Marine and air amphibious fuel injection system and method based on methanol activated aluminum-water system fuel

Abstract

The application discloses a sea-air amphibious fuel injection system and method based on a methanol-activated aluminum-water system fuel, the fuel injection system comprising a needle injection device, the needle injection device having coaxially arranged inner and outer flow channels and a flow regulating unit; the inner wall of the inner flow channel and the inner wall of the outer flow channel have a plurality of inner flow channel bosses and a plurality of outer flow channel bosses arranged alternately along the axial direction, which are used for generating local vortex when the fuel flows; the method comprises: a magnetic stirring device stirring the fuel in a high-concentration Al / MeOH fuel storage tank; a mixing device proportionally mixing the fuel output by the high-concentration Al / MeOH fuel storage tank and a methanol MeOH fuel storage tank; a fuel injection system receiving and injecting the mixed methanol-activated aluminum fuel and introducing seawater or air as an oxidant; the application can enhance mixing through vortex, adapt to seawater / air dual oxidants, adjust the fuel ratio to improve the combustion efficiency, and realize sea-air amphibious high-efficiency power.

Description

Technical Field

[0001] This invention belongs to the field of amphibious propulsion system technology, and particularly relates to an amphibious fuel injection system and injection method based on methanol-activated aluminum-water fuel system. Background Technology

[0002] Future high-speed, long-range underwater mobile weapons and low-altitude / underwater amphibious platforms place extremely high demands on their propulsion systems, requiring them to possess high energy density, wide operating condition adaptability, and multi-environment (underwater / air) capability. The methanol-activated aluminum-water reaction system, due to its extremely high volumetric energy density, is considered a highly promising propulsion fuel. However, applying this type of slurry fuel to practical variable-thrust propulsion systems, especially in amphibious environments, faces a series of key technological challenges, and existing technological solutions have significant shortcomings: 1. Fuel Stability and Supply Challenges: High concentrations and high reactivity of micron-sized aluminum particles in the fuel readily settle, agglomerate, and even adhere to the inner walls of the flow channels in methanol. Traditional mechanical stirring methods have limited effectiveness under long-term operation or varying operating conditions, making it difficult to ensure the long-term uniformity and stability of the fuel composition. This not only leads to uneven fuel energy release and reduced combustion efficiency but may also cause blockages in the dispensing pipeline and injectors, seriously affecting system reliability and safety.

[0003] 2. The contradiction between wide-range thrust adjustment and atomization quality: Amphibious propulsion systems need to switch between various operating conditions, such as underwater cruise, high-speed penetration, and aerial flight, requiring engines to have a wide range of thrust adjustment capabilities (e.g., no less than 5:1). Although needle-type injectors have a certain potential for variable thrust, they face a fundamental contradiction when achieving deep thrust adjustment, especially under low-flow conditions: simply reducing the injection area to reduce the flow rate will severely weaken the collision momentum between the radial jet and the axial liquid film, resulting in a sharp contraction of the spray cone angle, a significant increase in atomized particle size, and poor combustion stability, making it impossible to maintain optimal atomization and mixing conditions throughout the entire thrust adjustment range.

[0004] 3. Multi-working-medium oxidizer adaptability: The system needs to alternate between seawater (underwater) and air (air) as oxidizers, and the physical properties (density, oxidizing components, compressibility) of the two are vastly different. Traditional injection systems are usually optimized for a single oxidizer, making it difficult to achieve efficient fuel atomization, mixing, and combustion organization in two drastically different oxidizer environments, thus limiting the cross-medium working capability of the power system.

[0005] Therefore, there is an urgent need for an innovative fuel injection system that can fundamentally solve the problem of stable supply of aluminum-based slurry fuel, achieve stable and efficient atomization over a wide thrust range, and flexibly adapt to both seawater and air oxidizer environments, thereby releasing the application potential of methanol-activated aluminum-water system fuel in amphibious propulsion systems. Summary of the Invention

[0006] This invention addresses the problems existing in the prior art by proposing a marine and air amphibious fuel injection system and method based on methanol-activated aluminum-water fuel. The aim is to fundamentally solve the problem of stable supply of aluminum-based slurry fuel, achieve stable and efficient atomization over a wide thrust range, and flexibly adapt to both seawater and air oxidizer environments, thereby releasing the application potential of methanol-activated aluminum-water fuel in marine and air amphibious propulsion systems.

[0007] To solve its technical problems, the present invention proposes the following technical solutions: A marine and air amphibious fuel injection system based on methanol-activated aluminum-water fuel system. The fuel injection system is based on a prototype of a marine and air amphibious power system based on methanol-activated aluminum / water fuel system. The prototype includes: a fuel supply system (1) for storing and supplying methanol-activated aluminum fuel with adjustable aluminum particle concentration. It includes a high-concentration Al / MeOH fuel storage tank (1-1-1), a pure methanol-MeOH fuel storage tank (1-1-2), a mixing device (1-2), and a magnetic stirring device (1-3). The inlet of the mixing device (1-2) is connected to the high-concentration methanol-activated aluminum fuel storage tank (1-1-1) and the pure methanol storage tank (1-1-2), respectively. Its outlet outputs methanol-activated aluminum fuel with continuously adjustable aluminum particle concentration in the range of 2wt.% to 50wt.%. A fuel injection system (2), connected to the fuel supply system (1), is used to receive and inject the mixed methanol-activated aluminum fuel, and to introduce seawater or air as an oxidant; a combustion chamber (3), connected to the fuel injection system (2), is used to mix and burn the injected fuel with the oxidant; an adjustable tapered nozzle (4), connected to the outlet of the combustion chamber (3), has an adjustable outlet area; its features are: The fuel injection system (2) includes a needle injector having an inner flow channel (2-1), an outer flow channel (2-2), and a flow regulating unit (2-5) arranged coaxially. The inner flow channel (2-1) is located in the inner layer of the needle injector and is called the inner flow channel (2-1). The outer flow channel (2-2) is located in the outer layer of the needle injector and is called the outer flow channel (2-2). The flow regulating unit (2-5) is located at the outlet of the needle injector. The inner wall of 1) and the inner wall of the outer flow channel (2-2) are provided with multiple inner flow channel protrusions (2-3) and multiple outer flow channel protrusions (2-4) alternately along the axial direction. They are used to generate local eddies when the fuel flows through, so as to work together with the magnetic stirring device (1-3) to suppress the sedimentation of aluminum particles in the fuel. The flow rate adjustment unit (2-5) is used to adjust the flow rate ratio of the radial flow to the axial flow of the needle injector to achieve a thrust adjustment ratio of not less than 5:1.

[0008] Furthermore, the inner flow channel boss (2-3) and the outer flow channel boss (2-4) are arranged alternately along the axial direction, and the ratio of the axial distance (L) between adjacent bosses to the height (H) of the boss, L / H, is 1.5 to 4.

[0009] Furthermore, the cross-sectional shape of the inner flow channel boss (2-3) and the outer flow channel boss (2-4) is semi-circular or arc-shaped.

[0010] Furthermore, the fuel injection system (2) also includes an oxidant supply line connected to the needle injector, for switching between introducing seawater or air according to the working environment.

[0011] A method for injecting amphibious fuel based on a methanol-activated aluminum-water fuel system, characterized by the following steps: Step 1: Stir the fuel in the high-concentration Al / MeOH fuel storage tank (1-1-1) using the magnetic stirring device (1-3) of the fuel supply system (1), thereby inhibiting the settling of aluminum particles in the high-concentration Al / MeOH fuel storage tank (1-1-1); Step 2: The fuel output from the high-concentration Al / MeOH fuel storage tank (1-1-1) and the methanol MeOH fuel storage tank (1-1-2) is mixed in proportion through the mixing device (1-2) of the fuel supply system (1) to provide methanol-activated aluminum fuel with an adjustable aluminum particle concentration in the range of 2wt.% to 50wt.%. Step 3: Receive and inject the mixed methanol-activated aluminum fuel through the fuel injection system (2), and introduce seawater or air as an oxidant; Step 4: Adjust the flow ratio of radial flow to axial flow at the outlet of the needle injector using the flow adjustment unit (2-5) to achieve a thrust adjustment ratio of not less than 5:1.

[0012] Furthermore, in step three, the fuel injection system (2) receives and injects the mixed methanol-activated aluminum fuel, while simultaneously introducing seawater or air through the inner flow channel (2-1) and outer flow channel (2-2) of the needle injector (2). Multiple inner flow channel protrusions (2-3) and outer flow channel protrusions (2-4) on the inner walls of the inner flow channel (2-1) and outer flow channel (2-2) are alternately arranged along the axial direction to generate local eddies when the fuel flows through, which, together with the magnetic stirring device (1-3), suppress the sedimentation of aluminum particles in the fuel.

[0013] Furthermore, the inner flow channel boss (2-3) and the outer flow channel boss (2-4) are arranged alternately along the axial direction, and the ratio of the axial distance (L) between adjacent bosses to the height (H) of the boss, L / H, is 1.5 to 4.

[0014] Furthermore, the cross-sectional shape of the inner flow channel boss (2-3) and the outer flow channel boss (2-4) is semi-circular or arc-shaped.

[0015] Furthermore, in step three, the fuel injection system (2) switches between introducing seawater or air as the oxidant through the oxidant supply pipeline, depending on the working environment.

[0016] Furthermore, the fuel supply system (1) includes a high-concentration Al / MeOH fuel storage tank (1-1-1) and a pure methanol MeOH fuel storage tank (1-1-2), a mixing device (1-2), and a magnetic stirring device (1-3); the high-concentration Al / MeOH fuel storage tank (1-1-1) and the pure methanol MeOH fuel storage tank (1-1-2) divide the Al / MeOH fuel inlet into two parts, one for high-concentration Al / MeOH fuel (wt.%>80 wt.%) and the other for pure methanol (MeOH) fuel. In order to meet the requirements of different working conditions for thrust on flow rate and fuel energy density, the flow ratio of high-concentration Al / MeOH fuel and MeOH fuel is adjusted to realize the underwater power fuel subsystem and the low-altitude power fuel subsystem; The mixing device (1-2) is connected to the high-concentration Al / MeOH fuel storage tank (1-1-1) and the pure methanol MeOH fuel storage tank (1-1-2) respectively, and is used to mix the fuel output from the two in proportion to provide methanol-activated aluminum fuel with an adjustable aluminum particle concentration in the range of 2wt.% to 50wt.%. The magnetic stirring device (1-3) is installed inside the high-concentration Al / MeOH fuel storage tank (1-1-1) to suppress the sedimentation and agglomeration of metal fuel particles inside the tank.

[0017] 1. Effectively improves the uniformity and supply stability of high-concentration aluminum / methanol fuel. Addressing the problem of aluminum particles easily settling and agglomerating, this invention solves the problem through a combination of "active stirring" and "passive disturbance": a magnetic stirring device (1-3) is installed inside the high-concentration fuel storage tank (1-1-1) to achieve macroscopic active homogenization of the fuel, fundamentally suppressing settling within the tank. Alternating bosses (2-3, 2-4) are set on the inner and outer flow channel walls of the needle-plug injector, generating local eddies as the fuel flows through, microscopically shearing and redispersing the particles, effectively preventing agglomeration and blockage in the pipeline and injector. These two levels of measures jointly ensure the uniformity of fuel composition and stable flow throughout the storage, transportation, and injection process, laying the foundation for efficient and reliable combustion.

[0018] 2. Stable and efficient atomization and combustion are achieved within a wide thrust adjustment range. To address the contradiction of decreased atomization quality during deep thrust adjustment, this invention endows the needle-plug injector with excellent adaptive adjustment capabilities: the needle-plug injector has switchable injection modes such as radial orifice / axial slot and radial orifice / axial orifice, and can select the optimal atomization structure according to different flow conditions. The flow adjustment unit (2-5) precisely controls the flow ratio of radial and axial flow, and in conjunction with the needle plug structure, generates controllable swirl, thereby flexibly adjusting the spray cone angle and mixing state. This allows the system to maintain good fuel atomization quality and mixing effect within a wide thrust adjustment ratio of no less than 5:1, ensuring combustion stability and power control accuracy under all operating conditions.

[0019] 3. Significantly enhances the adaptability of the power system to multiple working medium oxidants (seawater / air). Addressing the challenge of significant differences in oxidant properties under cross-medium operating conditions, the fuel injection system of this invention exhibits high flexibility and robustness: seawater or air can be quickly switched in via the oxidant supply pipeline.

[0020] The injector can switch injection modes and adjust swirl intensity accordingly, thereby optimizing the spray pattern and mixing process for different oxidants (such as the density and salinity of seawater and the density and composition of air). This design, which combines "flexible oxidant switching" with "intelligent matching of fuel injection parameters," effectively solves the problem of fuel adaptability in cross-domain operations, and significantly improves the combustion organization and overall efficiency of the power system in both seawater and air media. Attached Figure Description

[0021] Figure 1a This is a schematic diagram of the prototype of the amphibious propulsion system based on methanol-activated aluminum water system fuel for this invention. Figure 1b This is a schematic diagram of the prototype of the amphibious propulsion system based on methanol-activated aluminum water system of the present invention. Figure 2 ; Figure 1cThis is a schematic diagram of the application of the prototype of the amphibious propulsion system based on methanol-activated aluminum water system fuel of the present invention to an amphibious propulsion system. Figure 2 This is a schematic diagram of an existing needle-type nozzle injector. Figure 3 This is a schematic diagram of the improved fuel supply system of the present invention; Figure 4 This is a schematic diagram of the improved fuel injection system of the present invention; Figure 5 This is a diagram showing the internal structure of the mixing device of the present invention; Figure 6 This is a flowchart of the amphibious fuel injection method of the present invention.

[0022] In the diagram, 1: Fuel supply system; 1-1-1: High-concentration Al / MeOH fuel storage tank; 1-1-2: Pure methanol-MeOH fuel storage tank; 1-2: Mixing device; 1-3: Magnetic stirring device; 2: Fuel injection system; 2-1: Inner flow channel; 2-2: Outer flow channel; 2-3: Inner flow channel boss; 2-4: Outer flow channel boss; 3: Combustion chamber; 4: Adjustable tapered nozzle. Detailed Implementation

[0023] The innovations of this invention are: 1. Innovative fuel preparation. Addressing the issue that underwater propulsion requires high-energy-density fuels (such as those containing metal particles), while aerial flight may require different concentrations or pure fuels for optimal performance, this invention employs: ① a dual-fuel tank system: one storing a high-concentration aluminum / methanol slurry, and the other storing pure methanol. ② Equipped with an online dynamic mixer, enabling real-time proportional mixing of the two fuels. This achieves real-time, continuous, and precise adjustment of the aluminum particle concentration in the fuel within the range of 2 wt.% to 50 wt.%. This allows the system to quickly switch fuel formulations, precisely matching the different operational requirements of high energy density underwater and high efficiency in the air, ensuring mission continuity and high adaptability.

[0024] 2. Fuel Stability Innovation. Addressing the issue of metal particles (such as aluminum) easily settling and agglomerating in liquid fuels, leading to uneven delivery, injection blockage, and unstable combustion, a magnetic stirring device is integrated into the high-concentration fuel tank for continuous active homogenization. Inside the core needle-plug injector, a staggered boss flow channel design utilizes localized eddies generated as the fluid flows through for secondary enhanced mixing. This effectively suppresses the settling and agglomeration of aluminum particles throughout the entire process (storage, delivery, and injection), ensuring fuel homogeneity and stability and laying a solid foundation for subsequent stable and efficient combustion.

[0025] 3. Thrust Adjustment and Cross-Media Adaptability Innovation: Utilizing a needle-bolt injector. The injector can switch between introducing seawater or air as the oxidizer / working medium depending on the environment. By axially moving the needle, the injection mode can be flexibly switched (such as radial orifice / axial slot or a combination of radial orifice / axial orifice) to adapt to the rheological and combustion characteristics of different media, water and air. Combined with an independent flow regulation unit and controllable swirl design, the radial and axial flow ratio and mixing intensity are precisely controlled. This achieves a wide thrust adjustment range of >5:1, greatly improving the controllability of power output. Intelligent switching and compatibility between water and air working media are realized, truly meeting the core power requirements for cross-domain flight.

[0026] The design principle of this invention is as follows: I. Solution to the difficulties in switching fuel systems and controlling concentration: Existing technologies struggle to achieve rapid and precise switching between underwater (high-concentration aluminum fuel) and low-altitude (low-concentration aluminum fuel) operating conditions, and the aluminum particle concentration adjustment range is narrow and lacks precision. Therefore, this invention adopts a "dual-tank mixing - precisely adjustable concentration" design concept: ① Independent supply from two tanks: Independent high-concentration aluminum / methanol fuel tank 1-1-1 and pure methanol fuel tank 1-1-2 are set up, providing a basis for flexible fuel concentration adjustment and overcoming the concentration limitations of a single fuel tank. ② Online dynamic mixing: Through parallel pipelines and high-precision flow control valves, combined with mixing device 1-2 (such as an online dynamic mixer), real-time, proportional mixing of the two fuels is achieved, thereby dynamically adjusting the fuel concentration. ③ Wide-range continuous adjustment: Wide, continuous, and precise adjustment of aluminum particle concentration is achieved within the range of 2wt.% to 50wt.%. By using real-time dual-fuel ratios, the energy density requirements of different operating conditions can be precisely matched. For example, in underwater mode, the proportion of aluminum fuel is adjusted to 40%–50%; in low-altitude mode, the proportion of aluminum fuel is reduced to below 2%. The effect is to ensure rapid and smooth switching between underwater and aerial modes, significantly improving the continuity and mission adaptability of the system across different domains.

[0027] II. Solution to the Problem of Maintaining Uniform Suspension of Metal Particles: Since aluminum particles have a much higher density than methanol, they are prone to settling and agglomeration during storage and transportation, leading to uneven fuel component distribution and affecting combustion stability and efficiency. Therefore, this invention adopts a "active stirring-vortex synergistic suspension" design concept: ① Active Homogenization (Inside the Tank): A magnetic stirring device 1-3 is integrated into the high-concentration fuel storage tank 1-1-1 to achieve continuous and active homogenization of the fuel, effectively suppressing particle settling and agglomeration within the tank. ② Vortex-Enhanced Mixing (During Transportation): An alternating boss flow channel design is adopted inside the needle injector (inner flow channel boss 2-3 and outer flow channel boss 2-4 are arranged alternately along the axial direction), utilizing the local vortices generated by the flow through the bosses to further enhance mixing. By optimizing the boss spacing and height ratio (… L / H= 1.5–4) and cross-sectional shape (semi-circular / arc) maximize the eddy current effect and prevent aluminum particles from agglomerating and settling during transportation. Effectively suppresses the settling and agglomeration of aluminum particles throughout the storage and transportation process, ensuring the uniformity and stability of fuel components, thereby improving engine operating stability and combustion efficiency.

[0028] III. Thrust Adjustment Design Principles. ① Flow Ratio Adjustment: The flow ratio of radial and axial flow is precisely controlled through the integrated flow adjustment unit of the needle-bolt injector. ② Injection Mode Switching: It features switchable injection modes: ② Radial Orifice / Axial Slit: Suitable for high flow conditions; ③ Radial Orifice / Axial Orifice: Suitable for low flow conditions. Combined with controllable swirl adjustment of the fuel spray cone angle, active optimization of spray characteristics is achieved. ④ Wide-Range Thrust Adjustment: By precisely controlling the needle-bolt position to adjust the flow channel area and flow ratio, a wide-range thrust adjustment of no less than 5:1 is achieved, improving the combustion organization and efficiency of the engine under different operating conditions and environments.

[0029] In summary, this invention systematically solves the key technical challenges of cross-domain switching, uniform and stable supply, and wide-range thrust adjustment in amphibious propulsion systems by integrating three core technologies: "dual-tank mixing - precise concentration adjustment", "active stirring - vortex-coordinated suspension", and "needle plug adjustment - multi-mode injection". It achieves efficient and stable switching between underwater and air working modes and improves overall performance.

[0030] Based on the above principles, this invention designs an amphibious fuel injection system for sea and air based on a methanol-activated aluminum-water fuel system, such as... Figure 1a , 1b As shown in Figures 1c, 2, 3, and 4, this amphibious fuel injection system is based on a prototype of a sea-air amphibious propulsion system using a methanol-activated aluminum / water fuel system. The prototype is as follows... Figure 1a , 1b As shown, the system includes: a fuel supply system 1 for storing and supplying methanol-activated aluminum fuel with adjustable aluminum particle concentration, comprising a high-concentration Al / MeOH fuel storage tank 1-1-1, a pure methanol / MeOH fuel storage tank 1-1-2, a mixing device 1-2, and a magnetic stirring device 1-3. The inlet of the mixing device 1-2 is connected to both the high-concentration methanol-activated aluminum fuel storage tank 1-1-1 and the pure methanol storage tank 1-1-2, and its outlet outputs methanol-activated aluminum fuel with an aluminum particle concentration continuously adjustable from 2 wt.% to 50 wt.%. A fuel injection system 2, connected to the fuel supply system 1, for receiving and injecting the mixed methanol-activated aluminum fuel and introducing seawater or air as an oxidant. A combustion chamber 3, connected to the fuel injection system 2, for mixing and burning the injected fuel and oxidant. An adjustable tapered nozzle 4, connected to the outlet of the combustion chamber 3, with an adjustable outlet area. Its features are as follows: the fuel injection system 2 includes a needle injector, which has an inner flow channel 2-1, an outer flow channel 2-2, and a flow regulating unit 2-5 arranged coaxially; the inner flow channel 2-1 is located in the inner layer of the needle injector, and the outer flow channel 2-2 is located in the outer layer of the needle injector, and the flow regulating unit 2-5 is located at the outlet of the needle injector; multiple inner flow channel protrusions 2-3 and multiple outer flow channel protrusions 2-4 are alternately arranged along the axial direction on the inner wall of the inner flow channel 2-1 and the inner wall of the outer flow channel 2-2, which are used to generate local eddies when the fuel flows through, so as to work with the magnetic stirring device 1-3 to suppress the sedimentation of aluminum particles in the fuel; the flow regulating unit 2-5 is used to adjust the flow ratio of the radial flow to the axial flow of the needle injector to achieve a thrust regulation ratio of not less than 5:1.

[0031] Supplementary Note 1: For detailed information on the structure of the flow regulation units 2-5 mentioned above, please refer to the following website: The details of https: / / arc.aiaa.org / doi / 10.2514 / 6.2000-3871 will not be elaborated upon here.

[0032] The inner flow channel protrusion 2-3 and the outer flow channel protrusion 2-4 are arranged alternately along the axial direction, and the ratio of the axial distance (L) between adjacent protrusions to the height (H) of the protrusion, L / H, is 1.5 to 4.

[0033] The cross-sectional shape of the inner flow channel boss (2-3) and the outer flow channel boss 2-4 is semi-circular or arc-shaped.

[0034] The fuel injection system (2) also includes an oxidant supply line connected to the needle injector, for switching between introducing seawater or air according to the working environment.

[0035] A method for injecting amphibious fuel based on a methanol-activated aluminum-water fuel system, characterized by the following steps: Step 1: Stir the fuel in the high-concentration Al / MeOH fuel storage tank 1-1-1 using the magnetic stirring device 1-3 of the fuel supply system 1, thereby inhibiting the sedimentation of aluminum particles in the high-concentration Al / MeOH fuel storage tank 1-1-1. Step 2: The fuel output from the high-concentration Al / MeOH fuel storage tank 1-1-1 and the methanol-MeOH fuel storage tank 1-1-2 are mixed in proportion through the mixing device 1-2 of the fuel supply system 1 to provide methanol-activated aluminum fuel with an adjustable aluminum particle concentration in the range of 2wt.% to 50wt.%. Step 3: Receive and inject the mixed methanol-activated aluminum fuel through fuel injection system 2, and introduce seawater or air as an oxidant; Step 4: Adjust the flow ratio of radial flow to axial flow at the outlet of the needle injector using the flow adjustment unit 2-5 to achieve a thrust adjustment ratio of not less than 5:1.

[0036] In step three, the fuel injection system 2 receives and injects the mixed methanol-activated aluminum fuel, while simultaneously introducing seawater or air through the inner channel 2-1 and outer channel 2-2 of the needle injector 2. Multiple inner channel protrusions 2-3 and outer channel protrusions 2-4 on the inner walls of the inner channel 2-1 and outer channel 2-2 are alternately arranged along the axial direction to generate local eddies when the fuel flows through, which, together with the magnetic stirring device 1-3, suppress the sedimentation of aluminum particles in the fuel.

[0037] The inner flow channel protrusion 2-3 and the outer flow channel protrusion 2-4 are arranged alternately along the axial direction, and the ratio of the axial distance (L) between adjacent protrusions to the height (H) of the protrusion, L / H, is 1.5 to 4.

[0038] The cross-sectional shape of the inner flow channel boss 2-3 and the outer flow channel boss 2-4 is semi-circular or arc-shaped.

[0039] In step three, the fuel injection system 2 switches between introducing seawater or air as the oxidant through the oxidant supply pipeline, depending on the working environment.

[0040] The fuel supply system 1 includes a high-concentration Al / MeOH fuel storage tank 1-1-1 and a pure methanol-MeOH fuel storage tank 1-1-2, a mixing device 1-2, and a magnetic stirring device 1-3. The high-concentration Al / MeOH fuel storage tank 1-1-1 and the pure methanol-MeOH fuel storage tank 1-1-2 divide the Al / MeOH fuel inlet into two parts: one for high-concentration Al / MeOH fuel (wt.%>80 wt.%) and the other for pure methanol (MeOH) fuel. To meet the requirements of different operating conditions for varying thrust and flow rate and fuel energy density, the flow rate ratio of high-concentration Al / MeOH fuel and MeOH fuel is adjusted to realize the underwater power fuel subsystem and the low-altitude power fuel subsystem. The mixing device 1-2 is connected to the high-concentration Al / MeOH fuel storage tank 1-1-1 and the pure methanol MeOH fuel storage tank 1-1-2 respectively, and is used to mix the fuel output from the two in proportion to provide methanol-activated aluminum fuel with an adjustable aluminum particle concentration in the range of 2wt.% to 50wt.%. The magnetic stirring device 1-3 is installed inside the high-concentration Al / MeOH fuel storage tank 1-1-1 to suppress the sedimentation and agglomeration of metal fuel particles inside the tank.

[0041] Supplementary Note 2: Explanation of the above "Fuel Supply System 1": When the underwater power fuel subsystem is implemented, the fuel supply system 1 mixes high-concentration Al / MeOH fuel and pure methanol MeOH fuel through mixing device 1-2, adjusting the proportion of Al fuel in methanol MeOH from >80% to 40 to 50%. At this time, the proportion of methanol MeOH in Al fuel is 50 to 40%.

[0042] When the low-altitude power fuel subsystem is implemented, the fuel supply system 1 mixes high-concentration Al / MeOH fuel and pure methanol MeOH fuel through mixing device 1-2, adjusting the proportion of Al fuel in methanol MeOH from >80% to <2%. At this time, the proportion of methanol MeOH in Al fuel is greater than 98%.

[0043] The mixing device 1-2 includes: at least two flow control valves, which respectively control the fuel flow rate output from the high-concentration Al / MeOH fuel storage tank 1-1-1 and the pure methanol MeOH fuel storage tank 1-1-2; a mixing chamber for receiving and mixing the fuel from the flow control valves; utilizing the principle of jet collision to promote mixing, the high-concentration Al / MeOH fuel and the pure methanol MeOH fuel are fully mixed and then flow out from the right outlet; a concentration sensor is arranged at the outlet to detect the aluminum particle concentration in the mixed fuel, and when the concentration meets the operating requirements, the right valve is controlled to open.

[0044] The flow control valve is a servo valve, which can achieve fast and precise flow regulation.

[0045] By combining CFD simulations with visualization experiments, the stirring intensity and mixing method were optimized to suppress particle sedimentation and localized accumulation. Online sampling and concentration testing were used to verify fuel homogeneity and supply stability under different supply flow rates and concentrations, establishing an engineering method for the continuous and stable supply of high-concentration Al / MeOH fuel.

[0046] Supplementary Explanation 3: Explanation of the above-mentioned "combustion chamber 3": The combustion chamber and nozzle propulsion system can refer to mature rocket engine technology. This invention focuses on the research of the supply system and injection system of (Al / MeOH) / water system self-ignition fuel.

[0047] Supplementary Explanation 4: Explanation of the aforementioned adjustable tapered nozzle 4: like Figure 1a , 1bAs shown, the adjustable tapered nozzle 4 has a larger nozzle flow area in underwater mode to adapt to the high back pressure environment and improve the mass flow rate; and a smaller nozzle flow area in low-altitude mode to maintain a higher jet velocity and propulsion efficiency. The adjustable tapered nozzle 4 is configured to allow the prototype to operate stably for more than 10 seconds in both underwater and low-altitude conditions by adjusting its exit area.

[0048] It should be emphasized that the above specific embodiments are merely explanations of the present invention and are not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to the above embodiments without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. An amphibious fuel injection system based on a methanol-activated aluminum / water fuel system, the fuel injection system being based on a prototype of an amphibious propulsion system using a methanol-activated aluminum / water fuel system, the prototype comprising: A fuel supply system (1) is used to store and supply methanol-activated aluminum fuel with adjustable aluminum particle concentration. It includes a high-concentration Al / MeOH fuel storage tank (1-1-1), a pure methanol / MeOH fuel storage tank (1-1-2), a mixing device (1-2), and a magnetic stirring device (1-3). The inlet of the mixing device (1-2) is connected to both the high-concentration methanol-activated aluminum fuel storage tank (1-1-1) and the pure methanol storage tank (1-1-2), and its outlet outputs methanol-activated aluminum fuel with an aluminum particle concentration continuously adjustable from 2 wt.% to 50 wt.%. A fuel injection system (2) is connected to the fuel supply system (1) and is used to receive and inject the mixed methanol-activated aluminum fuel, and introduce seawater or air as an oxidant. A combustion chamber (3) is connected to the fuel injection system (2) and is used to mix and burn the injected fuel with the oxidant. An adjustable tapered nozzle (4) is connected to the outlet of the combustion chamber (3), and its outlet area is adjustable. The system is characterized by: The fuel injection system (2) includes a needle injector having an inner flow channel (2-1), an outer flow channel (2-2), and a flow regulating unit (2-5) arranged coaxially. The inner flow channel (2-1) is located in the inner layer of the needle injector and is called the inner flow channel (2-1). The outer flow channel (2-2) is located in the outer layer of the needle injector and is called the outer flow channel (2-2). The flow regulating unit (2-5) is located at the outlet of the needle injector. The inner wall of 1) and the inner wall of the outer flow channel (2-2) are provided with multiple inner flow channel protrusions (2-3) and multiple outer flow channel protrusions (2-4) alternately along the axial direction. They are used to generate local eddies when the fuel flows through, so as to work together with the magnetic stirring device (1-3) to suppress the sedimentation of aluminum particles in the fuel. The flow rate adjustment unit (2-5) is used to adjust the flow rate ratio of the radial flow to the axial flow of the needle injector to achieve a thrust adjustment ratio of not less than 5:

1.

2. The amphibious fuel injection system based on methanol-activated aluminum-water fuel system according to claim 1, characterized in that, The inner flow channel boss (2-3) and the outer flow channel boss (2-4) are arranged alternately along the axial direction, and the ratio of the axial distance (L) between adjacent bosses to the height (H) of the boss, L / H, is 1.5 to 4.

3. An amphibious fuel injection system based on a methanol-activated aluminum-water fuel system according to claim 1 or 4, characterized in that, The cross-sectional shape of the inner flow channel boss (2-3) and the outer flow channel boss (2-4) is semi-circular or arc-shaped.

4. The amphibious fuel injection system based on methanol-activated aluminum-water fuel system according to claim 1, characterized in that, The fuel injection system (2) also includes an oxidant supply line connected to the needle injector, for switching between introducing seawater or air according to the working environment.

5. A method for injecting amphibious fuel based on a methanol-activated aluminum-water fuel system, according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Stir the fuel in the high-concentration Al / MeOH fuel storage tank (1-1-1) using the magnetic stirring device (1-3) of the fuel supply system (1), thereby inhibiting the settling of aluminum particles in the high-concentration Al / MeOH fuel storage tank (1-1-1); Step 2: The fuel output from the high-concentration Al / MeOH fuel storage tank (1-1-1) and the methanol MeOH fuel storage tank (1-1-2) is mixed in proportion through the mixing device (1-2) of the fuel supply system (1) to provide methanol-activated aluminum fuel with an adjustable aluminum particle concentration in the range of 2wt.% to 50wt.%. Step 3: Receive and inject the mixed methanol-activated aluminum fuel through the fuel injection system (2), and introduce seawater or air as an oxidant; Step 4: Adjust the flow ratio of radial flow to axial flow at the outlet of the needle injector using the flow adjustment unit (2-5) to achieve a thrust adjustment ratio of not less than 5:

1.

6. The amphibious fuel injection method based on methanol-activated aluminum-water fuel system according to claim 5, characterized in that, In step three, the fuel injection system (2) receives and injects the mixed methanol-activated aluminum fuel, and at the same time introduces seawater or air through the inner flow channel (2-1) and outer flow channel (2-2) of the needle injector (2). Multiple inner flow channel protrusions (2-3) and outer flow channel protrusions (2-4) on the inner walls of the inner flow channel (2-1) and outer flow channel (2-2) are alternately arranged along the axial direction to generate local eddies when the fuel flows through, which work together with the magnetic stirring device (1-3) to suppress the sedimentation of aluminum particles in the fuel.

7. A method for injecting amphibious fuel based on a methanol-activated aluminum-water fuel system according to claim 6, characterized in that, The inner flow channel boss (2-3) and the outer flow channel boss (2-4) are arranged alternately along the axial direction, and the ratio of the axial distance (L) between adjacent bosses to the height (H) of the boss, L / H, is 1.5 to 4.

8. A method for injecting amphibious fuel based on a methanol-activated aluminum-water fuel system according to claim 6 or 7, characterized in that, The cross-sectional shape of the inner flow channel boss (2-3) and the outer flow channel boss (2-4) is semi-circular or arc-shaped.

9. A method for injecting amphibious fuel based on a methanol-activated aluminum-water fuel system according to claim 5, characterized in that, In step three, the fuel injection system (2) switches between introducing seawater or air as oxidant through the oxidant supply pipeline, depending on the working environment.

10. A method for injecting amphibious fuel based on a methanol-activated aluminum-water fuel system according to claim 5, characterized in that, The fuel supply system (1) includes a high-concentration Al / MeOH fuel storage tank (1-1-1) and a pure methanol MeOH fuel storage tank (1-1-2), a mixing device (1-2), and a magnetic stirring device (1-3). The high-concentration Al / MeOH fuel storage tank (1-1-1) and the pure methanol MeOH fuel storage tank (1-1-2) divide the Al / MeOH fuel inlet into two parts: one is high-concentration Al / MeOH fuel (wt.% > 80 wt.%), and the other is pure methanol (MeOH) fuel. In order to meet the requirements of different operating conditions for thrust on flow rate and fuel energy density, the flow ratio of high-concentration Al / MeOH fuel and MeOH fuel is adjusted to realize the underwater power fuel subsystem and the low-altitude power fuel subsystem. The mixing device (1-2) is connected to the high-concentration Al / MeOH fuel storage tank (1-1-1) and the pure methanol MeOH fuel storage tank (1-1-2) respectively, and is used to mix the fuel output from the two in proportion to provide methanol-activated aluminum fuel with an adjustable aluminum particle concentration in the range of 2wt.% to 50wt.%. The magnetic stirring device (1-3) is installed inside the high-concentration Al / MeOH fuel storage tank (1-1-1) to suppress the sedimentation and agglomeration of metal fuel particles inside the tank.

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