Hydrogen filling nozzle

Abstract

The invention relates to the technical field of high-pressure hydrogen storage bottles, in particular to a hydrogen filling nozzle which comprises an injection pipe communicated with a valve inner channel and used for circulation of high-pressure hydrogen and an air nozzle communicated with the injection pipe, formed at the front end of the injection pipe and bent towards an inner container of a bottle body. The connecting line of the circle centers of the end faces of the two ends of the bottle body is a central longitudinal axis, a preset included angle ranging from 5 degrees to 15 degrees is formed between the central line of the air nozzle and the central longitudinal axis, the flowing vortex and turbulence intensity is weakened by guiding high-pressure hydrogen to diffuse along the inner wall of the inner container of the bottle body, and the flowing vortex and turbulence intensity is reduced by guiding the high-pressure hydrogen to evenly diffuse along the inner wall of the bottle body. The device weakens flowing vortex and turbulence intensity, avoids local gas compression heating, further inhibits formation of local temperature hot spots on the surface of the inner container, solves the problem that turbulence and temperature hot spots are easy to form during hydrogen filling in the prior art, and improves the safety and durability of the high-pressure hydrogen storage system.

Description

Technical Field

[0001] This invention relates to the field of high-pressure hydrogen storage cylinder technology, and in particular to a hydrogen refueling nozzle. Background Technology

[0002] With the rapid development of the hydrogen fuel cell vehicle industry, the high-pressure hydrogen storage system, as a core component, directly affects the vehicle's operational reliability due to its safety and filling performance. A high-pressure hydrogen storage cylinder in a hydrogen fuel cell vehicle typically includes a cylinder body with an inner liner and an outer shell, and a valve sealed at the cylinder opening. This valve contains a one-way valve and an internal channel for hydrogen flow. The hydrogen refueling nozzle, as a key component of the valve, not only performs the basic function of hydrogen refueling but also ensures the stability of hydrogen flow and temperature uniformity within the cylinder.

[0003] During high-pressure hydrogen refueling, hydrogen enters the cylinder through the nozzle at super-Mach speeds. Existing hydrogen refueling nozzles primarily focus on the refueling function, neglecting fluid dynamics optimization for key parameters such as injection angle and installation position. This leads to strong turbulence and flow vortices upon the high-speed hydrogen entering the cylinder. This results in uneven hydrogen distribution within the cylinder and compresses residual gas at the rear, causing localized heating and creating significant temperature hotspots. These hotspots generate substantial thermal stress, directly damaging the structural integrity of the hydrogen storage cylinder's inner liner, potentially leading to melting and premature fatigue failure, drastically shortening its lifespan. This has become a critical technical challenge hindering the safety and durability of high-pressure hydrogen storage systems. Furthermore, an inadequate gap design between the one-way valve and the nozzle exacerbates fluid disturbances, further worsening the problems of turbulence and uneven temperature distribution.

[0004] Therefore, it is necessary to develop a hydrogen refueling nozzle that can suppress turbulence generation and temperature hotspot formation in order to solve the safety hazards of existing technologies. Summary of the Invention

[0005] This application provides a hydrogen refueling nozzle that solves the problem of turbulence and temperature hotspots easily forming during hydrogen refueling in the prior art, thereby improving the safety and durability of high-pressure hydrogen storage systems.

[0006] This application provides a hydrogen refueling nozzle for use as a valve on the mouth of a high-pressure hydrogen storage cylinder in a hydrogen fuel cell vehicle. The high-pressure hydrogen storage cylinder includes a cylinder body with an inner liner and an outer shell, and a valve sealed at the mouth of the cylinder body. The valve includes a valve body, a one-way valve disposed within the valve body, and an internal channel for hydrogen flow. The hydrogen refueling nozzle includes an injection pipe communicating with the internal channel for high-pressure hydrogen flow, and a nozzle connected to the injection pipe and formed at the front end of the injection pipe and bent toward the inner liner of the cylinder body. The line connecting the centers of the two end faces of the cylinder body is the central longitudinal axis, and the centerline of the nozzle forms a preset angle of 5°-15° with the central longitudinal axis. By guiding the high-pressure hydrogen to diffuse along the inner wall of the inner liner of the cylinder body, the flow vortex and turbulence intensity are weakened.

[0007] Furthermore, the centerline of the injection pipe is offset radially from the central longitudinal axis.

[0008] Furthermore, the distance between the centerline of the injection pipe and the central longitudinal axis is the eccentric distance, and the value of the eccentric distance ranges from 1mm to 10mm.

[0009] Furthermore, one end of the injection pipe is provided with an external thread structure, and the end of the valve channel of the bottle mouth valve is provided with a matching internal thread structure. The injection pipe is detachably and fixedly assembled with the bottle mouth valve through a threaded connection. The hydrogen filling nozzle is a replaceable structure, and the hydrogen filling nozzle with a corresponding preset included angle and eccentric distance can be replaced according to the length and inner diameter of the bottle body.

[0010] Furthermore, the injection pipe is provided with a connecting pipe, which is arranged opposite to the gas flow channel in the one-way valve, and an airflow gap is formed between the connecting pipe and the gas flow channel, the airflow gap having a longitudinal dimension.

[0011] Furthermore, the longitudinal dimension is 2 mm, and the longitudinal dimension remains constant throughout the entire process of the one-way valve reciprocating along the central longitudinal axis.

[0012] Furthermore, the cross-sectional shape of the jet nozzle is circular, and the inner diameter of the jet nozzle is 2mm to 8mm.

[0013] Furthermore, the preset included angle and eccentric distance are obtained through computational fluid dynamics simulation optimization, and the simulation boundary conditions meet the requirements of a temperature range of 40°C to 85°C and a maximum injection pressure of 875 bar.

[0014] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: 1. This invention combines a preset included angle of 5°-15° determined by CFD simulation optimization with a radial eccentric structure, which weakens the flow vortex and turbulence intensity during high-pressure hydrogen refueling. This effectively solves the problems of uneven hydrogen distribution and local compression heating caused by turbulence in traditional nozzles, avoids the formation of hot spots on the inner liner surface, reduces the damage of thermal stress to the structural integrity of the hydrogen storage cylinder, extends the service life of the high-pressure hydrogen storage cylinder, and improves the safety of the hydrogen refueling process.

[0015] 2. Under the operating conditions of a 50L hydrogen storage cylinder and a hydrogen filling flow rate of 120g / s, the optimal angle design of 5°-15° in this invention results in a significantly higher internal pressure when the hydrogen storage cylinder temperature rises to 85°C compared to traditional nozzles. According to the gas state equation, higher pressure corresponds to a larger hydrogen filling capacity. At the same time, this angle range achieves the best balance between flow time and pressure stability, avoiding inefficient time consumption while ensuring filling capacity. Compared with traditional products such as Lechler nozzles and Mercedes star nozzles, both filling efficiency and filling capacity are significantly improved.

[0016] 3. The present invention has a connecting pipe inside the injection pipe, and an airflow gap is formed between the connecting pipe and the gas flow channel. The airflow gap has a longitudinal dimension and is optimized by fluid dynamics analysis to avoid the generation of eddy current disturbances in the fluid at the gap, further helping to suppress the generation of turbulence and ensure smooth and stable hydrogen flow. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the high-pressure hydrogen storage cylinder of the hydrogen fuel cell vehicle in Embodiment 1 of this application; Figure 2 In Embodiment 1 of this application Figure 1 A magnified view of part A in the image; Figure 3 This is a schematic diagram of the installation structure of the bottle valve and hydrogen refueling nozzle in Embodiment 1 of this application; Figure 4 This is a cross-sectional schematic diagram of the hydrogen refueling nozzle in Embodiment 1 of this application; Figure 5 This is a schematic diagram of the hydrogen refueling nozzle in Embodiment 1 of this application.

[0018] Among them, 1. Bottle body; 101. Inner liner; 102. Outer shell; 2. Bottle valve; 201. Valve internal channel; 202. One-way valve; 203. Connecting pipe; 3. Hydrogen filling nozzle; 301. Injection pipe; 302. Injection nozzle. Detailed Implementation

[0019] In high-pressure hydrogen refueling scenarios for hydrogen fuel cell vehicles, the core technical challenge lies in the structural design flaws of traditional hydrogen refueling nozzles. When hydrogen gas traveling at super-Mach speeds enters a 50L hydrogen storage cylinder through the nozzle, the lack of hydrodynamic optimization of the injection angle and installation position easily leads to strong turbulence and flow vortices. This results in uneven hydrogen distribution within the cylinder, and residual gas after compression causes localized heating, creating significant temperature hotspots. This problem directly causes thermal stress accumulation within the hydrogen storage cylinder liner, posing a safety hazard of liner melting and premature cylinder fatigue failure, significantly shortening its lifespan. Furthermore, traditional nozzles have poor versatility, making them difficult to adapt to hydrogen storage cylinders of different lengths and inner diameters, further limiting the practicality and safety of high-pressure hydrogen storage systems.

[0020] To address the aforementioned core issues, this application provides a hydrogen refueling nozzle based on fluid dynamics optimization. Its core technical solution revolves around the precise design of key structural parameters: through computational fluid dynamics (CFD) simulation combined with analysis of key parameters such as Reynolds number, Mach number, and turbulence intensity, a design is determined that combines a 5°-15° injection angle with a radially eccentric structure to guide high-pressure hydrogen to diffuse uniformly along the inner wall of the cylinder; simultaneously, a replaceable threaded connection structure is adopted, allowing for flexible matching of nozzles with corresponding parameters based on the length and inner diameter of the hydrogen storage cylinder, and optimizing the 2mm constant longitudinal gap between the outlet pipe and the connecting pipe of the one-way valve.

[0021] This technical solution directly achieves the core objectives of turbulence suppression and temperature hotspot control: the optimal injection angle of 5°-15° combined with the eccentric design significantly weakens the vortex intensity and turbulence effect during high-pressure hydrogen flow, avoids local gas compression heating, and makes the surface temperature distribution of the hydrogen storage cylinder's inner liner more uniform, eliminating the formation of temperature hotspots. This design effectively reduces the damage of thermal stress to the structural integrity of the hydrogen storage cylinder and avoids the risk of inner liner melting. Simulation verification shows that under the conditions of a 50L volume cylinder and a filling flow rate of 120g / s, when the cylinder temperature rises to 85℃, the internal pressure is significantly higher than that of traditional products such as Lechler nozzles and Mercedes star nozzles, providing a key guarantee for the structural safety and long-term stable operation of the cylinder.

[0022] Based on this, the technical solution of this application also achieves multiple improvements in filling performance, versatility and adaptability to working conditions: the optimal angle design suppresses turbulence while achieving a balance between flow time and pressure stability, which not only increases the hydrogen filling capacity but also ensures refueling efficiency; simulation optimization based on the continuity equation and the Navier-Stokes equation for compressible flow, as well as boundary condition settings that comply with the SAE J2601 hydrogen refueling protocol, ensures that the nozzle can adapt to the harsh working conditions of high-pressure hydrogen storage in vehicles and has broad application value.

[0023] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0024] Example 1 Reference Figure 1 and Figure 2 A hydrogen refueling nozzle is used for the valve at the mouth of a high-pressure hydrogen storage cylinder in a hydrogen fuel cell vehicle. In this embodiment, the on-board hydrogen storage system of the hydrogen fuel cell vehicle uses a 6061-T6 high-strength aluminum alloy inner liner with a thickness of only 2-5mm. The outer shell is reinforced with T700 grade or higher carbon fiber through a wet winding process. The winding method includes two-pole laying and spiral laying, which has good resistance to hydrogen embrittlement and fatigue. It is widely used in commercial vehicles such as hydrogen fuel cell trucks and buses. The high-pressure hydrogen storage cylinder of the hydrogen fuel cell vehicle includes a cylinder body with an inner liner and an outer shell, and a valve at the mouth of the cylinder body. The valve includes a valve body, a one-way valve located in the valve body, and a hydrogen supply flow. The valve has an internal passage, and the hydrogen filling nozzle includes an injection pipe that communicates with the internal passage and supplies high-pressure hydrogen flow, and a jet nozzle that communicates with the injection pipe, is formed at the front end of the injection pipe, and bends toward the inner liner of the bottle. The injection pipe extends axially into the bottle body, and the central longitudinal axis of the bottle body is the line connecting the centers of the two end faces of the bottle body. The centerline of the jet nozzle forms a preset angle with the central longitudinal axis. The preset angle is determined by computational fluid dynamics simulation optimization. By guiding the high-pressure hydrogen to diffuse uniformly along the inner wall of the bottle, the flow vortex and turbulence intensity are weakened, local gas compression heating is avoided, and the formation of local temperature hot spots on the surface of the inner liner is suppressed.

[0025] The bottle neck valve serves as the core connection between the bottle body and the external filling pipeline. Its valve body achieves a fixed seal with the bottle neck through a sealing structure. The one-way valve inside the valve adopts a valve core structure that can reciprocate along the central longitudinal axis, allowing only high-pressure hydrogen to flow into the bottle body in one direction. The channel inside the valve provides a flow path for the hydrogen. It should be understood that the double-layer structure of the hydrogen storage cylinder, the basic sealing and one-way flow function of the bottle neck valve, and the basic filling logic of the high-pressure hydrogen storage system are existing technologies and conventional techniques in the field, and are also common knowledge to those skilled in the art. The main improvement of this application is not the realization of the above-mentioned basic structure and function, but rather the optimization of the injection angle, installation position, gap size, and adaptation structure of the hydrogen filling nozzle to solve the turbulence and temperature hotspot problems of traditional nozzles, thereby improving filling performance and versatility.

[0026] Reference Figure 2 and Figure 4 The preset included angle ranges from 5° to 15°, as shown in the figure. It is stated that the value of the preset included angle is based on the 50L volume of the bottle, the eccentric distance is based on the inner diameter of the bottle being d=328mm, the length of the bottle being L=920mm, the length of the bottle being the axial length corresponding to the effective volume of the bottle, the inner liner wall thickness being 5mm, and the total wall thickness of the hydrogen storage bottle, that is, the overall thickness including the inner liner and the carbon fiber wound outer shell, being 24.8mm. The values ​​are based on the hydrogen refueling flow rate requirement of 120g / s.

[0027] The centerline of the injection pipe is offset radially from the central longitudinal axis, and the distance between the centerline of the injection pipe and the central longitudinal axis is the eccentric distance, which is optimized by fluid dynamics.

[0028] Reference Figure 2 The eccentricity distance is the perpendicular distance between the centerline of the injection pipe and the central longitudinal axis. The value of the eccentricity distance ranges from 1mm to 10mm, and is represented by h in the figure. The value of the eccentricity distance is based on the 50L volume of the bottle, the inner diameter of the bottle is d=328mm, the length of the bottle is L=920mm, and the value is based on the hydrogen filling flow rate requirement of 120g / s.

[0029] One end of the hydrogen filling nozzle's injection pipe is sealed and connected to the internal channel of the bottle valve, while the other end extends axially into the bottle body, with an extension length set at 35mm to ensure the nozzle is in the optimal injection position. The injection pipe is made entirely of pressure-resistant alloy material, suitable for high-pressure filling conditions of 875 bar, and can withstand the impact of high-pressure hydrogen with a flow rate exceeding Mach 1 during filling, preventing pipe deformation. Based on the flow characteristics of compressible fluids, high-pressure hydrogen with a flow rate exceeding Mach 1 is a typical compressible fluid, and its flow behavior is significantly affected by the Mach number. Traditional nozzles do not consider the turbulence generation mechanism of compressible fluids, resulting in the airflow directly impacting the rear of the bottle and causing vortices. One of the core improvements of this application is that the centerline of the injection pipe is offset radially perpendicular to the central longitudinal axis, forming an eccentric structure. This design, in conjunction with the optimized injection angle, changes the incident path of high-pressure hydrogen, preventing airflow convergence and the formation of strong turbulence. This design differs from the traditional center-aligned installation method of nozzles and is one of the key structures for turbulence suppression.

[0030] Reference Figure 5The jet nozzle and the injection pipe are integrally formed and bent towards the inner liner of the bottle. The bending angle is the preset included angle α, which is determined by CFD simulation optimization. Fluid dynamics principles show that the generation of turbulence is closely related to the flow direction and velocity gradient of the airflow. When the airflow is injected at a non-optimized angle, it is prone to violent interaction with the inner wall of the bottle or residual gas, resulting in an increase in turbulence intensity, while laminar flow can achieve uniform diffusion. Referring to Table 1, this embodiment verifies the optimization range of the angle through 10 sets of simulation experiments: Cases 1-4 are the optimization schemes of this embodiment, with the nozzle set vertically upward. When the preset included angle is 5°-15°, the maximum pressure when the hydrogen storage tank temperature rises to 85° is 545.8 bar (5°), 549 bar (10°), and 534 bar (15°), respectively. However, in Cases 5-7, when the included angle is 20°, 30°, and 60°, the maximum pressure is only 477 bar, 320 bar, and 162 bar, which is significantly lower than the optimized angle range. Compared with the traditional nozzles in the prior art, the maximum pressure of the Leclerc nozzle in Case 8 is only 138 bar, the Mercedes star nozzle in Case 9 is 216 bar, and the three-way nozzle in Case 10 is 135 bar. The maximum pressure corresponding to the optimized angle of this application is 2.5-4 times that of the traditional nozzle. This data comparison shows that a preset angle of 5°-15° can guide high-pressure hydrogen to diffuse uniformly in a laminar flow along the inner wall of the bottle, weakening the intensity of flow vortices and turbulence, avoiding local gas compression heating, and thus inhibiting the formation of hot spots on the surface of the inner liner.

[0031] One end of the injection pipe is provided with an external thread structure, and the end of the valve channel of the bottle mouth valve is provided with a matching internal thread structure. The injection pipe is detachably and fixedly assembled with the bottle mouth valve through a threaded connection. The hydrogen filling nozzle is a replaceable structure, and the hydrogen filling nozzle with a corresponding preset included angle and eccentric distance can be replaced according to the length and inner diameter of the bottle body.

[0032] The injection pipe is detachably and fixedly assembled with the internal thread structure of the valve's inner channel via an external thread structure. Since different specifications of hydrogen storage cylinders have different lengths and inner diameters, the optimal injection angle and eccentricity distance need to be adjusted accordingly. This application, through a replaceable structure, allows for direct replacement of nozzles with corresponding parameters without modifying the valve or cylinder body. For example, for a standard hydrogen storage cylinder with a 50L volume, an inner diameter d of 328mm, and a length L of 920mm, a nozzle with a 10° angle and a 5mm eccentricity distance can be selected. For other specifications of hydrogen storage cylinders, corresponding models within the 5°-15° angle range can be matched, solving the problem of poor versatility of traditional fixed nozzles.

[0033] Reference Figure 3The injection pipe has a connecting pipe inside, which is positioned opposite to the gas flow channel inside the one-way valve. An airflow gap is formed between the connecting pipe and the gas flow channel. This airflow gap has a longitudinal dimension of 2 mm, and this longitudinal dimension remains constant throughout the entire reciprocating movement of the one-way valve along its central longitudinal axis. (The figure uses...) The analysis indicates that, based on fluid dynamics, an excessively large gap can lead to airflow turbulence, while an excessively small gap can obstruct flow. A constant gap of 2mm ensures the cross-sectional area for high-pressure hydrogen flow, meeting the mass flow rate requirement of 120g / s, while also preventing eddy current disturbances at the gap. Simulation data shows that this gap design reduces hydrogen flow resistance by more than 15%, and, combined with the injection angle and eccentric design, further suppresses turbulence generation, ensuring stable airflow.

[0034] The nozzle has a circular cross-sectional shape and an inner diameter of 2mm to 8mm.

[0035] The preset included angle and eccentric distance were obtained through computational fluid dynamics simulation optimization, and the simulation boundary conditions met the requirements of a temperature range of 40°C to 85°C and a maximum injection pressure of 875 bar.

[0036] The cross-sectional shape of the nozzle can be circular, elliptical, or rhomboid, with an inner diameter of 2mm-8mm, matching the outlet size of the converging section to ensure smooth hydrogen ejection.

[0037] The optimization process of the preset included angle and eccentricity distance is implemented based on CFD simulation. The simulation boundary conditions strictly follow the SAE J2601 hydrogenation protocol, with a temperature range of -40℃ to 85℃ and a maximum filling pressure of 875 bar. The initial state is that hydrogen enters at a constant pressure of -40℃ and 85 bar, and the final cylinder temperature rises to 85℃. The simulation process combines key parameters such as Reynolds number, Mach number, and turbulence intensity to analyze the gas flow state under different structural parameters through numerical simulation. Comparison of simulation data shows that the optimized schemes of this application, Cases 1-4, achieve the best balance between process time and pressure stability: Case 3 has a process time of 12.46s and a maximum pressure of 549 bar, which ensures sufficient filling volume, avoids the inefficient filling of Case 8, and overcomes the problem of insufficient filling volume in Case 6, where the filling volume increases with higher pressure.

[0038] The core improvement of this embodiment lies in the 5°-15° preset included angle and radial eccentric structure determined through CFD simulation optimization, combined with a 2mm constant airflow gap and a replaceable adapter design, forming a synergistic technical solution. Through comparison of simulation data with existing technologies, the significant advantages of this application in turbulence suppression, temperature hotspot control, filling performance, and versatility are fully demonstrated. Its technical details and principle design differ from traditional nozzles, exhibiting outstanding creativity and practicality.

[0039] Lechler, a traditional manufacturer in the nozzle field, initially developed its nozzle products based on liquid atomization technology patents, later expanding to high-pressure fluid applications such as tank cleaning and gas purification and cooling. Lechler nozzles used in high-pressure hydrogen refueling employ a core structure with a single, straight-through injection channel. The centerline of the injection tube coincides with the longitudinal axis of the hydrogen storage tank, with no eccentric layout. The nozzle has a standard circular, straight-through structure, and some models incorporate a turbulence generator to enhance fluid diffusion. Its working principle involves high-pressure-driven hydrogen gas being injected directly into the tank along the central longitudinal axis, filling the tank through natural diffusion after exiting the nozzle. The rotating jet design concept used in tank cleaning is partially adopted in hydrogen refueling nozzles, attempting to expand the coverage area through jet rotation. However, this design has significant technical flaws: Firstly, the centrally directed airflow path causes high-speed hydrogen to directly impact the rear of the cylinder, resulting in strong turbulence after violent collisions with residual gas. The turbulence intensity TI ≥ 0.3, with a significant local gas compression and heating effect, easily forming temperature hotspots at the rear of the cylinder. Secondly, while the built-in turbulence generator can expand the diffusion range, it further exacerbates airflow turbulence, leading to excessive pressure loss during hydrogen filling. Simulation data from this application shows that, under the conditions of a 50L hydrogen storage cylinder and a filling flow rate of 120g / s, the maximum pressure of the Lechler nozzle when the cylinder temperature rises to 85℃ is only 138 bar, with a filling volume far lower than the actual usage requirements. Moreover, the process time is only 2.23s, reflecting the problem of uneven airflow diffusion and rapid pressure saturation caused by local impacts.

[0040] The Mercedes star-shaped nozzle's technological prototype originated from the high-pressure piezoelectric nozzle in its BlueEffect Propulsion system, and was later structurally modified for use in high-pressure gas jet applications. Its core structure is a combination of a central nozzle and circumferentially distributed star-shaped nozzles, typically consisting of 5-6 nozzles arranged radially in a star shape. The jet angle, with the nozzle centerline and the central longitudinal axis fixed at 30°-60°, employs a micron-level conical annular structure, designed to achieve uniform fluid filling through multi-directional jetting. Its working principle utilizes high-pressure piezoelectric control technology to achieve precise jetting; the airflow from multiple nozzles simultaneously converges and diffuses within the bottle, theoretically improving coverage uniformity. However, this design did not optimize for the compressible fluid characteristics of hydrogen and the structure of the hydrogen storage tank cavity: First, the star-shaped nozzle angle is too large, ranging from 30° to 60°, causing multiple airflows to converge and collide in the middle of the tank, forming strong airflow interference and failing to effectively suppress turbulence intensity; second, although the conical annular nozzle design is suitable for fuel stratified injection, hydrogen molecules have smaller mass and faster flow velocity, and this structure easily causes vortices to be generated at the nozzle, further aggravating pressure loss; third, the fixed nozzle angle cannot be adapted to different specifications of hydrogen storage tanks, resulting in poor versatility. Simulation data shows that the maximum filling pressure of the Mercedes star-shaped nozzle under the same operating conditions is 216 bar, which is higher than that of the Lechler nozzle, but still only 39.3% of the optimized scheme in this application. Although the temperature hotspot areas are more dispersed than those of the Lechler nozzle, there are still 3-4 local high-temperature points, which cannot meet the safety requirements of high-pressure hydrogen storage.

[0041] The three-way nozzle is a standard design in high-pressure fluid injection. Its core structure consists of three nozzles evenly distributed at 120° angles at the end of the injection pipe. The angle between the nozzle centerline and the central longitudinal axis is fixed at 45°-90°, and the inner diameter of the three nozzles is identical. The injection pipe is installed with center alignment and no eccentricity. Its working principle is to divide high-pressure hydrogen into three streams through three-way flow splitting, injecting them into the cylinder from different directions. This attempts to reduce localized airflow concentration through multi-directional coverage. This design concept has been applied in some low-pressure fluid filling scenarios, but it was not specifically optimized for high-pressure hydrogen refueling. Its technical defects are mainly reflected in the following aspects: First, the injection angles of the three nozzles are not designed in accordance with the inner wall contour of the hydrogen storage tank. The large angles of 45°-90° cause the airflow to be mainly concentrated in the upper and middle parts of the tank, while the lower area fills slowly, forming a significant concentration gradient and indirectly aggravating local compression heating. Second, without an eccentric layout, the convergence area of ​​the three airflows is still concentrated near the central longitudinal axis, and turbulence remains prominent. Furthermore, the limited number of nozzles leads to uneven coverage. Third, the fixed angles and layout cannot be adapted to hydrogen storage tanks of different lengths and inner diameters, resulting in poor adaptability. Simulation data shows that the maximum filling pressure of the three-way nozzle under the same operating conditions is only 135 bar, which is close to that of the Lechler nozzle. The temperature hotspots are concentrated in the convergence area of ​​the three airflows and the insufficiently covered area at the bottom of the tank. The filling performance and safety cannot meet the requirements of high-pressure hydrogen storage.

[0042] The common problem with the above three existing nozzle technologies is that they do not systematically optimize core parameters such as injection angle, installation position, and gap size based on the compressible fluid characteristics of high-pressure hydrogen and the structure of the hydrogen storage tank cavity. Instead, they attempt to solve the filling uniformity problem by improving a single structure, such as multiple nozzles, rotating jets, or three-way splitting, resulting in poor turbulence suppression, high risk of temperature hotspot formation, and insufficient filling volume.

[0043] This embodiment does not negate the basic design logic of high-pressure driven injection and multi-directional diffusion in existing technologies. These are existing technologies and common technical means in the field, and are common knowledge to those skilled in the art. Rather, it addresses the unresolved issue of compressible fluid turbulence generation in existing technologies by using CFD simulation to optimize and determine key parameters such as the optimal injection angle of 5°-15°, radial eccentric layout, and 2mm constant airflow gap, forming a synergistic technical solution. Ultimately, it achieves the technical effect of reducing turbulence intensity by more than 40% and increasing filling pressure by 2.5-4 times. This is the core difference between this embodiment and existing technologies.

[0044] Table 1. Simulation of preset included angles under industry standard constraints of hydrogen fuel refueling systems Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0045] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from the scope of the invention. The spirit and scope of the invention are as follows: Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A hydrogen refueling nozzle for use as a valve at the mouth of a high-pressure hydrogen storage cylinder in a hydrogen fuel cell vehicle, the high-pressure hydrogen storage cylinder comprising a cylinder body having an inner liner and an outer shell, and a valve at the mouth of the cylinder body, the valve comprising a valve body, a one-way valve disposed within the valve body, and an internal valve passage for hydrogen flow, characterized in that, The hydrogen filling nozzle includes an injection pipe that communicates with the valve channel and supplies high-pressure hydrogen flow, and a jet nozzle that communicates with the injection pipe, is formed at the front end of the injection pipe, and bends toward the inner liner of the bottle. The line connecting the centers of the two end faces of the bottle is the central longitudinal axis. The centerline of the jet nozzle forms a preset angle of 5°-15° with the central longitudinal axis. By guiding the high-pressure hydrogen to diffuse along the inner wall of the inner liner of the bottle, the flow vortex and turbulence intensity are weakened.

2. The hydrogen refueling nozzle according to claim 1, characterized in that, The centerline of the injection pipe is offset radially from the central longitudinal axis.

3. The hydrogen refueling nozzle according to claim 2, characterized in that, The distance between the centerline of the injection pipe and the central longitudinal axis is the eccentric distance, which ranges from 1 mm to 10 mm.

4. The hydrogen refueling nozzle according to claim 1, characterized in that, One end of the injection pipe is provided with an external thread structure, and the end of the valve channel of the bottle mouth valve is provided with a matching internal thread structure. The injection pipe is detachably and fixedly assembled with the bottle mouth valve through a threaded connection. The hydrogen filling nozzle is a replaceable structure, and the hydrogen filling nozzle with a corresponding preset included angle and eccentric distance can be replaced according to the length and inner diameter of the bottle body.

5. The hydrogen refueling nozzle according to claim 1, characterized in that, The injection pipe is provided with a connecting pipe, which is arranged opposite to the gas flow channel in the one-way valve. An airflow gap is formed between the connecting pipe and the gas flow channel, and the airflow gap has a longitudinal dimension.

6. The hydrogen refueling nozzle according to claim 5, characterized in that, The longitudinal dimension is 2 mm, and the longitudinal dimension remains constant throughout the entire process of the one-way valve reciprocating along the central longitudinal axis.

7. The hydrogen refueling nozzle according to claim 1, characterized in that, The nozzle has a circular cross-sectional shape and an inner diameter of 2mm to 8mm.

Images