Method for arranging baffle plate of high-pressure hydrogen storage tank based on jet flow dissipation transition point and hydrogen storage tank

Abstract

This invention provides a method for arranging baffles in a high-pressure hydrogen storage tank based on the jet dissipation transition point, and a hydrogen storage tank in the field of hydrogen storage. The method includes: establishing a baseline flow field of the high-pressure hydrogen storage tank under conditions where no baffles are installed; obtaining the axial velocity distribution and turbulent kinetic energy distribution along the central axis of the high-pressure hydrogen storage tank in the baseline flow field; identifying the location where the turbulent kinetic energy of the fluid first reaches its peak value in the region where the ratio of axial velocity to fluid inlet velocity first decays below a preset ratio threshold, and determining this spatial location as the jet dissipation transition point; arranging baffles at the jet dissipation transition point, or arranging baffles within a preset axial range near the jet dissipation transition point. This method can determine a more optimal baffle position. By arranging the baffles at the jet dissipation transition point, the residual axial kinetic energy of the jet is efficiently converted into radial turbulent kinetic energy, inducing large-scale vortex structures, thereby significantly enhancing downstream wall heat transfer.

Description

Technical Field

[0001] This invention relates to the field of hydrogen storage technology, and in particular to a method for arranging baffles in a high-pressure hydrogen storage tank based on the jet dissipation transition point, and a hydrogen storage tank. Background Technology

[0002] During rapid filling of high-pressure hydrogen storage tanks (35MPa / 70MPa), the temperature inside the tank rises sharply due to the Joule-Thomson effect and compression effect, which may exceed the 85℃ limit stipulated by international standards, causing safety hazards such as aging of the inner liner and structural failure.

[0003] Existing thermal management technologies are mainly divided into two categories. The first category is active methods: hydrogen pre-cooling and optimized filling curves (multi-stage pressurization, variable-rate filling, etc.), but these methods are energy-intensive, involve complex equipment, and are costly. The second category is passive methods: enhancing heat exchange through internal structural optimization, such as setting up baffles, deflectors, and guide vanes. These methods are low-cost, require no additional energy consumption, and represent a more promising direction. Among existing technologies, CN115164088A, a hydrogen storage system and its method for optimizing pressure and temperature control during rapid hydrogen filling, uses a programmable controller and flow meter to optimize and control the pressure and temperature during the hydrogen filling process. This is an external control strategy and does not involve internal structural optimization. CN116906820A, a high-pressure hydrogen filling system and method for near-isothermal rapid filling, absorbs the heat generated during the hydrogen filling process by uniformly distributing phase change heat storage material inside the hydrogen storage tank.

[0004] Some existing technologies propose installing baffles inside the tank to enhance heat exchange.

[0005] The applicant has discovered that the existing technology has at least the following technical problems: the placement of the baffle lacks theoretical basis and is mostly determined by trial and error based on experience, which leads to unstable effects and may even trigger a "thermal lock-in effect" in the wrong position (such as the downstream dissipation zone), which may exacerbate the thermal risk. Summary of the Invention

[0006] The purpose of this invention is to provide a method for arranging baffles in a high-pressure hydrogen storage tank based on the jet dissipation transition point, and a hydrogen storage tank in general. This addresses the technical problems in existing technologies where the placement of baffles for heat exchange within hydrogen storage tanks lacks theoretical basis, leading to unstable performance and potentially exacerbating thermal risks due to incorrect placement. The numerous technical effects of the preferred solutions among the various technical solutions provided by this invention are detailed below.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] The present invention provides a method for arranging baffles in a high-pressure hydrogen storage tank based on the jet dissipation transition point, the method comprising: Establish the baseline flow field of the high-pressure hydrogen storage tank under the condition of no baffle; Obtain the axial velocity distribution and turbulent kinetic energy distribution along the central axis of the high-pressure hydrogen storage tank in the baseline flow field; Within the region where the ratio of axial velocity to fluid inlet velocity first decays to below a preset ratio threshold, the location where the turbulent kinetic energy of the fluid first reaches its peak is identified, and this spatial location is determined as the jet dissipation transition point. The baffle is arranged at the jet dissipation transition point, or the baffle is arranged within a preset axial range near the jet dissipation transition point.

[0009] Preferably, the method further includes: verifying the arrangement effect of the baffle based on the temperature field and / or flow field distribution after the baffle is set; Verifying the effectiveness of the baffle arrangement includes verifying one or more of the following: peak temperature, temperature uniformity, and flow resistance in the flow field with baffles.

[0010] Preferably, the baffle includes a first baffle, which is used when the length-to-diameter ratio of the hydrogen storage tank is greater than a preset value, and the first baffle cannot meet the downstream thermal management requirements: In the flow field after the first baffle has been set, the jet dissipation transition point identification step is repeated in the downstream region of the first baffle to identify the second jet dissipation transition point. A second baffle is set at or near the second jet dissipation transition point within a preset axial range, and the second baffle is set coaxially with the first baffle.

[0011] Preferably, the baffle is positioned away from the area where the jet is completely dissipated, in order to reduce the risk of localized heat accumulation or thermal lock-in caused by the baffle being positioned too far away.

[0012] Preferably, establishing the baseline flow field of the high-pressure hydrogen storage tank under conditions without baffles includes: A two-dimensional axisymmetric CFD simulation model of the high-pressure hydrogen storage tank was established. Set boundary conditions, which include initial pressure, initial temperature, mass flow rate, and ambient heat transfer coefficient; Perform mesh independence verification and the effectiveness verification of the simulation model.

[0013] Preferably, obtaining the axial velocity distribution and turbulent kinetic energy distribution along the central axis of the high-pressure hydrogen storage tank in the baseline flow field includes: solving the CFD simulation model and normalizing the axial position of the high-pressure hydrogen storage tank; Extract the normalized data along the central axis of the high-pressure hydrogen storage tank, the data including: The axial velocity U c With the inlet velocity U of the fluid inlet Ratio U c / Uinlet Distribution data along the central axis of the high-pressure hydrogen storage tank; Data on the distribution of turbulent kinetic energy along the central axis of the high-pressure hydrogen storage tank; The process of normalizing the axial position of the high-pressure hydrogen storage tank includes: dividing the axial length of the high-pressure hydrogen storage tank into a range of [0,1] along the fluid flow direction, and marking the axial position of the high-pressure hydrogen storage tank accordingly.

[0014] Preferably, the baffle is coaxially arranged with the high-pressure hydrogen storage tank, and the baffle is symmetrically arranged about the central axis of the high-pressure hydrogen storage tank. The baffle is an annular baffle, and / or the baffle is provided with uniformly distributed perforations.

[0015] Preferably, the preset ratio threshold is 0.85-0.95; The opening ratio of the baffle is 40%-60%.

[0016] Preferably, the baffle is inclined, and the distance between the baffle and the central axis of the high-pressure hydrogen storage tank gradually decreases along the fluid flow direction. The inclination angle α between the baffle and the radial plane of the high-pressure hydrogen storage tank ranges from 15° to 30°.

[0017] The present invention also provides a hydrogen storage tank, including a tank body and at least one baffle disposed inside the tank body, wherein the position of the baffle is arranged according to the above-described high-pressure hydrogen storage tank baffle arrangement method based on the jet dissipation transition point.

[0018] The high-pressure hydrogen storage tank baffle arrangement method and hydrogen storage tank based on the jet dissipation transition point provided by this invention have the following advantages compared with the prior art: The jet dissipation transition point, as the critical point where the jet transitions from momentum-dominated to turbulence-dominated, has stronger shear layer instability. Placing the baffle at this point can maximize the utilization of the jet's residual axial kinetic energy, efficiently converting it into radial turbulent kinetic energy, inducing large-scale vortex structures, thereby significantly enhancing downstream wall heat transfer. The above method can determine a more optimal baffle position, achieving global synergy in temperature drop, temperature uniformity, and flow resistance, while revealing and avoiding the risk of thermal lock-in effect, providing a universal thermal management solution for storage tanks with different aspect ratios. Attached Figure Description

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

[0020] Figure 1This is a schematic diagram of the structure of the hydrogen storage tank of the present invention; Figure 2 It is the axial velocity distribution and turbulent kinetic energy distribution along the central axis of the high-pressure hydrogen storage tank in the baseline flow field under the condition of no baffle; Figure 3 This is a schematic diagram comparing the streamlines at the three baffle positions.

[0021] Figure 4 This is a schematic diagram comparing the temperature fields at the three baffle locations; Figure 5 This is a bar chart comparing the ISE indicators.

[0022] In the diagram: 1. Hydrogen storage tank; 2. Baffle. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] In the description of this invention, it should be understood that the terms "center," "length," "width," "height," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and "side," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0025] During rapid hydrogen refueling, the internal temperature of existing high-pressure hydrogen storage tanks can rise sharply due to the Joule-Thomson effect and compression, potentially exceeding the safety limits stipulated by international standards. This can lead to safety hazards such as aging of the inner liner and structural failure. Although existing technologies propose passive thermal management solutions that enhance heat exchange by installing baffles inside the tank, the placement of these baffles often lacks scientific theoretical basis and relies heavily on trial and error, resulting in unstable thermal management effects. In fact, improper placement may even trigger thermal lock-in effects, exacerbating thermal risks.

[0026] To address the aforementioned issues, this invention provides a method for arranging baffles in high-pressure hydrogen storage tanks based on the jet dissipation transition point. This method can determine a more optimal baffle position, achieving a global synergy in temperature drop, temperature uniformity, and flow resistance. Simultaneously, it reveals and mitigates the risk of thermal lock-in effect, providing a universal thermal management solution for storage tanks with different aspect ratios.

[0027] The following is combined Figures 1-5 The technical solution provided by this invention will be described in more detail below.

[0028] Example 1 See Figures 1-5 As shown, the present invention provides a method for arranging baffles 2 in a high-pressure hydrogen storage tank 1 based on the jet dissipation transition point. This method includes: establishing a baseline flow field for the high-pressure hydrogen storage tank 1 under conditions where baffles 2 are not installed; see also... Figure 2 The axial velocity distribution and turbulent kinetic energy distribution along the central axis of the high-pressure hydrogen storage tank 1 in the baseline flow field are obtained; in the region where the ratio of axial velocity to fluid inlet velocity first decays to below a preset ratio threshold, the position where the turbulent kinetic energy of the fluid first reaches its peak is identified, and this spatial position is determined as the jet dissipation transition point; the baffle 2 is arranged at the jet dissipation transition point, or the baffle 2 is arranged within a preset axial range near the jet dissipation transition point.

[0029] The baseline flow field described above under the condition of not installing baffle 2 refers to the flow state formed by the fluid during the filling process when baffle 2 is not installed inside the high-pressure hydrogen storage tank 1. This flow field is usually obtained through numerical simulation or experimental measurement.

[0030] Turbulent kinetic energy distribution refers to the variation in turbulence intensity along the central axis of the high-pressure hydrogen storage tank 1. Turbulent kinetic energy is a physical quantity that measures the intensity of fluid turbulence fluctuations, and its peak value usually indicates regions where fluid mixing and energy dissipation are more intense.

[0031] See Figure 1 As shown, baffle 2 is a structural component installed inside the high-pressure hydrogen storage tank 1. Its main function is to change the fluid flow path, enhance fluid mixing, thereby promoting heat transfer inside the tank and improving temperature uniformity.

[0032] This embodiment analyzes the evolution of the jet within the tank without baffle 2, revealing the intrinsic relationship between the jet dissipation transition point (JDT point) and superior thermal management. The core principle is that the jet sequentially passes through a "potential core region," a "transition region," and a "complete dissipation region" from the inlet to the tank bottom. Within the transition region, there exists a critical point where momentum-dominated flow transitions to turbulence-dominated flow—the jet dissipation transition point (JDT point). At this point, the shear layer is most unstable. Placing baffle 2 here maximizes the utilization of the jet's residual axial kinetic energy, efficiently converting it into radial turbulent kinetic energy, inducing large-scale vortex structures, thereby enhancing downstream wall heat transfer and eliminating hot spots.

[0033] The baffle can also be placed within a preset axial range before or after the jet dissipation transition point, for example, within 5 to 10 millimeters upstream or downstream of the jet dissipation transition point, to adapt to the flexibility of actual engineering installation, while still effectively utilizing the flow field characteristics of this key area.

[0034] As an optional implementation, the method further includes: verifying the arrangement effect of the baffle 2 based on the temperature field and / or flow field distribution after the baffle 2 is set; verifying the arrangement effect of the baffle 2 includes: verifying one or more of the peak temperature, temperature uniformity and flow resistance in the flow field with the baffle 2.

[0035] Verification based on the temperature and / or flow field distribution after the installation of baffle 2 refers to the process of re-observing the temperature distribution and fluid flow characteristics inside the hydrogen storage tank 1 through numerical simulation (e.g., using a computational fluid dynamics (CFD) simulation model) or experimental testing after the baffle 2 is initially arranged as described above. The temperature field reflects the temperature values ​​at various points inside the hydrogen storage tank 1, while the flow field distribution describes the dynamic characteristics of the fluid, such as velocity and pressure. By analyzing these field distributions, the influence of baffle 2 on heat transfer and fluid motion inside the hydrogen storage tank 1 can be intuitively understood.

[0036] Verifying the effectiveness of the baffle 2 arrangement allows for an assessment of its specific improvement to the internal environment of the hydrogen storage tank 1. For example, verifying the peak temperature aims to ensure that the baffle 2 effectively reduces or eliminates potential localized overheating areas within the tank, preventing safety hazards or material performance degradation caused by excessively high temperatures. Verifying temperature uniformity ensures a balanced temperature distribution within the tank; good temperature uniformity helps reduce thermal stress and improves the utilization efficiency of the hydrogen storage material and the stability of the charging and discharging process. Verifying flow resistance assesses the degree to which the baffle 2 impedes fluid flow, ensuring that optimized thermal management does not significantly increase energy consumption or reduce efficiency during the charging and discharging process. These verification indicators can be evaluated individually or in combination according to actual needs.

[0037] By verifying key indicators such as peak temperature, temperature uniformity, and flow resistance in the flow field with baffle 2, it is ensured that the arranged baffle 2 can not only effectively guide the fluid and promote jet dissipation, but also avoid local overheating, uneven temperature distribution, or excessive flow resistance caused by improper baffle 2 placement. This makes the arrangement of baffle 2 more reliable and optimized, thereby significantly improving the overall thermal management performance and operational safety of the high-pressure hydrogen storage tank 1.

[0038] For certain specific operating conditions, such as when the hydrogen storage tank 1 has a large length-to-diameter ratio, setting only one baffle 2 may not be sufficient to completely control the fluid flow and heat distribution inside the entire tank, especially in the downstream area far from the inlet, where there may still be problems of local overheating or uneven temperature.

[0039] To address the above problems, as an optional implementation method, see [link to alternative implementation]. Figures 1-5 As shown, the baffle 2 in this embodiment includes a first baffle 2. When the length-to-diameter ratio of the hydrogen storage tank 1 is greater than a preset value, and the first baffle 2 cannot meet the downstream thermal management requirements: in the flow field after the first baffle 2 has been set, the jet dissipation transition point identification step is repeatedly performed in the downstream region of the first baffle 2 to identify a second jet dissipation transition point. A second baffle 2 is set at or near the second jet dissipation transition point within a preset axial range. The second baffle 2 is coaxially arranged with the first baffle 2. The material of the baffle 2 is the same as or has the same or similar coefficient of thermal expansion as the inner liner material of the hydrogen storage tank 1.

[0040] Specifically, for ultra-long storage tanks with L / D > 8, multiple baffles 2 can be arranged based on multi-level JDT points. Here, L / D represents the length-to-diameter ratio of the hydrogen storage tank 1. L / D > 8 means that the length-to-diameter ratio of the hydrogen storage tank 1 is greater than 8, that is, the axial length L of the hydrogen storage tank 1 is greater than 8 times its diameter D.

[0041] See Figures 1-4 When the length-to-diameter ratio of the hydrogen storage tank 1 is too large or a single baffle 2 cannot meet the downstream thermal management requirements, this application can effectively solve the problems of local overheating and temperature non-uniformity in the downstream region. Specifically, the jet dissipation transition point is repeatedly identified in the downstream region of the first baffle 2, and a second baffle 2 is set, so that after the initial regulation of the fluid by the first baffle 2, the secondary jet in the downstream region can also be further intervened. The setting of the second baffle 2 can further disperse and homogenize the fluid in the downstream region, promote sufficient heat exchange between the fluid and the tank wall, effectively suppress the formation of local hot spots, and improve the temperature uniformity inside the entire hydrogen storage tank 1. Of course, the above steps can be repeated to set a third baffle 2, a fourth baffle 2, etc.

[0042] The above method is particularly suitable for hydrogen storage tank 1 with a large length-to-diameter ratio, and can significantly improve its overall thermal management performance, ensuring the efficiency and safety of the hydrogen charging and discharging process.

[0043] As an alternative implementation, see [link to implementation details]. Figure 2 As shown, the baffle 2 is positioned to avoid the area where the jet is completely dissipated, thereby reducing the risk of localized heat accumulation or thermal lock-in caused by the position of the baffle 2.

[0044] The region of complete jet dissipation refers to the area where, after the high-pressure fluid jet enters hydrogen storage tank 1, its momentum and turbulent characteristics have significantly decreased, the fluid velocity tends to level off, and turbulent mixing is no longer significant. In this region, the axial velocity of the fluid has decreased significantly, and the turbulent kinetic energy has also decreased to a low level, indicating that the jet's energy has been largely converted into heat energy and diffused.

[0045] In this embodiment, when determining the placement of the baffle 2, not only was the jet dissipation transition point considered to optimize the initial flow field, but by ensuring that the baffle 2 avoids the region of complete jet dissipation, the problems of fluid stagnation and heat accumulation that may occur due to the baffle 2 being positioned too far back are effectively avoided. This allows the baffle 2 to remain in an effective flow environment, promoting uniform heat exchange inside the hydrogen storage tank 1 and significantly reducing the risk of local overheating and thermal lock-in.

[0046] As an alternative implementation, see [link to implementation details]. Figures 2-5 As shown, the baseline flow field of high-pressure hydrogen storage tank 1 under the condition of no baffle 2 is established, including: establishing a two-dimensional axisymmetric CFD simulation model of high-pressure hydrogen storage tank 1; setting boundary conditions, including initial pressure, initial temperature, mass flow rate, and ambient heat transfer coefficient; and performing mesh independence verification and simulation model effectiveness verification.

[0047] Computational fluid dynamics (CFD) simulation models are currently the most advanced tools for solving fluid motion equations numerically, capable of simulating fluid flow and heat transfer behavior in complex geometries. For rotationally symmetric structures like the high-pressure hydrogen storage tank 1, establishing a two-dimensional axisymmetric CFD simulation model can significantly simplify computational complexity and improve computational efficiency while maintaining accuracy. This model can accurately capture the flow and temperature field distributions inside the hydrogen storage tank 1 during the hydrogen filling process.

[0048] By employing the above technical solution, when establishing the baseline flow field of the high-pressure hydrogen storage tank 1 under the condition of not having baffle 2, a two-dimensional axisymmetric CFD simulation model is used. Combined with boundary condition settings, mesh independence verification, and simulation model validity verification, the obtained baseline flow field data can be ensured to have high accuracy and reliability. This avoids the identification deviation of the jet dissipation transition point caused by inaccurate flow field data, thus facilitating the precise placement of baffle 2.

[0049] As an alternative implementation, see [link to implementation details]. Figures 2-5As shown, in this embodiment, the axial velocity distribution and turbulent kinetic energy distribution along the central axis of the high-pressure hydrogen storage tank 1 in the baseline flow field are obtained, including: solving the CFD simulation model and normalizing the axial position of the high-pressure hydrogen storage tank 1; extracting the data on the central axis of the high-pressure hydrogen storage tank 1 after normalization, the data including: the ratio U of axial velocity to fluid inlet velocity. c / U inlet Distribution data along the central axis of high-pressure hydrogen storage tank 1; distribution data of turbulent kinetic energy along the central axis of high-pressure hydrogen storage tank 1; wherein, the axial position of high-pressure hydrogen storage tank 1 is normalized, including: dividing the axial length of high-pressure hydrogen storage tank 1 into the range of [0,1] along the fluid flow direction, and marking the axial position of high-pressure hydrogen storage tank 1 accordingly.

[0050] See Figure 2 The axial position of the high-pressure hydrogen storage tank 1 is normalized by mapping its actual axial length to a dimensionless interval [0,1]. For example, the fluid inlet can be marked as 0, the end of the fluid flow direction can be marked as 1, and any intermediate axial position is marked according to its proportion in the total length. This normalization method allows the flow field data of high-pressure hydrogen storage tanks 1 of different sizes or under different operating conditions to be compared and analyzed in a unified coordinate system.

[0051] After solving the CFD simulation model, axial position normalization is applied to ensure that the flow field data obtained from different high-pressure hydrogen storage tanks or under different operating conditions have a unified reference standard, which greatly improves the standardization and comparability of data analysis.

[0052] See Figure 3 , Figure 4 As shown, taking hydrogen storage tank 1 with L / D=4.5 as an example, placing baffle 2 at the jet dissipation transition point (JDT point) (Z / L=0.4) can increase the downstream wall heat flux by more than 70%, reduce the peak temperature from 431K to 342K (below the safety limit of 358K), and reduce the axial temperature difference by 72%, which is significantly better than other positions.

[0053] Where Z / L is the normalized coordinate of the axial position inside the high-pressure hydrogen storage tank 1, and its specific meaning is as follows: Z represents the actual distance from the inlet (filling port) of the hydrogen storage tank 1 along the axial direction to a certain point; L represents the total effective axial length of the hydrogen storage tank 1 (from the inlet to the bottom of the tank); Z / L = 0.4 means that the point is located at 40% of the axial length of the hydrogen storage tank 1, that is, 0.4 times the tank length from the inlet.

[0054] As an alternative implementation, see [link to implementation details]. Figure 1The baffle 2 is coaxially arranged with the high-pressure hydrogen storage tank 1, and the baffle 2 is symmetrically arranged about the central axis of the high-pressure hydrogen storage tank 1. The baffle 2 is an annular baffle 2, and / or, the baffle 2 is provided with uniformly distributed perforations.

[0055] The annular baffle 2 is a disc-shaped structure with a central through-hole. It allows a portion of the fluid to pass directly through the central region, providing some fluid resistance and turbulence generation while avoiding complete blockage of the central flow path. Through its inner and outer edges, the annular baffle 2 interacts with the fluid, effectively altering the flow direction and velocity distribution, promoting fluid mixing, and thus enhancing heat transfer efficiency. The baffle 2 can be provided with uniformly distributed perforations, allowing some fluid to pass through it in small jets.

[0056] By arranging the baffle 2 coaxially with the high-pressure hydrogen storage tank 1 and symmetrically about its central axis, local velocity unevenness or flow deviation can be avoided when the fluid passes through the baffle 2. The combination of the above structure and the jet dissipation transition point arrangement method can regulate the flow field and temperature field inside the high-pressure hydrogen storage tank 1, effectively reducing the peak temperature during hydrogen charging and discharging, improving temperature uniformity, and controlling the flow resistance within an acceptable range.

[0057] As an alternative implementation, see [link to implementation details]. Figure 1 The preset ratio threshold is 0.85-0.95, preferably 0.9; the opening ratio of baffle 2 is 40%-60%, balancing the turbulence effect and resistance loss.

[0058] After the fluid is injected at high speed into the high-pressure hydrogen storage tank 1 from the inlet, its axial velocity will gradually decrease. When the axial velocity U c With the inlet velocity U of the fluid inlet Ratio U c / Uinlet When the jet first decays below the preset proportional threshold, it indicates that the jet has begun to diffuse and dissipate significantly, entering the transition region. Setting this threshold in the range of 0.85-0.9 ensures accurate capture of the spatial location where the fluid turbulent kinetic energy reaches its peak during the stage when the jet has not yet fully dissipated but has begun to decelerate significantly, thus more precisely locating the jet dissipation transition point. This range is selected based on extensive simulation and experimental data analysis of the jet characteristics within the high-pressure hydrogen storage tank 1, avoiding premature identification due to an excessively high threshold (the jet has not yet fully developed) or premature identification due to an excessively low threshold (the jet has already excessively dissipated).

[0059] As an alternative implementation, see [link to implementation details]. Figure 1As shown, the baffle 2 is inclined, and the distance between the baffle 2 and the central axis of the high-pressure hydrogen storage tank 1 gradually decreases along the fluid flow direction. The inclination angle α between the baffle 2 and the radial plane of the high-pressure hydrogen storage tank 1 ranges from 15° to 30°, guiding the airflow to scour the wall. This structure can effectively utilize the high turbulent kinetic energy at the JDT point, efficiently converting the residual axial kinetic energy of the jet into radial motion, significantly improving the wall heat transfer efficiency.

[0060] Specifically, the method of the present invention includes the following steps: Step 1: Establish a baseline model without baffles 2; establish a two-dimensional axisymmetric CFD simulation model of the hydrogen storage tank 1 to be optimized; set boundary conditions: initial pressure, initial temperature, mass flow rate, environmental heat transfer coefficient, etc.; perform mesh independence verification and model validity verification.

[0061] Step 2: Obtain jet evolution characteristic parameters; solve the CFD model and extract data along the centerline of the storage tank: normalize the axial position of the high-pressure hydrogen storage tank 1, and the axial velocity U c With the inlet velocity U of the fluid inlet Ratio U c / Uinlet Distribution along the axial direction; distribution of turbulent kinetic energy along the axial direction.

[0062] Step 3: Identify the jet dissipation transition point (JDT point); determine the endpoint Z of the potential core region. pc The ratio of axial velocity to fluid inlet velocity first drops to 0.9; at Z≥Z pc Within the region, the point where the turbulent kinetic energy first reaches its peak value is identified as the JDT point. Where Z... pc Z represents the axial position of the endpoint of the potential core region. dt The point represents the axial position at the starting point of the fully dissipated region.

[0063] Step 4: Arrange baffle 2 near JDT point; place the annular perforated baffle 2 at JDT point (or within the range of JDT point ± DT perforated baffle 2, where L represents the total effective axial length of hydrogen storage tank 1). Step 5: Verification and Evaluation; Perform CFD simulation on the scheme after arranging baffle 2 to obtain data such as temperature field, flow field, and wall heat flux; for example Figure 5 As shown, the Integrated Synergy Efficiency (ISE) index is calculated and compared with other candidate positions (such as before and after the JDT point) to verify the optimal completeness of the JDT point.

[0064] Step 6: Multi-stage expansion (for ultra-long storage tanks with L / D>8); If the first baffle 2 cannot eliminate the downstream hot spot, repeat steps 2-4 for the downstream flow field, identify the second JDT point, arrange the second baffle 2, and so on.

[0065] Example 2 This embodiment provides a hydrogen storage tank 1, see [link / reference] Figure 1 It includes a tank body and at least one baffle 2 disposed inside the tank body, the position of the baffle 2 being arranged according to the above-described baffle 2 arrangement method of high-pressure hydrogen storage tank 1 based on jet dissipation transition point.

[0066] Through the above technical solution, the hydrogen storage tank 1, by precisely setting at least one baffle 2 inside the tank body, can effectively cut off or disperse the high-speed jet, thereby significantly reducing areas of excessively high local flow velocity and concentrated turbulent kinetic energy, and avoiding severe friction between hydrogen and the tank wall and local heat accumulation during the filling process. The precise position of the baffle 2 ensures that it promotes the mixing of fluids inside the tank and uniform heat distribution to the greatest extent without significantly increasing flow resistance, effectively suppressing the occurrence of peak temperature and improving the overall temperature uniformity. This structural implementation allows the hydrogen storage tank 1 to achieve a faster filling speed in actual filling operations, while ensuring higher safety and a longer service life, thereby improving the overall performance of the high-pressure hydrogen storage tank 1.

[0067] The specific features, structures, or characteristics described in this specification may be combined in any suitable manner in one or more embodiments or examples.

[0068] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0069] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for arranging baffles in a high-pressure hydrogen storage tank based on the jet dissipation transition point, characterized in that, The method includes: Establish the baseline flow field of the high-pressure hydrogen storage tank under the condition of no baffle; Obtain the axial velocity distribution and turbulent kinetic energy distribution along the central axis of the high-pressure hydrogen storage tank in the baseline flow field; Within the region where the ratio of axial velocity to fluid inlet velocity first decays to below a preset ratio threshold, the location where the turbulent kinetic energy of the fluid first reaches its peak is identified, and this spatial location is determined as the jet dissipation transition point. The baffle is arranged at the jet dissipation transition point, or the baffle is arranged within a preset axial range near the jet dissipation transition point.

2. The high-pressure hydrogen storage tank baffle arrangement method based on the jet dissipation transition point according to claim 1, characterized in that, The method further includes: verifying the arrangement effect of the baffle based on the temperature field and / or flow field distribution after the baffle is set; Verifying the effectiveness of the baffle arrangement includes verifying one or more of the following: peak temperature, temperature uniformity, and flow resistance in the flow field with baffles.

3. The high-pressure hydrogen storage tank baffle arrangement method based on the jet dissipation transition point according to claim 1, characterized in that, The baffle includes a first baffle. When the length-to-diameter ratio of the hydrogen storage tank is greater than a preset value, and the first baffle cannot meet the downstream thermal management requirements: In the flow field after the first baffle has been set, the jet dissipation transition point identification step is repeated in the downstream region of the first baffle to identify the second jet dissipation transition point. A second baffle is set at or near the second jet dissipation transition point within a preset axial range, and the second baffle is set coaxially with the first baffle.

4. The high-pressure hydrogen storage tank baffle arrangement method based on the jet dissipation transition point according to claim 1, characterized in that, The baffle is positioned to avoid the area where the jet is completely dissipated, thereby reducing the risk of localized heat accumulation or thermal lock-in caused by the baffle being positioned too far away.

5. The high-pressure hydrogen storage tank baffle arrangement method based on the jet dissipation transition point according to claim 1, characterized in that, Establishing the baseline flow field of the high-pressure hydrogen storage tank under conditions without baffles includes: A two-dimensional axisymmetric CFD simulation model of the high-pressure hydrogen storage tank was established. Set boundary conditions, which include initial pressure, initial temperature, mass flow rate, and ambient heat transfer coefficient; Perform mesh independence verification and the effectiveness verification of the simulation model.

6. The high-pressure hydrogen storage tank baffle arrangement method based on the jet dissipation transition point according to claim 5, characterized in that, The acquisition of the axial velocity distribution and turbulent kinetic energy distribution along the central axis of the high-pressure hydrogen storage tank in the baseline flow field includes: solving the CFD simulation model and normalizing the axial position of the high-pressure hydrogen storage tank. Extract the normalized data along the central axis of the high-pressure hydrogen storage tank, the data including: The axial velocity U c With the inlet velocity U of the fluid inlet Ratio U c / U inlet Distribution data along the central axis of the high-pressure hydrogen storage tank; Data on the distribution of turbulent kinetic energy along the central axis of the high-pressure hydrogen storage tank; The process of normalizing the axial position of the high-pressure hydrogen storage tank includes: dividing the axial length of the high-pressure hydrogen storage tank into a range of [0,1] along the fluid flow direction, and marking the axial position of the high-pressure hydrogen storage tank accordingly.

7. The high-pressure hydrogen storage tank baffle arrangement method based on the jet dissipation transition point according to claim 1, characterized in that, The baffle is coaxially arranged with the high-pressure hydrogen storage tank and is symmetrical about the central axis of the high-pressure hydrogen storage tank. The baffle is an annular baffle and / or has uniformly distributed perforations.

8. The high-pressure hydrogen storage tank baffle arrangement method based on the jet dissipation transition point according to claim 1, characterized in that, The preset ratio threshold is 0.85-0.95; The opening ratio of the baffle is 40%-60%.

9. The method for arranging baffles in a high-pressure hydrogen storage tank based on the jet dissipation transition point according to claim 1, characterized in that, The baffle is inclined, and the distance between the baffle and the central axis of the high-pressure hydrogen storage tank gradually decreases along the fluid flow direction. The inclination angle α between the baffle and the radial plane of the high-pressure hydrogen storage tank ranges from 15° to 30°.

10. A hydrogen storage tank, characterized in that, It includes a tank body and at least one baffle disposed inside the tank body, wherein the position of the baffle is set according to the baffle arrangement method of high pressure hydrogen storage tank based on jet dissipation transition point as described in any one of claims 1-9.

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