjet engines, and is directly related to whether the engine can achieve reliable ignition, stable combustion and efficient thrust conversion. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide an electromagnetic acceleration fuel injection device and method for engines. By incorporating plasma into the fuel and using an electromagnetic field to accelerate it in a coordinated manner, an active and controllable fuel injection method is created, which effectively solves the key technical bottlenecks of insufficient fuel penetration depth and uneven mixing in scramjet engines, thereby significantly improving combustion efficiency and the engine's wide speed range performance.

[0004] This invention provides an electromagnetic acceleration fuel injection device for an engine, comprising: A plasma generator used to produce plasma jets; Injection lines are used to transport fuel; A mixing chamber is connected to the jet outlet of the plasma generator and the fuel outlet of the injection pipe, allowing the plasma jet and the fuel to mix within the mixing chamber to form a fuel-plasma mixture; and An electromagnetic acceleration structure is arranged along the outlet direction of the mixing cavity to electromagnetically accelerate the plasma within the mixing cavity, thereby accelerating the ejection of the fuel-plasma mixture.

[0005] Furthermore, the plasma generating device includes an axially extending inner tube that forms a flow channel for the plasma jet. It also includes an outer tube sleeved outside the inner tube, and an annular cavity is formed between the inner wall of the outer tube and the outer wall of the inner tube. This annular cavity constitutes the injection pipeline. The axial length of the outer tube is greater than the axial length of the inner tube, such that one end of the outer tube extends beyond the outlet of the inner tube, and the inner cavity of this extended portion constitutes the mixing cavity.

[0006] Furthermore, the plasma generating device also includes: The positive center electrode is arranged axially in the internal flow channel of the inner tube; The inner tube wall serves as the negative electrode for discharge; A high-voltage radio frequency generator, electrically connected to the positive center electrode and the wall of the inner tube, is used to apply a radio frequency voltage between the positive center electrode and the wall of the inner tube to generate the plasma jet.

[0007] Furthermore, the inlet end of the inner tube is configured as an air inlet for receiving external gas. When the gas flows through the inner tube, it is ionized under the action of the plasma generator to form the plasma jet.

[0008] Furthermore, the outlet end of the inner tube is formed as a contracting structure that shrinks in the axial direction.

[0009] Furthermore, the outlet section of the injection pipeline is formed as an annular channel that gradually expands along the injection direction.

[0010] Furthermore, the electromagnetic acceleration structure includes at least two sets of annular electromagnets arranged alternately along the axial direction of the mixing cavity; Each group of annular electromagnets is independently controlled to generate an axially alternating magnetic field within the mixing cavity to electromagnetically accelerate the plasma.

[0011] Furthermore, the annular electromagnet is wound around the outside of the outer tube.

[0012] Furthermore, a jet plug is provided at the outlet of the mixing chamber, and a jet nozzle is provided on the jet plug for accelerating the ejection of the fuel-plasma mixture.

[0013] The present invention also provides an engine electromagnetic acceleration fuel injection method, using the above-mentioned engine electromagnetic acceleration fuel injection device, comprising the following steps: Generates a plasma jet; Fuel is injected and mixed with the plasma jet within the mixing chamber to form a fuel-plasma mixture. An electromagnetic acceleration force is applied to the plasma within the mixing chamber to accelerate the ejection of the fuel-plasma mixture.

[0014] This invention, by mixing fuel with plasma and using electromagnetic force to synergistically accelerate it, has the following beneficial effects: 1. Significantly improves injection penetration depth. Electromagnetic acceleration gives the fuel-plasma mixture a much greater initial momentum than traditional pressure injection, enabling it to penetrate into the core flow region of the combustion chamber, thus solving the problem of insufficient penetration of wall injection.

[0015] 2. Active enhancement of the mixing process is achieved. The high-speed injected fuel and plasma mixture flow and the supersonic incoming flow generate severe shear, which greatly enhances the intensity and rate of turbulent mixing and shortens the mixing distance.

[0016] 3. It has the potential for wide-range adaptive operation. By adjusting plasma energy, electromagnetic field strength and timing, it can flexibly control injection speed and energy, thereby adapting to the different combustion organization requirements of the engine at different flight Mach numbers (such as low Mach number ignition assistance and high Mach number deep mixing).

[0017] 4. The structure is simple and efficient. Compared with the intrusive support plate, the device does not need to penetrate the large-scale mechanical structure of the mainstream, avoiding huge total pressure loss and complex thermal protection problems, and the propulsion efficiency is higher.

[0018] In summary, this device provides an effective technical solution to overcome the bottleneck of efficient combustion organization in scramjet engines under wide speed range and limited residence time conditions. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the cross-sectional structure of the present invention; Figure 2 This is a schematic diagram of the overall structure of the present invention; Figure 3 This is a schematic diagram of the front section structure of the present invention.

[0020] In the figure, 1-plasma generator; 11-jet outlet; 12-high voltage radio frequency generator; 2-injection pipeline; 21-fuel outlet; 3-mixing chamber; 4-inner tube; 5-outer tube; 6-positive center electrode; 7-ring electromagnet; 8-injection plug; 9-plasma jet; 10-fuel. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] 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 positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0023] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0026] like Figures 1-3 As shown, the present invention provides an electromagnetic acceleration fuel injection device for an engine, comprising: Plasma generator 1 is used to generate plasma jet 9; specifically, it ionizes a working gas (such as air) to generate a high-temperature, high-energy plasma jet 9. This enables the stable generation of plasma with controllable ionization, providing an effective charged working medium for subsequent electromagnetic acceleration.

[0027] Injection line 2 is used to deliver fuel; specifically, it is used to deliver fuel 10 (such as liquid hydrocarbon fuel, especially aviation kerosene). It ensures that the fuel is delivered to the mixing zone at the required flow rate and in the required condition.

[0028] The mixing chamber 3 is connected to the jet outlet 11 of the plasma generator 1 and the fuel outlet 21 of the injection pipe 2, so that the plasma jet 9 and the fuel 10 are mixed in the mixing chamber 3 to form a fuel-plasma mixture. In this chamber, the high-speed plasma jet 9 and the fuel 10 are initially mixed to form a uniform fuel-plasma mixture. This mixing chamber provides sufficient shearing and mixing space for the gas-liquid two phases.

[0029] as well as An electromagnetic acceleration structure, arranged along the outlet direction of the mixing cavity 3, is used to electromagnetically accelerate the plasma within the mixing cavity 3, thereby accelerating the ejection of the fuel-plasma mixture. Specifically, the electromagnetic acceleration structure applies an electromagnetic acceleration force (Lorentz force) to the plasma components in the mixture within the mixing cavity 3 by generating an electromagnetic field of a specific shape (such as an alternating pulsed magnetic field). The accelerated plasma, through momentum exchange, drives the entire fuel-plasma mixture to achieve an extremely high exit velocity.

[0030] This invention, by mixing fuel with plasma and using electromagnetic force to synergistically accelerate it, has the following beneficial effects: 1. Significantly improves injection penetration depth. Electromagnetic acceleration gives the fuel-plasma mixture a much greater initial momentum than traditional pressure injection, enabling it to penetrate into the core flow region of the combustion chamber, thus solving the problem of insufficient penetration of wall injection.

[0031] 2. Active enhancement of the mixing process is achieved. The high-speed injected fuel and plasma mixture flow and the supersonic incoming flow generate severe shear, which greatly enhances the intensity and rate of turbulent mixing and shortens the mixing distance.

[0032] 3. It has the potential for wide-range adaptive operation. By adjusting plasma energy, electromagnetic field strength and timing, it can flexibly control injection speed and energy, thereby adapting to the different combustion organization requirements of the engine at different flight Mach numbers (such as low Mach number ignition assistance and high Mach number deep mixing).

[0033] 4. The structure is simple and efficient. Compared with the intrusive support plate, the device does not need to penetrate the large-scale mechanical structure of the mainstream, avoiding huge total pressure loss and complex thermal protection problems, and the propulsion efficiency is higher.

[0034] In summary, this device provides an effective technical solution to overcome the bottleneck of efficient combustion organization in scramjet engines under wide speed range and limited residence time conditions.

[0035] Compared to existing technologies (such as CN120062002A) that construct the main propulsion system of an engine by ionizing and magnetically accelerating air, this application creatively applies the principle of electromagnetic acceleration to solve the specific bottleneck problem of insufficient fuel mixing in the combustion chamber of a scramjet engine. It proposes a scheme that uses plasma as a momentum carrier to pre-incorporate into the fuel to form a mixed flow, and then uses electromagnetic force to directly accelerate this mixed flow to achieve active, high-speed, and deep fuel injection.

[0036] In one embodiment, the plasma generating device 1 includes an axially extending inner tube 4, which forms a flow channel for the plasma jet 9. It also includes an outer tube 5 sleeved outside the inner tube 4, and an annular cavity is formed between the inner wall of the outer tube 5 and the outer wall of the inner tube 4. This annular cavity constitutes the injection pipeline 2. The axial length of the outer tube 5 is greater than the axial length of the inner tube 4, such that one end of the outer tube 5 extends beyond the outlet of the inner tube 4, and the inner cavity of this extended portion constitutes the mixing cavity 3.

[0037] In this embodiment, the following effects are achieved: 1. Through the coaxial sleeve design of the inner tube 4 and the outer tube 5, the plasma generation channel, fuel delivery channel, and mixing chamber 3 are highly integrated radially and have a continuous axial layout. This greatly saves installation space and reduces weight, making it very suitable for installation on the walls or inside the support plates of engine combustion chambers where space is limited.

[0038] 2. The annular injection pipe 2 uniformly surrounds the high-speed plasma jet 9 at the center from all sides. When the two meet in the mixing chamber 3, the fuel 10 naturally wraps around and penetrates into the plasma jet 9 from the circumferential direction, forming an initial, relatively uniform fuel-plasma mixture under shearing action. This premixing provides a good working fluid basis for subsequent electromagnetic acceleration, avoiding excessively high or low local concentrations.

[0039] 3. When fuel 10 flows in the annular injection pipe 2, it is in close proximity to the high-temperature inner pipe 4 wall, which effectively preheats it. This helps to reduce the viscosity of fuel 10, promote its atomization and evaporation, and even partially vaporize it before entering the mixing chamber 3, thereby shortening the evaporation time in the combustion chamber and increasing the combustion reaction rate.

[0040] 4. The coaxial structure ensures symmetrical and stable flow at the inlet of mixing chamber 3. A stable shear layer is formed between the plasma jet 9 and the annular fuel jet, which is conducive to the development of turbulence and the generation of large-scale vortex structures. This is also an effective passive mixing mechanism, which, together with the subsequent active electromagnetic acceleration, forms a passive-active composite enhanced mixing mode.

[0041] In summary, this embodiment, through its ingenious coaxial tube structure, not only achieves functional integration but also produces synergistic enhancement effects in premixing, preheating, thermal protection, and fluid organization, laying a solid physical foundation for ultimately achieving high-speed, deep fuel injection.

[0042] In one embodiment, the plasma generating device 1 further includes: The positive center electrode 6 is arranged axially in the internal flow channel of the inner tube 4; The inner tube 4 serves as the negative electrode for discharge; A high-voltage radio frequency generator 12 is electrically connected to the positive center electrode 6 and the tube wall of the inner tube 4, and is used to apply a radio frequency voltage between the positive center electrode 6 and the tube wall of the inner tube 4 to generate the plasma jet 9.

[0043] In this embodiment, the wall of the inner tube 4 is directly used as the negative electrode for discharge, eliminating the need for a separate negative electrode structure. This significantly simplifies the electrode system, reduces the number of components and assembly interfaces, and improves the integration and reliability of the structure. The positive electrode center electrode 6 is arranged along the axial direction of the inner tube 4, forming a symmetrical discharge space with the inner tube wall, which serves as the negative electrode. This facilitates the formation of a uniform and stable electric field distribution within the flow channel, thereby generating a uniformly expanding and stable plasma jet 9 along the axial direction. Furthermore, the inner tube wall, serving as the negative electrode for discharge and directly contacting the plasma, also acts as a carrier of the heat load. This structure facilitates the conduction of heat generated by the discharge through the tube wall, preheating the fuel.

[0044] In one embodiment, the inlet end of the inner tube 4 is configured as an air inlet for receiving external gas. As the gas flows through the inner tube 4, it is ionized by the plasma generator 1 to form the plasma jet 9. In this embodiment, the gas can be a single gas or a combination of gases that are easily ionized, such as air. In this case, ionizing air into plasma and premixing it with fuel achieves premixing of fuel and oxidant.

[0045] In one embodiment, the outlet end of the inner tube 4 is formed as a contracting structure that tapers in the axial direction. In this embodiment, the contracting structure accelerates the plasma jet 9, significantly increasing its outlet velocity and kinetic energy. This provides a higher initial momentum basis for subsequent mixing with fuel 10 in the mixing chamber 3 and for receiving electromagnetic acceleration, which is an important prerequisite for achieving high-speed injection.

[0046] In one embodiment, the outlet section of the injection conduit 2 is formed as an annular channel that gradually expands along the injection direction. In this embodiment, the expanding channel guides the fuel jet 10 to acquire an outward radial velocity component as it leaves the outlet. This allows it to meet the high-speed, concentrated plasma jet 9 ejected from the centrally contracting inner tube 4 at a better incident angle. The fuel jet 10 more effectively "wraps" around and penetrates into the plasma core from the side, increasing the contact area and shear surface between the two, thereby achieving more thorough and uniform initial mixing in the inlet region of the mixing chamber 3.

[0047] In a preferred embodiment, the contraction structure and the diffusion mechanism are implemented through a tapered tube structure at the end of the inner tube 4. In this embodiment, the tapered tube structure at the end of the inner tube 4 simultaneously achieves the accelerated contraction of the plasma jet 9 and the guided diffusion of the fuel loop.

[0048] In one embodiment, the electromagnetic acceleration structure includes at least two sets of annular electromagnets 7 arranged alternately along the axial direction of the mixing cavity 3; Each of the ring electromagnets 7 is independently controlled and is used to generate an axially alternating magnetic field within the mixing cavity 3 to electromagnetically accelerate the plasma.

[0049] In this embodiment, at least two sets of annular electromagnets 7 arranged alternately along the axial direction can generate an axially moving magnetic field wave within the mixing cavity 3 by independently and controllably switching on and off or changing the direction of the current. This traveling magnetic field continuously interacts with the plasma components in the fuel-plasma mixture, applying an axial electromagnetic force (Lorentz force), thereby achieving continuous, smooth, and efficient directional acceleration of the plasma and its driven mixture, avoiding the flow field pulsation or low energy conversion efficiency problems that may be caused by single-point pulse acceleration.

[0050] In one embodiment, the annular electromagnet 7 is wound around the outside of the outer tube 5.

[0051] In this embodiment, the design of winding the annular electromagnet 7 around the outer tube 5 achieves a high degree of synergy between structure, thermal management and function: First, this layout allows the annular electromagnet 7 to tightly surround the outer wall of the mixing cavity 3, so that the alternating magnetic field it generates can penetrate the wall of the outer tube 5 most directly and efficiently and act on the plasma in the cavity, maximizing energy coupling efficiency, while ensuring that there are no components inside the flow channel that affect the flow, maintaining excellent aerodynamic characteristics.

[0052] In one embodiment, a nozzle 8 is provided at the outlet of the mixing chamber 3, and the nozzle 8 has a nozzle opening for accelerating the ejection of the fuel-plasma mixture. In this embodiment, the nozzle opening of a specific geometric shape and size on the nozzle 8 provides final constraint, guidance, and shaping of the electromagnetically accelerated fuel-plasma mixture. This structure can efficiently convert the kinetic energy of the fuel-plasma mixture into a high-speed jet with highly concentrated direction and controllable morphology (such as jet diameter and diffusion angle), thereby precisely controlling its penetration depth and spatial distribution, and directly optimizing its mixing and combustion process in the combustion chamber.

[0053] The present invention also provides an engine electromagnetic acceleration fuel injection method, using the above-mentioned engine electromagnetic acceleration fuel injection device, comprising the following steps: Generates a plasma jet 9; Fuel 10 is injected and mixed with plasma jet 9 in mixing chamber 3 to form fuel-plasma mixed flow; An electromagnetic acceleration force is applied to the plasma within the mixing chamber 3 to accelerate the ejection of the fuel-plasma mixture.

[0054] The above description is merely an embodiment and does not constitute any limitation on the present invention. Any person skilled in the art can make many possible variations, modifications, or alterations to the technical solutions of the present invention without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should fall within the protection scope of the present invention.

Claims

1. An electromagnetic acceleration fuel injection device for an engine, characterized in that, include: Plasma generator (1) is used to generate plasma jet (9). Injection line (2), used to transport fuel; The mixing chamber (3) is connected to the jet outlet (11) of the plasma generator (1) and the fuel outlet (21) of the injection pipe (2), so that the plasma jet (9) and the fuel (10) are mixed in the mixing chamber (3) to form a fuel-plasma mixture; and An electromagnetic acceleration structure is arranged along the outlet direction of the mixing cavity (3) to electromagnetically accelerate the plasma in the mixing cavity (3), thereby driving the fuel and plasma mixture to be ejected at an accelerated speed.

2. The engine electromagnetic acceleration fuel injection device as described in claim 1, characterized in that, The plasma generating device (1) includes an inner tube (4) extending along the axial direction, the inner tube (4) forming the flow channel of the plasma jet (9). It also includes an outer tube (5) sleeved outside the inner tube (4), and an annular cavity is formed between the inner wall of the outer tube (5) and the outer wall of the inner tube (4), which constitutes the injection pipeline (2). The axial length of the outer tube (5) is greater than the axial length of the inner tube (4), such that one end of the outer tube (5) extends beyond the outlet of the inner tube (4), and the inner cavity of the extended portion constitutes the mixing cavity (3).

3. The engine electromagnetic acceleration fuel injection device as described in claim 1, characterized in that, The plasma generating device (1) further includes: The positive center electrode (6) is arranged axially in the internal flow channel of the inner tube (4); The inner tube (4) wall serves as the negative electrode for discharge; A high-voltage radio frequency generator (12) is electrically connected to the positive center electrode (6) and the tube wall of the inner tube (4) to apply a radio frequency voltage between the positive center electrode (6) and the tube wall of the inner tube (4) to generate the plasma jet (9).

4. The engine electromagnetic acceleration fuel injection device as described in claim 3, characterized in that, The inlet end of the inner tube (4) is configured as an air inlet for receiving external gas. When the gas flows through the inner tube (4), it is ionized under the action of the plasma generator (1) to form the plasma jet (9).

5. The engine electromagnetic acceleration fuel injection device as described in any one of claims 2-4, characterized in that, The outlet end of the inner tube (4) is formed as a contraction structure that contracts in the axial direction.

6. The engine electromagnetic acceleration fuel injection device as described in any one of claims 2-4, characterized in that, The outlet section of the injection pipeline (2) is formed as an annular channel that gradually expands along the injection direction.

7. The engine electromagnetic acceleration fuel injection device as described in any one of claims 2-4, characterized in that, The electromagnetic acceleration structure includes at least two sets of annular electromagnets (7) arranged alternately along the axial direction of the mixing cavity (3). Each of the ring electromagnets (7) is independently controlled to generate an axially alternating magnetic field within the mixing cavity (3) to electromagnetically accelerate the plasma.

8. The engine electromagnetic acceleration fuel injection device as described in claim 7, characterized in that, The annular electromagnet (7) is wound around the outside of the outer tube (5).

9. The engine electromagnetic acceleration fuel injection device as described in any one of claims 1-4, characterized in that, in The outlet of the mixing chamber (3) is provided with a jet plug (8), and the jet plug (8) has a jet port for accelerating the ejection of the fuel and plasma mixture.

10. A method for electromagnetic acceleration fuel injection in an engine, characterized in that, Using the engine electromagnetic acceleration fuel injection device as described in any one of claims 1-9, the method includes the following steps: Generate a plasma jet (9); Fuel (10) is injected and mixed with the plasma jet (9) in the mixing chamber (3) to form a fuel-plasma mixed flow; An electromagnetic acceleration force is applied to the plasma in the mixing chamber (3) to drive the fuel and plasma mixture to be ejected at an accelerated speed.

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