Plasma synthesis of jet fuel nozzles

Abstract

The application provides a plasma synthetic jet fuel nozzle, a ring-shaped exciter sleeve is arranged on an oil supply pipeline, a plurality of air cavities are formed in the ring-shaped exciter, each air cavity is provided with a jet hole which is communicated to an outer end surface of the ring-shaped exciter, and the plurality of jet holes are arranged around the circumference of an oil injection port; each group of electrode pairs comprises a high-voltage electrode and a grounded electrode, each air cavity contains at least one group of electrode pairs, the discharge end of the high-voltage electrode and the discharge end of the grounded electrode are located in the air cavity, and a discharge interval is maintained between the discharge end of the high-voltage electrode and the discharge end of the grounded electrode; the electrode pairs are discharged by breaking the air through a high-voltage power supply, the electric arc generated by the discharge can instantaneously heat the gas in the air cavity, the pressure of the gas is suddenly increased, the gas is high-speed injected from the jet hole to form a shock wave and a high-speed jet, and the shock wave and the high-speed jet periodically act on the fuel injected from the oil supply pipeline to strengthen the breaking, atomization and mixing of the fuel. The nozzle does not need an external gas source, the electrodes are closed in the air cavity, and carbon deposition and ablation are avoided.

Description

Technical Field

[0001] This invention relates to a fuel injection technology for an aero-engine combustion chamber, specifically to a plasma synthetic jet fuel nozzle. Background Technology

[0002] Efficient combustion in an aero-engine combustor relies on the uniform mixing of fuel and air, and the atomization performance of the fuel nozzle is the core factor determining its mixing efficiency. Existing fuel nozzles (such as centrifugal, direct-injection, and pre-film types) can meet basic requirements under normal operating conditions (such as ground start-up and low-to-medium altitude cruise), but under extreme conditions at high altitudes and high speeds, they suffer from the following key drawbacks due to the dual limitations of environmental conditions and combustion characteristics: 1. Atomization quality drops sharply under high altitude and low pressure environment: The air pressure is low at high altitude, and the fuel viscosity increases as the temperature decreases. The jet / swirling shearing effect of the existing nozzle is weakened, which leads to an increase in fuel atomization particle size and a decrease in mixing uniformity. This can easily lead to local rich or lean fuel areas, causing unstable combustion, flameout, or even engine shutdown.

[0003] 2. Insufficient fuel penetration depth under high-speed airflow: For advanced aero engines such as scramjet, the incoming flow velocity in the combustion chamber can reach more than 1000m / s. The fuel jet kinetic energy of existing nozzles is limited, resulting in insufficient penetration depth. Fuel is unable to reach the central area of ​​the combustion chamber, leading to insufficient mixing time and increased emissions of unburned hydrocarbons.

[0004] 3. Poor adaptability to a wide range of operating conditions: Most existing nozzles adopt a fixed structure design, making it difficult to adapt to complex scenarios such as high altitude and low pressure, high-speed airflow, and variable operating conditions. For example, centrifugal nozzles have poor atomization quality at low flow rates, while direct-fire nozzles are prone to droplet agglomeration at high flow rates, failing to meet the high-efficiency combustion requirements of aero engines under all operating conditions.

[0005] 4. Insufficient low-temperature ignition performance: In high-altitude and low-temperature environments (such as below -50℃), the fuel atomization particle size is large and the evaporation rate is slow, making it difficult to effectively transfer ignition energy, resulting in a prolonged ignition delay time (up to 100ms or more), or even ignition failure, which seriously affects the starting reliability of the engine.

[0006] To address the aforementioned issues, plasma combustion control technology, with its unique thermal, chemical, and transport effects, has been widely applied in aero-engine combustion control research. However, existing technologies still have significant shortcomings. For example, Chinese invention patent CN120720126A, "An Ignition Device and Method for a Cavity Combustion Chamber Coupled with Flow Control and Ignition," uses arc discharge to improve ignition conditions in the cavity combustion chamber, but its electrodes are arranged on the surface of the combustion chamber, making them prone to failure due to carbon buildup. Chinese invention patent CN121383246A, "A Plasma Fuel Modification and Atomizing Injection Rod for Aero-engines," uses dielectric barrier discharge to improve fuel atomization and modification efficiency, but requires an external gas source, increasing system complexity.

[0007] In addition, other plasma combustion control technologies also have their own problems: sliding arc discharge ignition and combustion assisting devices require the introduction of an external gas source, which increases the complexity of the system; the electrodes of arc discharge ignition and combustion assisting devices are arranged on the surface of the combustion chamber, which may cause short circuit failure due to carbon buildup in the combustion chamber; the electrodes of dielectric barrier discharge ignition and combustion assisting devices are exposed in the turbulent combustion field, which is prone to unstable operation due to ablation; plasma torches and laser plasma ignition and combustion assisting devices have complex structures, making them difficult to apply in actual engineering.

[0008] Overall, existing plasma combustion control technologies suffer from problems such as increased system complexity due to the introduction of external gas sources and electrode failure due to ablation or carbon buildup. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the defects of the prior art, such as poor fuel atomization quality, insufficient penetration depth, poor adaptability to wide operating conditions and insufficient low-temperature ignition performance under extreme conditions of high altitude / high speed. The invention provides a plasma synthesis jet fuel nozzle that does not require an external air source, is not prone to electrode erosion or carbon buildup, and can simultaneously achieve fuel crushing, atomization and mixing control.

[0010] The present invention solves the above-mentioned technical problems through the following technical solutions: This invention provides a plasma-synthesized jet fuel nozzle, comprising a fuel supply line, an annular actuator, several electrode pairs, and a plasma power supply. A fuel injection channel is formed in the middle of the fuel supply line, and the port extending from the fuel injection channel to the outer end face of the fuel supply line is the fuel injection port. The annular actuator is fitted onto the fuel supply line, and several gas chambers are formed within the annular actuator. Each gas chamber has a jet hole communicating with the outer end face of the annular actuator, and the several jet holes are arranged circumferentially around the fuel injection port. Each electrode pair includes a high-voltage electrode and a ground electrode. Each gas chamber accommodates at least one electrode pair. The discharge ends of the high-voltage electrode and the ground electrode are located within the gas chambers, and a discharge distance is maintained between the discharge ends of the high-voltage electrode and the ground electrode. The connection ends of the high-voltage electrode and the ground electrode are located outside the annular actuator. The high-voltage output end of the plasma power supply is connected to the connection end of the high-voltage electrode, and the ground end of the plasma power supply is connected to the connection end of the ground electrode.

[0011] In this technical solution, the fuel supply pipeline supplies fuel to the combustion chamber. After being transported through the fuel injection channel, the fuel is ejected from the injection port to form a fuel jet. The annular exciter is coaxially sleeved on the fuel supply pipeline, ensuring that the jet orifices are evenly distributed around the injection port. This guarantees the symmetry and uniformity of the excitation-induced jet's effect on fuel injection from all directions, avoiding fuel agglomeration caused by unilateral action. The overall structure is compact with small circumferential dimensions, facilitating its arrangement within the limited space of the aero-engine combustion chamber. The high-voltage electrode and ground electrode of each electrode pair are used to receive the high-voltage pulse applied by the plasma power supply, generating an arc discharge within the gas cavity. The discharge end of the electrode is enclosed inside the gas cavity. Not directly exposed to the turbulent field of the combustion chamber, it fundamentally avoids the problem of electrodes short-circuiting due to carbon buildup or failing due to ablation, significantly extending its service life; at the same time, it does not require the introduction of an external gas source, making the system structure simple, lightweight, and easy to arrange in the combustion chamber; the plasma power supply is used to provide high-voltage pulsed electrical energy to the electrode pair. When the applied high-voltage pulse exceeds the breakdown threshold of the air in the electrode gap, the electrode gap is broken down and an electric arc is generated. The electric arc instantly heats the gas in the gas chamber, causing its pressure to rise sharply. The gas is ejected at high speed from the jet hole, forming a shock wave and a high-speed jet. This jet periodically acts on the fuel injected from the fuel supply line, realizing the breaking, atomization, and mixing of the fuel.

[0012] Preferably, the annular actuator includes an annular base and an annular cover plate. Both the annular base and the annular cover plate are fitted onto the oil supply pipeline. The opposite end faces of the annular base and the annular cover plate are attached to each other and fixed. The air chamber is located inside the annular base, and the jet hole is located on the annular cover plate.

[0013] In this technical solution, the separate structure of the annular base and the annular cover plate facilitates the processing and forming of the air chamber and the installation and maintenance of the electrode pairs, reducing manufacturing costs and assembly difficulty; the coaxial sleeve of the annular base and the annular cover plate ensures the circumferential positional accuracy of the jet hole and the fuel injection port, ensuring that the jet direction accurately points to the fuel injection area; as the carrier of the jet hole, the annular cover plate can be replaced with annular cover plates with different jet hole shapes, sizes and arrangements according to different working conditions, improving the serialization adaptability of the product.

[0014] Preferably, the air cavity is formed by an inward recess of the end face of the annular base facing the annular cover plate, the end face of the annular cover plate covering the annular base seals the air cavity, and the jet hole penetrates the end face of the annular cover plate and communicates with the air cavity.

[0015] In this technical solution, the recessed air cavity has a simple molding process. The mating end face of the annular cover plate and the annular base serves as a sealing surface, which can effectively prevent gas leakage, ensure the airtightness of the air cavity, and ensure that the pressure generated by the discharge can be fully converted into jet kinetic energy without loss. The way the annular cover plate seals the air cavity means that the volume accuracy of the air cavity is guaranteed by the machining accuracy of the annular base, which facilitates consistency control in mass production.

[0016] Preferably, the annular cover plate is provided with a through hole, and the end face of the annular base facing the annular cover plate is provided with a fixing hole. The through hole and the fixing hole are coaxially arranged. The fuel nozzle also includes a fixing connector, which is inserted into the through hole and the fixing hole and fixed to the through hole and the fixing hole.

[0017] In this technical solution, the connection method has a simple structure and reliable connection, which facilitates the quick assembly and disassembly of the annular cover plate and the annular base, and is beneficial for the maintenance and replacement of the electrode pair and the serial replacement of the annular cover plate.

[0018] Preferably, the axial height of the annular cover plate is 1~3mm, and the outer diameter of the annular cover plate is 20~40mm; the axial height of the annular base is 10~20mm, and the outer diameter of the annular base is 20~40mm.

[0019] In this technical solution, the above-mentioned size range is obtained by comprehensively optimizing the actual installation space of the aero-engine combustion chamber and the excitation effect of plasma-synthesized jet. The thickness of the annular cover plate is 1~3mm, which ensures the forming accuracy and structural strength of the jet hole, while avoiding excessive thickness that would increase jet resistance. The height of the annular base is 10~20mm, which ensures that the gas chamber has sufficient volume to generate a high-speed jet with sufficient flow, while controlling the compactness of the overall structure. The inner diameter of the annular structure matches the outer diameter of the fuel supply pipeline to ensure convenient installation.

[0020] Preferably, the air chamber includes a bottom surface of the chamber and a peripheral surface of the chamber surrounding the bottom surface of the chamber. The bottom surface of the chamber is located at the end of the air chamber away from the jet hole, and the electrode pair extends into the air chamber from the bottom surface of the chamber. The bottom surface of the chamber is located on the radial plane of the annular exciter, and the peripheral surface of the chamber is perpendicular to the bottom surface of the chamber.

[0021] In this technical solution, the regular geometric shape of the air cavity structure facilitates electric field analysis and optimization of discharge parameters, ensuring the positional accuracy and stability of the discharge end within the air cavity, and ensuring the repeatability of each discharge. The bottom surface of the cavity is located on a radial plane, so that the insertion direction of each electrode pair is perpendicular to the bottom surface of the cavity, ensuring the relative positional accuracy between the discharge end and the jet hole, which is beneficial to the precise control of the jet direction.

[0022] Preferably, the jet orifice is a circular orifice, and the axis of the jet orifice is perpendicular to the plane of the fuel injection port; or, the cross-section of the jet orifice is rectangular, and the axis of the jet orifice is perpendicular to the plane of the fuel injection port; the ratio of the long side to the wide side of the rectangle is 1 to 5; or, the jet orifice is an oblique orifice, and the jet orifice gradually approaches the fuel injection port from the direction of the air chamber to the outer end face of the annular actuator.

[0023] In this technical solution, the jet orifice serves as the channel for the high-pressure gas within the combustion chamber to be ejected outwards, and its geometry directly affects the direction, velocity, and spatial distribution of the jet. Circular orifices offer advantages such as simple manufacturing processes and low cost. Furthermore, the circular cross-section results in low flow resistance and a concentrated jet direction along the axial direction, enabling the generation of a columnar jet with a high peak velocity. This makes them suitable for applications requiring precise fuel jet impact and high jet directionality. Rectangular orifices can be further categorized into small aspect ratio rectangular orifices and large aspect ratio rectangular orifices (slits) based on their aspect ratio: small aspect ratio rectangular orifices produce a concentrated jet with a high peak velocity, exhibiting stronger penetration capabilities, making them suitable for applications requiring increased fuel penetration depth; large aspect ratio rectangular orifices (slits) generate a more uniform vortex distribution, promoting fuel-air mixing over a wider range, making them suitable for applications requiring a wider range of disturbances. By selecting the shape and aspect ratio of the jet orifice, the fuel nozzle can be adapted to different combustion chamber flow field characteristics and operational requirements. Compared to vertical holes, the jet generated by oblique holes is closer to the wall of the annular actuator, which can prolong the action path of the plasma-induced jet structure and active material in the near-wall region. It is suitable for working conditions that require the use of wall effects to extend the action time.

[0024] Preferably, the diameters of the high-voltage electrode and the grounding electrode are 1-2 mm, and the discharge spacing between the discharge ends of the high-voltage electrode and the grounding electrode in each electrode pair is 2-5 mm; when the jet orifice is a circular orifice, the diameter of the jet orifice is 1-4 mm; when the cross-section of the jet orifice is rectangular, the area of ​​the rectangular cross-section is... .

[0025] In this technical solution, the electrode diameter is 1-2 mm, ensuring sufficient conductive cross-sectional area to carry large pulse currents, while the tip effect helps reduce the breakdown voltage; the discharge gap is 2-5 mm, ensuring reliable breakdown and stable arc generation during nanosecond high-voltage pulse application, while avoiding excessively large discharge gaps leading to excessively high breakdown voltages or insufficient arc energy due to excessively small discharge gaps; the jet orifice diameter is 1-4 mm or the cross-sectional area is... This ensures that the jet orifice matches the volume of the air chamber and the discharge energy, thereby ensuring that a sufficient driving pressure difference can be established in the air chamber to generate a high-speed jet with a velocity that meets the requirements of fuel breakup. At the same time, it avoids insufficient injection speed due to an orifice that is too large or limited flow due to an orifice that is too small.

[0026] Preferably, the fuel injector also includes an inductor and at least one relay module. The inductor is connected in series between the high-voltage output terminal of the plasma power supply and the connection terminal of the high-voltage electrode of the nearest electrode pair. The connection terminal of the ground electrode of the electrode pair is connected to the connection terminal of the high-voltage electrode of the next electrode pair. The relay module includes a resistor and a capacitor connected in parallel. The relay module is configured in a one-to-one correspondence with the electrode pair. The relay module is connected in series between the connection terminal of the ground electrode and the ground terminal of the plasma power supply.

[0027] In this technical solution, the inductor is connected in series in the discharge circuit. During the nanosecond high-voltage pulse discharge, it can maintain the pulse current, stabilize the breakdown process, suppress the current overshoot in the early stage of discharge, extend the duration of the discharge current, ensure the full release of arc energy, protect the electrodes from ablation, and improve the repeatability and consistency of the discharge. In the relay module, the capacitor uses its DC blocking and AC passing characteristics to transmit the breakdown voltage, so that multiple air gaps are broken down sequentially, realizing multi-channel sequential discharge. This allows a single plasma power supply to drive multiple electrode pairs or multiple plasma synthesis jet fuel nozzles to work simultaneously, greatly improving the power supply utilization efficiency, reducing the system's demand for multiple high-voltage power supplies, and simplifying the circuit layout. The parallel resistor is used to discharge the residual charge on the capacitor after the discharge ends, preventing charge accumulation that could lead to false triggering, ensuring that each electrode gap returns to the same initial state before the next pulse arrives, and guaranteeing the synchronization and stability of multi-channel discharge.

[0028] Preferably, the plasma power supply is a nanosecond high-voltage pulse power supply with an output voltage amplitude of 0~20kV, a pulse width of 0~1ms, and a frequency of 1~20kHz; the inductor is 50 mH, the capacitor is 100 pF, and the resistor is 1 MΩ.

[0029] In this technical solution, the nanosecond high-voltage pulse power supply features a steep rise edge, narrow pulse width, and high repetition frequency, enabling it to inject instantaneous high-power electrical energy into the electrode pair. This rapidly heats the gas in the gas chamber and establishes high pressure, while the high-frequency discharge ensures the continuity of the jet and the periodicity of its effect on the fuel. The 50mH inductor, in conjunction with the steep leading edge of the nanosecond pulse, effectively suppresses the current spike at the initial stage of discharge, protecting the electrodes from ablation. The 100pF capacitor has appropriate impedance matching characteristics under the nanosecond pulse, ensuring reliable transmission of the breakdown voltage. The 1MΩ resistor completely discharges residual charge within the discharge gap, ensuring that each discharge gap returns to the same initial state before the next pulse arrives, guaranteeing the synchronization and stability of multi-channel discharge.

[0030] Preferably, the air chamber is cylindrical, and each air chamber contains a set of electrode pairs; and / or, the radial cross-section of the air chamber is a fan-shaped section, the air chamber extends circumferentially along the fuel injector, and each air chamber contains at least two sets of electrode pairs.

[0031] In this technical solution, the cylindrical gas chamber has a simple structure, is easy to manufacture, and has high heating efficiency, making it suitable for operating conditions requiring high jet velocities. The fan-shaped cross-section gas chamber has a larger volume, can store more high-pressure gas, and can generate a larger flow rate jet in a single discharge, making it suitable for operating conditions with larger fuel flow rates. The two configurations can be selected and switched according to operating conditions such as flight Mach number and flight altitude. When the flight Mach number Ma < 1.5 and the altitude < 8 km, the fan-shaped gas chamber configuration is used to improve fuel atomization performance through low-frequency, high-flow pulses when the fuel flow rate is large. When Ma ≥ 2.0 and the altitude > 12 km, the configuration is switched to the cylindrical gas chamber configuration, which utilizes high-frequency discharge to achieve transient penetration enhancement.

[0032] Preferably, the air chamber is cylindrical, and there are six air chambers. Each air chamber contains a set of electrode pairs. The six air chambers are divided into groups of three, and the two groups of air chambers are symmetrically distributed with the center of the fuel injector as the center of symmetry.

[0033] In this technical solution, the symmetrical arrangement of the six air chambers ensures that the jet holes uniformly surround the fuel injection port in the circumference. The pulse jets generated by each jet hole act on the central fuel jet from multiple directions simultaneously, achieving an all-round and uniform fuel breaking and atomization effect, and avoiding fuel agglomeration caused by unilateral action.

[0034] Preferably, the annular actuator includes an annular base and an annular cover plate, both of which are fitted onto the oil supply pipeline. The opposite end faces of the annular base and the annular cover plate are attached and fixed together. The air chamber is disposed within the annular base, and the jet hole is disposed on the annular cover plate. The outer diameter of the annular cover plate is 36 mm, and the axial height of the annular cover plate is 2 mm. The outer diameter of the annular base is 36 mm, and the axial height of the annular base is 15 mm. The diameter of the jet hole is 2 mm. The inner diameter of the air chamber is 6 mm, and the axial height of the air chamber is 12 mm. The high-voltage electrode and the ground electrode are tungsten needles, with a diameter of 1 mm. The discharge distance between the discharge ends of the high-voltage electrode and the ground electrode of each electrode pair is 4 mm. The diameter of the oil supply pipeline is 20 mm, and the diameter of the oil injection port is 2 mm.

[0035] In this technical solution, the specific dimensional parameters mentioned above are obtained by comprehensively optimizing the actual installation space of the aero-engine combustion chamber and the excitation effect of the plasma synthetic jet. Under this parameter combination, the total volume of the gas chamber is approximately 2035.8 mm². 3 The discharge spacing of 4mm ensures reliable breakdown in a large cavity volume, and the fuel atomization particle size, penetration depth and mixing uniformity can reach a better level.

[0036] Preferably, the cross-section of the air chamber is a fan shape, the number of air chambers is two, and three sets of electrode pairs are arranged in each air chamber; the two air chambers are symmetrically distributed with the center of the fuel injection port as the center of symmetry.

[0037] In this technical solution, the fan-shaped gas chamber extends circumferentially, and has a larger single-chamber volume than the cylindrical gas chamber, which can store more high-pressure gas and generate a larger flow rate jet in a single discharge. Three sets of electrode pairs are arranged in each fan-shaped gas chamber, and the three sets of electrode pairs are distributed circumferentially at intervals. In a single discharge cycle, three jets that break down sequentially can be generated, which increases the total jet volume and jet coverage of a single discharge. The two fan-shaped gas chambers are symmetrically distributed with the center of the fuel injection port as the center of symmetry, so that the two gas chambers are located on both sides of the fuel injection port, ensuring the circumferential uniformity of the jet's effect on fuel injection and avoiding fuel agglomeration caused by unilateral action.

[0038] Preferably, the annular actuator includes an annular base and an annular cover plate. Both the annular base and the annular cover plate are fitted onto the oil supply pipeline. The opposite end faces of the annular base and the annular cover plate are abutted and fixed together. The air chamber is located within the annular base, and the jet orifice is located on the annular cover plate. The outer diameter of the annular cover plate is 36 mm, and the axial height of the annular cover plate is 2 mm. The outer diameter of the annular base is 36 mm, and the axial height of the annular base is 15 mm. The diameter of the jet orifice is 2 mm. The cross-section of the air chamber consists of a sequentially connected outer arc-shaped edge, a first half... It consists of a round edge, an inner arc edge, and a second semicircular edge. The radius of the outer arc edge is 17mm, the radius of the inner arc edge is 11mm, the angle between the outer and inner arc edges is 90 degrees, the radius of the first and second semicircular edges is 3mm, and the axial height of the air chamber is 12mm. The high-voltage electrode and the grounding electrode are tungsten needles with a diameter of 1mm. The discharge distance between the discharge ends of the high-voltage electrode and the grounding electrode of each electrode pair is 4mm. The diameter of the oil supply pipeline is 20mm, and the diameter of the oil injection port is 2mm.

[0039] In this technical solution, under the specific combination of the above-mentioned dimensional parameters, the total volume of a single fan-shaped air cavity is approximately 3845.3 mm². 3 It is about 1.9 times the size of a cylindrical gas chamber. The larger chamber volume allows for the ejection of a larger flow rate of gas in a single discharge, resulting in a stronger ability to break up large volumes of fuel.

[0040] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0041] The positive and progressive effects of this invention are as follows: The aforementioned plasma-synthesized jet fuel nozzle requires no external gas source. The electrodes are enclosed within the gas chamber, preventing carbon buildup and erosion. Its simple structure, lack of moving parts, and ease of installation facilitate combustion control. In terms of combustion regulation, the periodic high-speed jet generates strong aerodynamic shearing and impact on the fuel injection, reducing fuel atomization particle size and increasing penetration depth. The jet-induced vortex structure promotes rapid mixing of fuel and air, and the high-energy particles carried by the jet lower the ignition energy threshold and shorten the ignition delay time. The thermal jet, through the thermal blockage effect and the vortex structure excited by KH instability, promotes extensive mixing of fuel and air, widening the reliable ignition boundary of the combustion chamber. The nanosecond high-voltage pulse power supply operates at frequencies in the kHz range, enabling precise energy injection from nanoseconds to milliseconds. Its fast response speed allows for real-time adjustment of discharge parameters based on flight Mach number, flight altitude, and other operating conditions, matching different flow field characteristics and achieving intelligent combustion control. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the structure of an embodiment of the plasma synthesis jet fuel nozzle of the present invention.

[0043] Figure 2 for Figure 1 The diagram shows a perspective view of the internal structure of a plasma synthesis jet fuel nozzle.

[0044] Figure 3 for Figure 1 The image shows a transverse cross-sectional view of the plasma synthesis jet fuel nozzle.

[0045] Figure 4 for Figure 1 The diagram shows the combination of the annular base and electrode pair of the plasma synthesis jet fuel nozzle.

[0046] Figure 5 for Figure 1 The diagram shows the structure of the annular cover plate of the plasma synthesis jet fuel nozzle.

[0047] Figure 6 for Figure 1 The circuit diagram shown is for a plasma synthesis jet fuel nozzle.

[0048] Figure 7 for Figure 1 The diagram shows the energy deposition stage of a plasma-synthetic jet fuel nozzle.

[0049] Figure 8 for Figure 1 The diagram shows the jet generation stage of a plasma-synthetic jet fuel nozzle.

[0050] Figure 9 for Figure 1 The diagram shows the intake recovery phase of a plasma synthesis jet fuel nozzle.

[0051] Figure 10 for Figure 1 The diagram shows the actual fuel injection status of the plasma synthesis jet fuel nozzle.

[0052] Figure 11 This is a schematic diagram of the structure of a second embodiment of the plasma synthesis jet fuel nozzle of the present invention.

[0053] Figure 12 for Figure 11 The diagram shows a perspective view of the internal structure of a plasma synthesis jet fuel nozzle.

[0054] Figure 13 for Figure 11 The image shows a transverse cross-sectional view of the plasma synthesis jet fuel nozzle.

[0055] Figure 14 for Figure 11The diagram shows the combination of the annular base and electrode pair of the plasma synthesis jet fuel nozzle.

[0056] Figure 15 for Figure 11 The diagram shows the structure of the annular cover plate of the plasma synthesis jet fuel nozzle.

[0057] Explanation of reference numerals in the attached figures Oil supply line 1 Fuel injection channel 11 Fuel injector 111 Ring exciter 2 air chamber 21 Cavity bottom surface 211 212 circumferential surface of cavity Outer arc edge 213 First semicircle 214 Inner arc edge 215 Second semicircle 216 Jet orifice 22 Annular base 23 Fixing hole 231 Annular cover plate 24 Mounting through hole 241 Electrode pair 3 High voltage electrode 31 Discharge terminal 311 of high voltage electrode High voltage electrode connection terminal 312 Grounding electrode 32 Discharge terminal 321 of the grounding electrode Grounding electrode connection terminal 322 Plasma power supply 4 High voltage output terminal 41 Grounding terminal 42 Inductor 5 Relay Module 6 Resistor 61 Capacitor 62 Detailed Implementation

[0058] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0059] Example 1 like Figures 1 to 6The image shows an embodiment of the plasma-synthesized jet fuel nozzle of the present invention. The plasma-synthesized jet fuel nozzle includes a fuel supply line 1, an annular actuator 2, several electrode pairs 3, and a plasma power supply 4. A fuel injection channel 11 is formed in the middle of the fuel supply line 1, and the port of the fuel injection channel 11 extending to the outer end face of the fuel supply line 1 is a fuel injection port 111. The annular actuator 2 is fitted onto the fuel supply line 1, and six gas chambers 21 are formed within the annular actuator 2. Each gas chamber 21 is provided with a jet hole 22 communicating with the outer end face of the annular actuator 2. Several jet holes 22 are arranged circumferentially around the fuel injection port 111. Each electrode pair 3 includes a high-voltage electrode 31 and a grounding electrode. 32. Each gas chamber 21 contains a set of electrode pairs 3. The discharge end 311 of the high-voltage electrode 31 and the discharge end 321 of the ground electrode 32 are located inside the gas chamber 21. A discharge distance is maintained between the discharge end 311 of the high-voltage electrode 31 and the discharge end 321 of the ground electrode 32. The connection end 312 of the high-voltage electrode 31 and the connection end 322 of the ground electrode 32 are located outside the annular exciter 2. The high-voltage output end 41 of the plasma power supply 4 is connected to the connection end 312 of the high-voltage electrode 31, and the ground end 42 of the plasma power supply 4 is connected to the connection end 322 of the ground electrode 32.

[0060] like Figures 7 to 9 As shown, the operation of this plasma-synthetic jet fuel nozzle in a single discharge cycle can be divided into three stages: 1) Energy deposition stage, such as Figure 7 As shown: When the plasma power supply 4 applies a high-voltage pulse to the high-voltage electrode 31, and the voltage between the electrodes exceeds the breakdown threshold of the air in the gas chamber 21, the air gap between the discharge end 311 of the high-voltage electrode 31 and the discharge end 321 of the ground electrode 32 is broken down, generating an electric arc discharge. The electric arc instantly releases a large amount of heat, rapidly heating the gas in the gas chamber 21, causing the temperature and pressure of the gas in the gas chamber 21 to rise sharply. At the same time, the shock wave and ion effect generated by the electric arc discharge propagate outward through the jet hole 22, directly acting on the fuel jet ejected from the fuel injection port 111 of the fuel supply line 1, applying initial aerodynamic disturbance before the fuel jet enters the main combustion zone of the combustion chamber, accelerating the initial breakup and atomization of the liquid fuel, laying the foundation for subsequent jet impact. During this stage, the high-voltage electrode 31 and the ground electrode 32 in the gas chamber 21 carry a pulsed large current, efficiently converting electrical energy into thermal energy deposited in the gaseous working medium in the gas chamber 21.

[0061] 2) Jet generation stage, such as Figure 8As shown, as the gas in the gas chamber 21 is continuously heated by the electric arc, the pressure inside the gas chamber 21 rapidly increases to a level far exceeding the external atmospheric pressure. Driven by the pressure difference, the high-temperature, high-pressure gas in the gas chamber 21 is ejected at high speed through the jet holes 22 on the annular cover plate 24, forming a plasma synthesis jet with extremely high velocity and momentum. This jet exerts a strong aerodynamic shearing effect on the fuel jet ejected from the fuel injector 111 of the fuel supply line 1. The impact of this high-speed jet on the fuel jet can significantly increase the fuel penetration depth, enabling the fuel to reach the central region of the combustion chamber. At the same time, the vortex structure induced on both sides of the jet can promote rapid mixing of fuel and air. In addition, the high-energy particles (such as electrons and ions) carried by the jet can reduce the fuel ignition energy threshold and shorten the ignition delay time. During this stage, the pressure inside the gas chamber 21 continuously pushes the gas out through the jet holes 22. The geometry of the jet holes 22 on the annular cover plate 24 determines the direction and velocity distribution of the jet, while the annular base 23 bears the pressure load inside the gas chamber 21, ensuring structural integrity. Furthermore, in the scramjet concave combustion chamber configuration, after the plasma synthetic jet is ejected from the jet hole 22, during the downstream convection process in the combustion chamber, the boundary layer thickens due to the thermal blockage effect, forces the streamlines to move outward and promotes the lifting of the shear layer, thereby stimulating the Kelvin-Helmholtz instability of the shear layer and promoting the generation of large-scale vortex structures. This can effectively promote the mixing of fuel and air over a larger range and widen the reliable ignition boundary of the combustion chamber.

[0062] 3) During the inspiratory recovery phase, such as Figure 9 As shown, with the continuous ejection of high-pressure gas from the gas chamber 21 and the end of the arc discharge, the pressure inside the gas chamber 21 gradually decreases to below the external atmospheric pressure. Driven by the pressure difference between the inside and outside, outside air is drawn into the gas chamber 21 through the jet hole 22. Since the jet hole 22 is close to the fuel injection port 111 of the fuel supply line 1, the weak air intake process can bring some fuel vapor and atomized droplets along with air into the gas chamber 21, forming a premixed gas of fuel vapor and air inside the gas chamber 21. During the next discharge cycle, this premixed gas is ejected again from the jet hole 22 with the jet, making the mixing distribution more uniform, which is beneficial to improving the uniformity and stability of combustion. During this stage, the gas pressure inside the gas chamber 21 changes from positive pressure to negative pressure. The jet hole 22 of the annular cover plate 24 also serves as the air intake. The fuel injection position of the fuel supply line 1 determines the content of fuel vapor in the intake working fluid.

[0063] The aforementioned periodic discharge and jet generation process is repeated under the drive of the plasma power supply 4 continuously outputting periodic high-voltage pulses, thereby achieving continuous enhancement and precise control of fuel injection.

[0064] Fuel supply line 1 supplies fuel to the combustion chamber. After being delivered through injection channel 11, the fuel is ejected from injection port 111, forming a fuel jet. An annular actuator 2 is coaxially mounted on fuel supply line 1, ensuring that the jet holes 22 are evenly distributed around injection port 111, guaranteeing the symmetry and uniformity of the fuel injection effect from all directions and preventing fuel agglomeration caused by unilateral action. The annular actuator 2's mounting method results in a compact overall structure and small circumferential dimensions, facilitating its placement within the limited space of the aero-engine combustion chamber. The high-voltage electrode 31 and ground electrode 32 of each electrode pair 3 receive high-voltage pulses applied by plasma power supply 4, generating an electric arc discharge within the gas chamber 21. The discharge ends 311 and 321 of the electrodes are enclosed within the gas chamber 21, not directly exposed to the turbulent flow field of the combustion chamber, fundamentally avoiding the problem of short circuits or failure due to carbon buildup or erosion, significantly extending service life. Simultaneously, no external gas source is required, making the system simple in structure, lightweight, and easy to arrange within the combustion chamber. The plasma power source 4 is used to provide high-voltage pulse power to the electrode pair 3. When the applied high-voltage pulse exceeds the breakdown threshold of the air in the electrode gap, the electrode gap is broken down and an electric arc is generated. The electric arc instantly heats the gas in the gas chamber 21, causing its pressure to rise sharply. The gas is ejected at high speed from the jet hole 22 to form a shock wave and a high-speed jet. This jet periodically acts on the fuel injected from the fuel supply line 1 to achieve fuel crushing, atomization and mixing.

[0065] The annular actuator 2 includes an annular base 23 and an annular cover plate 24. The annular base 23 and the annular cover plate 24 are both fitted onto the oil supply pipeline 1. The end faces of the annular base 23 and the annular cover plate 24 that are arranged opposite to each other are attached and fixed. The air chamber 21 is set inside the annular base 23, and the jet hole 22 is set on the annular cover plate 24.

[0066] The separate structure of the annular base 23 and the annular cover plate 24 facilitates the machining and forming of the air chamber 21 and the installation and maintenance of the electrode pair 3, reducing manufacturing costs and assembly difficulty. The coaxial fitting of the annular base 23 and the annular cover plate 24 ensures the circumferential positional accuracy of the jet hole 22 and the fuel injection port 111, ensuring that the jet direction accurately points to the fuel injection area. As the carrier of the jet hole 22, the annular cover plate 24 can be replaced with annular cover plates 24 with different jet hole shapes, sizes and arrangements according to different working conditions, improving the product's serialization adaptability.

[0067] like Figure 4 As shown, the air cavity 21 is formed by the inward recess of the end face of the annular base 23 facing the annular cover plate 24. The end face of the annular cover plate 24 covering the annular base 23 seals the air cavity 21. The jet hole 22 penetrates the end face of the annular cover plate 24 and communicates with the air cavity 21.

[0068] The recessed gas cavity 21 has a simple molding process. The mating end faces of the annular cover plate 24 and the annular base 23 serve as sealing surfaces, effectively preventing gas leakage and ensuring the airtightness of the gas cavity 21. This ensures that the pressure generated by the discharge can be fully converted into jet kinetic energy without loss. The way the annular cover plate 24 seals the gas cavity 21 allows the volume accuracy of the gas cavity 21 to be guaranteed by the machining accuracy of the annular base 23, facilitating consistency control in mass production.

[0069] like Figures 1 to 5 As shown, the annular cover plate 24 is provided with a fixing hole 241 that penetrates the annular cover plate 24, and the annular base 23 is provided with a fixing hole 231 on the end face facing the annular cover plate 24. The mounting through hole 241 and the fixing hole 231 are coaxially arranged. The fuel nozzle also includes a fixing connector (not shown in the figure). The fixing connector is inserted into the mounting through hole 241 and the fixing hole 231, and the fixing connector is fixed to the mounting through hole 241 and the fixing hole 231.

[0070] This connection method is simple in structure and reliable in connection, facilitating quick assembly and disassembly between the annular cover plate 24 and the annular base 23. It also benefits the maintenance and replacement of the electrode pair 3 and the serial replacement of the annular cover plate 24. The preferred fixing component is a bolt. The fixing hole 231 is a threaded hole, and the mounting through hole 241 is a smooth hole. The bolt shank passes through the mounting through hole 241 and engages with the internal thread of the fixing hole 231, thus locking the annular cover plate 24 to the annular base 23. The mounting through hole 241 provides space for the bolt head, allowing it to sink below the end face of the annular base 23, preventing the bolt from protruding from the end face of the annular base 23 and affecting the sealing effect of the air chamber 21.

[0071] The annular cover plate has an axial height of 1~3mm and an outer diameter of 20~40mm; the annular base has an axial height of 10~20mm and an outer diameter of 20~40mm.

[0072] The aforementioned dimensional range was optimized based on the actual installation space of the aero-engine combustion chamber and the excitation effect of the plasma-synthesized jet. The annular cover plate 24, with a thickness of 1-3 mm, ensures both the forming accuracy and structural strength of the jet orifice 22 while avoiding excessive thickness that would increase jet resistance. The annular base 23, with a height of 10-20 mm, ensures that the gas chamber 21 has sufficient volume to generate a high-speed jet with adequate flow, while also controlling the overall structural compactness. The outer diameter of the annular structure matches the outer diameter of the fuel supply line 1, ensuring ease of installation.

[0073] like Figures 2 to 4As shown, the air chamber 21 includes a bottom surface 211 and a peripheral surface 212 surrounding the bottom surface 211. The bottom surface 211 is located at the end of the air chamber 21 away from the jet hole 22. The electrode pair 3 extends from the bottom surface 211 into the air chamber 21. The bottom surface 211 is located on the radial plane of the annular exciter 2, and the peripheral surface 212 is perpendicular to the bottom surface 211.

[0074] The regular geometric shape of the gas cavity 21 facilitates electric field analysis and discharge parameter optimization, ensuring the positional accuracy and stability of the discharge terminals 311 and 321 within the gas cavity 21, and guaranteeing the repeatability and consistency of each discharge. The bottom surface 211 of the cavity is located on a radial plane, so that the insertion direction of each electrode pair 3 is perpendicular to the bottom surface 211 of the cavity, ensuring the relative positional accuracy between the discharge terminals 311 and 321 and the jet hole 22, which is beneficial for precise control of the jet direction.

[0075] Among them, the jet hole 22 is a circular hole, and the axis of the jet hole 22 is perpendicular to the plane where the fuel injection port 111 is located; or, the jet hole 22 is an oblique hole, and the jet hole 22 gradually approaches the fuel injection port 111 from the direction of the air chamber 21 to the outer end face of the annular actuator 2; or, the cross-section of the jet hole 22 is rectangular, and the axis of the jet hole 22 is perpendicular to the plane where the fuel injection port 111 is located; the ratio of the long side to the wide side of the rectangle is 1~5.

[0076] The jet orifice 22 serves as the channel for the high-pressure gas to be ejected outward from the gas chamber 21, and its geometry directly affects the direction, velocity, and spatial distribution of the jet. A circular orifice offers advantages such as simple manufacturing process and low cost. Furthermore, the circular cross-section results in low flow resistance and a concentrated jet direction along the axial direction, enabling the generation of a columnar jet with a high peak velocity. This is suitable for applications requiring a targeted fuel jet impact and high jet directionality. Compared to a circular orifice, an oblique orifice generates a jet that is closer to the wall of the annular actuator 2, extending the action path of the plasma active material in the near-wall region. This is suitable for applications requiring the use of wall effects to prolong the action time of the active material. Rectangular orifices can be further divided into small aspect ratio rectangular orifices and large aspect ratio rectangular orifices (slits) based on their aspect ratio: Small aspect ratio rectangular orifices (aspect ratio close to 1~3) produce concentrated jets with high peak velocities and stronger penetration capabilities, making them suitable for operating conditions requiring increased fuel penetration depth; large aspect ratio rectangular orifices (slits, aspect ratio close to 4~5) generate a more uniform vortex distribution, promoting fuel-air mixing over a wider range, making them suitable for operating conditions requiring a wide range of disturbances. By selecting the shape and aspect ratio of the jet orifice 22, the fuel nozzle can be adapted to different combustion chamber flow field characteristics and operating conditions.

[0077] The diameters of the high-voltage electrode and the grounding electrode are 1-2 mm, and the discharge spacing between the discharge ends of the high-voltage electrode and the grounding electrode in each electrode pair is 2-5 mm; when the jet orifice is circular, its diameter is 1-4 mm; when the cross-section of the jet orifice is rectangular, the area of ​​the rectangular cross-section is... .

[0078] The electrode diameter is 1-2 mm, ensuring sufficient conductive cross-sectional area to carry large pulse currents, while the tip effect helps reduce breakdown voltage. The discharge gap is 2-5 mm, ensuring reliable breakdown and stable arc generation during nanosecond high-voltage pulses, while avoiding excessively large discharge gaps leading to excessively high breakdown voltages or insufficient arc energy due to insufficient discharge gaps. The diameter of the jet orifice 22 is 1-4 mm, or the cross-sectional area is... This ensures that the volume and discharge energy of the jet orifice 22 are matched with those of the air chamber 21, thereby ensuring that a sufficient driving pressure difference can be established in the air chamber 21 to generate a high-speed jet with a speed that meets the requirements of fuel breakage. At the same time, it avoids insufficient injection speed due to an orifice that is too large or limited flow due to an orifice that is too small.

[0079] like Figure 6 As shown, the fuel nozzle also includes an inductor 5 and at least one relay module 6. The inductor 5 is connected in series between the high-voltage output terminal 41 of the plasma power supply 4 and the connection terminal 312 of the high-voltage electrode 31 of the nearest electrode pair 3. The connection terminal 322 of the ground electrode 32 of the electrode pair 3 is connected to the connection terminal 312 of the high-voltage electrode 31 of the next electrode pair 3. The relay module 6 includes a resistor 61 and a capacitor 62 connected in parallel. The relay module 6 is arranged in a one-to-one correspondence with the electrode pair 3. The relay module 6 is connected in series between the connection terminal 322 of the ground electrode 32 and the ground terminal 42 of the plasma power supply 4.

[0080] Inductor 5, connected in series in the discharge circuit, maintains the pulse current during nanosecond high-voltage pulse discharge, stabilizing the breakdown process, suppressing current overshoot in the initial stage of discharge, extending the duration of the discharge current, ensuring full release of arc energy, protecting the electrodes from ablation, and improving the repeatability and consistency of the discharge. In relay module 6, capacitor 62 utilizes its DC blocking and AC passing characteristics to transmit the breakdown voltage, causing multiple air gaps to break down sequentially, achieving multi-channel sequential discharge. This allows a single plasma power supply 4 to drive multiple electrode pairs 3 or multiple plasma synthesis jet fuel nozzles to operate simultaneously, significantly improving power supply efficiency, reducing the system's need for multiple high-voltage power supplies, and simplifying circuit layout. The parallel resistor 61 is used to discharge residual charge on capacitor 62 after discharge, preventing charge accumulation that could lead to false triggering, ensuring that each electrode gap returns to the same initial state before the next pulse arrives, and guaranteeing the synchronization and stability of multi-channel discharge.

[0081] Among them, plasma power supply 4 is a nanosecond high-voltage pulse power supply with an output voltage amplitude of 0~20kV, a pulse width of 0~1ms, and a frequency of 1~20kHz; inductor 5 is 50mH, capacitor 62 is 100pF, and resistor 61 is 1MΩ.

[0082] The nanosecond high-voltage pulse power supply features a steep rise time, narrow pulse width, and high repetition frequency, enabling it to inject instantaneous high-power electrical energy into electrode pair 3. This rapidly heats the gas in gas chamber 21 and establishes high pressure, while the high-frequency discharge ensures the continuity of the jet and the periodicity of its effect on the fuel. The 50mH inductor 5, in conjunction with the steep leading edge of the nanosecond pulse, effectively suppresses the current spike at the initial stage of discharge, protecting the electrodes from ablation. The 100pF capacitor 62 exhibits appropriate impedance matching characteristics under nanosecond pulse conditions, ensuring reliable transmission of breakdown voltage. The 1MΩ resistor 61 completely discharges residual charge within the discharge gap, ensuring that each discharge gap returns to the same initial state before the next pulse arrives, guaranteeing the synchronization and stability of multi-channel discharge.

[0083] In this embodiment, the air chambers 21 are cylindrical, and there are six air chambers 21. Each air chamber 21 contains a set of electrode pairs 3. The six air chambers 21 are arranged in groups of three, and the two groups of air chambers 21 are symmetrically distributed with the center of the fuel injection port 111 as the center of symmetry. The symmetrical arrangement of the six air chambers 21 ensures that the jet holes 22 uniformly surround the fuel injection port 111 in the circumference. The pulse jets generated by each jet hole 22 act on the central fuel jet from multiple directions simultaneously, achieving an all-round and uniform fuel breaking and atomization effect, and avoiding fuel agglomeration caused by unilateral action.

[0084] The annular cover plate 24 has an outer diameter of 36 mm and an axial height of 2 mm; the annular base 23 has an outer diameter of 36 mm and an axial height of 15 mm; the jet hole 22 has a diameter of 2 mm; the air chamber 21 has an inner diameter of 6 mm and an axial height of 12 mm; the high-voltage electrode 31 and the grounding electrode 32 are tungsten needles with a diameter of 1 mm, and the discharge distance between the discharge end 311 of the high-voltage electrode 31 and the discharge end 321 of the grounding electrode 32 in each electrode pair 3 is 4 mm; the oil supply line 1 has a diameter of 20 mm, and the oil injection port 111 has a diameter of 2 mm.

[0085] The specific dimensional parameters mentioned above were obtained through comprehensive optimization considering the actual installation space of the aero-engine combustion chamber and the excitation effect of the plasma synthetic jet. Under this parameter combination, the total volume of the gas chamber 21 is approximately 2035.8 mm². 3 With a discharge spacing of 4mm, reliable breakdown is ensured in a large cavity volume, and the fuel atomization particle size, penetration depth and mixing uniformity are all at a superior level.

[0086] like Figure 10 As shown, during fuel injection, the plasma-synthesized jet fuel nozzle exhibits good atomization after being ejected from the injection port 111. The jet cone angle is fully extended, the fuel jet is evenly distributed, and there is no obvious liquid core aggregation or deflection phenomenon. This indicates that the total volume of the plasma-synthesized jet fuel nozzle in the gas chamber 21 is approximately 2035.8 mm. 3 With a discharge spacing of 4 mm, the discharge breakdown is reliable, the plasma has a sufficient turbulence and agitation effect on the fuel, and the fuel atomization particle size, penetration depth and mixing uniformity are all at a good level, which verifies the effectiveness and rationality of the above-mentioned combination of structural parameters.

[0087] The aforementioned plasma-synthetic jet fuel nozzle exhibits several advantages in fuel atomization and combustion control. The periodic high-speed jet generates strong aerodynamic shearing and impact on the fuel injection, significantly reducing fuel atomization particle size and increasing fuel penetration depth. The jet-induced vortex structure promotes rapid mixing of fuel and air. The high-energy particles carried by the jet lower the ignition energy threshold and shorten the ignition delay time. Furthermore, the thermal blockage effect of the hot jet and the vortex structure excited by KH instability further promote fuel-air mixing on a larger scale, widening the reliable ignition boundary of the combustion chamber. In terms of operational adaptability, the nanosecond high-voltage pulse power supply operates at frequencies up to the kHz level, enabling precise energy injection from nanoseconds to milliseconds. Its fast response speed for excitation parameter control allows for real-time adjustment of discharge frequency and energy based on flight Mach number, flight altitude, and other operational conditions, matching different flow field characteristics and achieving intelligent combustion control.

[0088] Example 2 The other technical solutions in this embodiment are the same as in Embodiment 1. The difference lies in the shape of the air cavity and the number of electrode pairs it contains.

[0089] like Figures 11 to 15 As shown, the cross-section of the air chamber 21 is a fan shape, and there are two air chambers 21. Each air chamber 21 is equipped with three sets of electrode pairs 3. The two air chambers 21 are symmetrically distributed with the center of the fuel injection port 111 as the center of symmetry.

[0090] The fan-shaped gas chamber 21 extends circumferentially, possessing a larger single-chamber volume compared to a cylindrical gas chamber, enabling it to store more high-pressure gas and generate a larger flow rate jet in a single discharge. Each fan-shaped gas chamber 21 contains three sets of electrode pairs 3, spaced circumferentially. These three sets of electrode pairs 3 generate three sequentially breaking-down jets within a single discharge cycle, increasing the total jet volume and coverage area of ​​a single discharge. The two fan-shaped gas chambers 21 are symmetrically distributed around the center of the fuel injection port 111, ensuring the circumferential uniformity of the jet's effect on fuel injection and preventing fuel agglomeration caused by unilateral action. This fan-shaped gas chamber configuration is particularly suitable for flight conditions with Mach numbers Ma < 1.5 and altitudes < 8 km, where a single-chamber high-flow-rate pulse can effectively improve fuel atomization performance.

[0091] The annular cover plate 24 has an outer diameter of 36 mm and an axial height of 2 mm; the annular base 23 has an outer diameter of 36 mm and an axial height of 15 mm; the jet hole 22 has a diameter of 2 mm; the cross-section of the air cavity 21 consists of an outer arc-shaped edge 213, a first semicircular edge 214, an inner arc-shaped edge 215, and a second semicircular edge 216 connected in sequence. The radius of the outer arc-shaped edge 213 is 17 mm, the radius of the inner arc-shaped edge 215 is 11 mm, and the radius of the outer arc-shaped edge 216 is 17 mm. 13. The angle of the inner arc edge 215 is 90 degrees, the radius of the first semicircular edge 214 and the second semicircular edge 216 is 3mm, and the height of the air chamber 21 along the axial direction is 12mm; the high voltage electrode 31 and the grounding electrode 32 are tungsten needles, the diameter of the high voltage electrode 31 and the grounding electrode 32 is 1mm, and the discharge distance between the discharge end 311 of the high voltage electrode 31 and the discharge end 321 of the grounding electrode 32 of each electrode pair 3 is 4mm; the diameter of the oil supply line 1 is 20mm, and the diameter of the oil injection port 111 is 2mm.

[0092] Under the specific combination of the above-mentioned dimensional parameters, the total volume of a single fan-shaped air cavity 21 is approximately 3845.3 mm². 3 It is approximately 1.9 times the size of the cylindrical gas chamber in Example 1. The larger chamber volume allows for the ejection of a larger flow rate of gas in a single discharge, resulting in a stronger ability to break up large flow rates of fuel.

[0093] In other embodiments, the number, shape, or arrangement of the gas chambers 21 can also be different. For example, the number of cylindrical gas chambers 21 is not limited to six; it can be two, three, four, or more, evenly distributed circumferentially or non-uniformly distributed at a specific angle to achieve different jet spatial distributions and fuel action effects. The number of fan-shaped gas chambers 21 is also not limited to two; it can be three, four, or more, with each fan-shaped gas chamber 21 evenly arranged around the fuel injector 111 circumferentially to further increase the circumferential coverage density and uniformity of the jet. In addition, cylindrical gas chambers 21 and fan-shaped gas chambers 21 can also be mixed in the same annular exciter 2, so that some areas obtain concentrated high-speed jets and some areas obtain large-flow jets to meet the differentiated needs of fuel action modes in different directions. The number of electrode pairs 3 contained in each gas chamber 21 can also be adjusted according to the volume of the gas chamber 21 and the required jet intensity. For example, four or five sets of electrode pairs 3 can be arranged in a fan-shaped gas chamber 21 with a larger space to increase the total jet volume of a single discharge. Multiple jet holes 22 can also be arranged above the same air chamber 21, and each jet hole 22 can have a different aperture or orientation to generate multiple jets with different directions, thereby achieving a more complex flow field control effect. The above-mentioned variant schemes are all within the scope of the present invention. By adjusting the volume and number of air chambers 21, the arrangement of electrode pairs 3, and the arrangement of jet holes 22, the jet flow rate, velocity, and spatial distribution can be freely matched to adapt to different combustion chamber structures, flight conditions, and fuel supply conditions.

[0094] This invention is not limited to the embodiments described above. Any changes in shape or structure shall fall within the protection scope of this invention. The protection scope of this invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of this invention, but all such changes and modifications shall fall within the protection scope of this invention.

Claims

1. A plasma synthesis jet fuel nozzle, characterized in that, include: The fuel supply line has a fuel injection channel formed in the middle, and the port of the fuel injection channel extending to the outer end face of the fuel supply line is the fuel injection port. A ring actuator is fitted onto the oil supply line. Several air chambers are formed inside the ring actuator. Each air chamber is provided with a jet hole that communicates with the outer end face of the ring actuator. The several jet holes are arranged circumferentially around the oil injection port. Several electrode pairs, each electrode pair including a high-voltage electrode and a ground electrode, each air chamber accommodating at least one electrode pair, the discharge ends of the high-voltage electrode and the ground electrode being located inside the air chamber, a discharge distance being maintained between the discharge ends of the high-voltage electrode and the ground electrode, and the connection ends of the high-voltage electrode and the ground electrode being located outside the annular exciter. A plasma power supply, wherein the high-voltage output terminal of the plasma power supply is connected to the connection terminal of the high-voltage electrode, and the grounding terminal of the plasma power supply is connected to the connection terminal of the grounding electrode.

2. The plasma synthesis jet fuel nozzle as described in claim 1, characterized in that: The annular actuator includes an annular base and an annular cover plate. The annular base and the annular cover plate are both fitted onto the oil supply pipeline. The opposite end faces of the annular base and the annular cover plate are attached to each other and fixed. The air chamber is located inside the annular base, and the jet hole is located on the annular cover plate.

3. The plasma synthesis jet fuel nozzle as described in claim 2, characterized in that: The air cavity is formed by an inward recess of the end face of the annular base facing the annular cover plate. The annular cover plate covers the end face of the annular base to seal the air cavity. The jet hole penetrates the end face of the annular cover plate and communicates with the air cavity.

4. The plasma synthesis jet fuel nozzle as described in claim 2, characterized in that: The annular cover plate is provided with a through hole, and the end face of the annular base facing the annular cover plate is provided with a fixing hole. The through hole is coaxial with the through hole. The fuel nozzle also includes a fixing connector, which is inserted into the through hole and the fixing hole and fixed to the through hole and the fixing hole.

5. The plasma synthesis jet fuel nozzle as described in claim 2, characterized in that: The annular cover plate has an axial height of 1~3mm and an outer diameter of 20~40mm; the annular base has an axial height of 10~20mm and an outer diameter of 20~40mm.

6. The plasma synthesis jet fuel nozzle as described in claim 1, characterized in that: The air cavity includes a bottom surface of the cavity and a peripheral surface of the cavity surrounding the bottom surface of the cavity. The bottom surface of the cavity is located at the end of the air cavity away from the jet hole. The electrode pair extends from the bottom surface of the cavity into the air cavity. The bottom surface of the cavity is located on the radial plane of the annular actuator, and the peripheral surface of the cavity is perpendicular to the bottom surface of the cavity.

7. The plasma synthesis jet fuel nozzle as described in claim 1, characterized in that: The jet orifice is a circular orifice, and the axis of the jet orifice is perpendicular to the plane of the fuel injector. Alternatively, the cross-section of the jet orifice is rectangular, and the axis of the jet orifice is perpendicular to the plane of the fuel injector; the ratio of the long side to the wide side of the rectangle is 1 to 5. Alternatively, the jet orifice is an oblique orifice, and the jet orifice gradually approaches the oil injection port from the air chamber to the outer end face of the annular actuator.

8. The plasma synthesis jet fuel nozzle as described in claim 1, characterized in that: The diameter of the high-voltage electrode and the grounding electrode is 1-2 mm, and the discharge spacing between the discharge ends of the high-voltage electrode and the grounding electrode in each electrode pair is 2-5 mm; when the jet orifice is a circular orifice, the diameter of the jet orifice is 1-4 mm; when the cross-section of the jet orifice is rectangular, the area of ​​the rectangular cross-section is... .

9. The plasma synthesis jet fuel nozzle as described in claim 1, characterized in that, The fuel nozzle also includes: An inductor is connected in series between the high-voltage output terminal of the plasma power supply and the connection terminal of the high-voltage electrode of the nearest electrode pair, and the connection terminal of the ground electrode of the electrode pair is connected to the connection terminal of the high-voltage electrode of the next electrode pair. At least one relay module, the relay module including a resistor and a capacitor connected in parallel, the relay module being configured one-to-one with the electrode pair, and the relay module being connected in series between the connection terminal of the grounding electrode and the grounding terminal of the plasma power supply.

10. The plasma synthesis jet fuel nozzle as described in claim 9, characterized in that: The plasma power supply is a nanosecond high-voltage pulse power supply with an output voltage amplitude of 0~20kV, a pulse width of 0~1ms, and a frequency of 1~20kHz; the inductor is 50 mH, the capacitor is 100 pF, and the resistor is 1 MΩ.

11. The plasma synthesis jet fuel nozzle according to any one of claims 1 to 10, characterized in that: The air chamber is cylindrical, and each air chamber contains a set of electrode pairs; and / or, the radial cross-section of the air chamber is a fan, the air chamber extends circumferentially along the fuel injector, and each air chamber contains at least two sets of electrode pairs.

12. The plasma synthesis jet fuel nozzle according to any one of claims 1 to 10, characterized in that: The air chamber is cylindrical, and there are six air chambers. Each air chamber contains a set of electrode pairs. The six air chambers are arranged in groups of three, and the two groups of air chambers are symmetrically distributed with the center of the fuel injector as the center of symmetry.

13. The plasma synthesis jet fuel nozzle as described in claim 12, characterized in that: The annular actuator includes an annular base and an annular cover plate, both of which are fitted onto the oil supply pipeline. The opposite end faces of the annular base and the annular cover plate are attached and fixed together. The air chamber is disposed within the annular base, and the jet hole is disposed on the annular cover plate. The outer diameter of the annular cover plate is 36 mm, and the axial height of the annular cover plate is 2 mm. The outer diameter of the annular base is 36 mm, and the axial height of the annular base is 15 mm. The diameter of the jet hole is 2 mm. The inner diameter of the air chamber is 6 mm, and the axial height of the air chamber is 12 mm. The high-voltage electrode and the ground electrode are tungsten needles, each with a diameter of 1 mm. The discharge distance between the discharge ends of the high-voltage electrode and the ground electrode in each electrode pair is 4 mm. The diameter of the oil supply pipeline is 20 mm, and the diameter of the oil injection port is 2 mm.

14. The plasma synthesis jet fuel nozzle according to any one of claims 1 to 10, characterized in that: The cross-section of the air chamber is a fan shape, and there are two air chambers. Each air chamber is equipped with three sets of electrode pairs. The two air chambers are symmetrically distributed with the center of the fuel injector as the center of symmetry.

15. The plasma synthesis jet fuel nozzle as described in claim 14, characterized in that: The annular actuator includes an annular base and an annular cover plate, both of which are fitted onto the oil supply pipeline. The opposite end faces of the annular base and cover plate are abutted and fixed together. The air chamber is located within the annular base, and the jet orifice is located on the annular cover plate. The outer diameter of the annular cover plate is 36 mm, and its axial height is 2 mm. The outer diameter of the annular base is 36 mm, and its axial height is 15 mm. The diameter of the jet orifice is 2 mm. The cross-section of the air chamber consists of sequentially connected outer arc-shaped edges... The system consists of a first semicircular edge, an inner arc edge, and a second semicircular edge. The radius of the outer arc edge is 17mm, the radius of the inner arc edge is 11mm, the angle between the outer and inner arc edges is 90 degrees, the radius of the first and second semicircular edges is 3mm, and the axial height of the air chamber is 12mm. The high-voltage electrode and the grounding electrode are tungsten needles with a diameter of 1mm. The discharge distance between the discharge ends of the high-voltage electrode and the grounding electrode in each electrode pair is 4mm. The diameter of the oil supply pipeline is 20mm, and the diameter of the oil injection port is 2mm.

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