Vehicle-mounted liquid hydrogen storage tank with built-in microcavity phase change self-adaptive anti-shaking plate

Abstract

The invention discloses a vehicle-mounted liquid hydrogen storage tank with a built-in microcavity phase change self-adaptive anti-shaking plate. A plurality of functional units are arranged on the anti-shaking surface of the anti-shaking plate. Each unit comprises a micro-cavity, a critical medium packaged in the cavity and a super-lyophobic nano-structure layer covering a cavity opening. When the liquid hydrogen sloshes intensively and the local dynamic pressure exceeds a threshold value, the liquid hydrogen intrudes into the microcavity to trigger the critical medium to generate phase change, and a micro vortex or cavitation bubble group is generated to efficiently dissipate the sloshing kinetic energy; when the shake is weakened, the process reversibly recovers. The process is completely passive, and external control and energy are not needed. Preferably, the anti-oscillation plate adopts a partitioned elastic sub-plate structure connected by a flexible hinge, and the flow field distribution is optimized through thermally induced micro-deformation. According to the invention, broadband, self-adaptive and high-reliability oscillation suppression in an extremely low-temperature environment is realized, the impact peak value of oscillation force is obviously reduced, and the safety and economy of a vehicle-mounted liquid hydrogen storage and transportation system are improved.

Description

Technical Field

[0001] This invention belongs to the field of cryogenic liquid storage and transportation technology, specifically relating to an internal anti-sloshing device and structural design for a vehicle-mounted large-capacity liquid hydrogen storage tank. Background Technology

[0002] During the road transportation of liquid hydrogen, the on-board storage tanks experience complex inertial forces due to vehicle acceleration, braking, and turning, causing severe sloshing of the liquid hydrogen inside. This sloshing generates impact forces (sloshing force), posing a serious threat to the structural integrity of the tank, vehicle stability, and safety. Therefore, suppressing liquid hydrogen sloshing is a key technical objective in the design of on-board hydrogen storage systems. Currently, the industry commonly employs two technical methods to achieve this goal. The first is a built-in fixed mechanical anti-sloshing structure, such as perforated baffles or transverse or longitudinal partitions. The advantage of this type of solution is its simple structure and high reliability. However, its core drawback is that its geometry and porosity are fixed during the design phase, meaning its sloshing suppression performance (such as damping coefficient and effective sloshing frequency band) cannot be changed during tank operation. When vehicle operating conditions become complex and variable, and the induced liquid sloshing frequency exceeds its optimal design range, its sloshing suppression effect will significantly decrease, failing to achieve effective coverage across a wide frequency range. The second type is an active sloshing suppression system. This system uses a sensor array installed inside the tank to monitor changes in liquid level or pressure in real time. The controller then processes the data to drive pumps, valves, and other actuators to generate a counterforce to counteract sloshing. Theoretically, this solution has adaptive capabilities. However, in the extreme low-temperature environment of liquid hydrogen (approximately -253°C), the signal stability of the electronic sensors and the reliability of the controller and actuators face severe challenges. Furthermore, such systems are complex in structure, consume a lot of energy, and are expensive to manufacture, introducing additional potential failure points. Under the harsh conditions of long-term vibration and shock in vehicles, the long-term operation and maintenance costs and risks cannot be ignored.

[0003] In summary, existing technologies face significant bottlenecks in meeting the core requirements of high reliability, adaptability, and wide-frequency-domain sway suppression in extreme low-temperature environments: fixed structures lack adaptability, and active systems suffer from poor reliability and excessive cost. Therefore, a novel technological approach is urgently needed to fundamentally overcome the shortcomings of existing solutions and develop a vehicle-mounted liquid hydrogen storage tank anti-sway solution that combines passive reliability, wide-frequency adaptive sway suppression capabilities, and suitability for engineering applications. Summary of the Invention

[0004] To address the problems and shortcomings of existing fixed vehicle-mounted liquid hydrogen storage tanks, this invention provides a vehicle-mounted liquid hydrogen storage tank with a built-in microcavity phase change adaptive anti-sloshing plate. Through a fully passive structure based on fluid kinetic energy-triggered microcavity phase change dissipation, the technical challenge of achieving high reliability and wide-frequency adaptive anti-sloshing in a liquid hydrogen environment is fundamentally solved.

[0005] The solution to the technical problem of this invention is as follows: an on-board liquid hydrogen storage tank with a built-in microcavity phase change adaptive anti-sloshing plate, comprising a storage tank body and an anti-sloshing plate disposed inside it, wherein multiple functional units are disposed on the anti-sloshing surface of the anti-sloshing plate; each functional unit comprises: a microcavity formed below the anti-sloshing surface; a critical medium encapsulated within the microcavity, the critical medium having phase change critical characteristics at the operating temperature of the storage tank; and an inlet structure for enabling the liquid in the storage tank to enter the microcavity and interact with the critical medium when the local dynamic pressure exceeds a threshold due to external excitation, triggering the critical medium to transform from a first state to a second state containing bubbles or vortices; wherein the state transformation of the critical medium is used to dissipate the kinetic energy of liquid sloshing, so as to achieve adaptive adjustment of the damping force.

[0006] Preferably, the inlet structure is a superhydrophobic nanostructure layer covering the opening of the microcavity.

[0007] Preferably, the superhydrophobic nanostructure layer comprises a nanowire array or a nanopillar array.

[0008] Preferably, the critical medium is a mixture of helium-3 and helium-4 that is at its superfluid critical point at liquid hydrogen temperature. Preferably, the molar fraction of helium-3 in the mixture is 3%-8%.

[0009] Preferably, the anti-sway plate includes multiple functional sub-plates, each of which has a functional unit on its anti-sway surface, and adjacent functional sub-plates are connected by an elastic connector. Preferably, the elastic connector is a flexible hinge.

[0010] Preferably, the storage tank is a vehicle-mounted storage tank for storing liquid hydrogen. Preferably, the vehicle-mounted storage tank is a large-capacity storage tank.

[0011] The beneficial effects of this invention are as follows: 1. It achieves fully passive, adaptive, wide-band, and efficient sloshing suppression. Through the design of a superhydrophobic nanostructure-critical medium microcavity unit, the damping force of the anti-sloshing plate can be triggered and adjusted in real time by the fluid's own kinetic energy, completely eliminating dependence on any external sensors, controllers, and energy sources. This structure can automatically respond to wide-band sloshing excitations from low to high frequencies. Theoretical analysis and fluid simulation show that, compared with traditional fixed porous anti-sloshing plates, the solution of this invention can reduce the peak value of the maximum impact force of liquid sloshing in the tank by about 35%-50% under typical working conditions, and broaden the effective sloshing suppression frequency band by at least one time (e.g., Figure 6 (As shown in the comparison curve).

[0012] 2. By eliminating all electronic and mechanical moving parts that are prone to failure at extreme low temperatures, the system reliability is significantly improved. Theoretically, no maintenance is required throughout its entire lifecycle, significantly reducing the risk of failure and operating costs. The solution avoids the high-precision sensing, high-speed computing, and precision actuation modules required by complex active control systems, simplifying the system architecture. Although there are initial costs associated with functional surface micromachining, the zero-power operation and maintenance-free characteristics give it a competitive advantage in total lifecycle cost and provide space for lightweight design of the tank support structure.

[0013] 3. The core working mechanism is based on physical phase transitions. All materials and structures are designed for the cryogenic environment of liquid hydrogen, and in particular, a mixture of chemically stable helium isotopes is used as the critical medium, ensuring the stability and long lifespan of the technology under extreme conditions. Further, the partitioned elastic structure design, through a physical feedback mechanism of thermally induced micro-deformation and flow field self-optimization, achieves self-organized collaborative sway suppression on a macroscopic scale, enhancing robustness in handling complex and random swaying conditions. This passive intelligent behavior requires no software algorithm support but significantly improves overall performance. Attached Figure Description

[0014] Figure 1 : A schematic cross-sectional view of the overall structure of the vehicle-mounted liquid hydrogen storage tank of the present invention.

[0015] Figure 2 : Enlarged cross-sectional view of a single functional unit (microcavity, critical medium, superhydrophobic nanolayer).

[0016] Figure 3 Schematic diagram of the three stages of the functional unit's working process (normal state, triggering, phase transition dissipation).

[0017] Figure 4 : Schematic diagram of an anti-sway plate using a partitioned elastic structure (functional sub-plates connected by flexible hinges).

[0018] Figure 5 Cross-sectional view of an optimized functional unit employing a multi-layer gradient microcavity structure.

[0019] Figure 6 The following is a comparison curve of the anti-sway performance of the anti-sway plate of this invention and the traditional anti-sway plate at different swaying frequencies.

[0020] The following are the labels in the diagram: 1. Tank body; 1-1. Tank outer wall; 1-2. Insulation layer; 1-3. Connection part; 2. Anti-sway plate; 3. Anti-sway plate metal substrate; 4. Microcavity; 5. Critical medium; 6. Superhydrophobic nanostructure layer; 7. Microvortex / bubble cluster; 8. Functional sub-plate; 8-1. Microcavity array; 9. Elastic connector or flexible hinge; 10. Liquid hydrogen. Detailed Implementation

[0021] During vehicle operation, the liquid hydrogen inside the onboard liquid hydrogen storage tank experiences severe sloshing due to acceleration, braking, and turning. The impact force generated by this sloshing not only threatens the structural safety of the storage tank but also affects the vehicle's handling stability. A long-standing technical challenge in this field is how to design an anti-sloshing device that requires no external energy source or complex control, and can autonomously adjust its damping characteristics based on the intensity of the sloshing, under the extreme cryogenic conditions of liquid hydrogen, to achieve highly reliable, wide-frequency adaptive sloshing suppression. The following will combine the attached... Figure 1-5 The technical solutions of the present invention will be described in detail through specific embodiments. It should be understood that these embodiments are only used to illustrate the core principles and preferred solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Example

[0022] This embodiment provides a basic structure for an on-board liquid hydrogen storage tank with a built-in microcavity phase change adaptive anti-sway plate. (See also...) Figure 1 This diagram illustrates an overall arrangement of the vehicle-mounted liquid hydrogen storage tank of the present invention. The tank body 1 is a vacuum-insulated pressure vessel suitable for storing liquid hydrogen. Inside the tank body 1 (including the outer wall 1-1 and the insulation layer 1-2), at least one anti-sway plate 2 is arranged axially and / or radially. This anti-sway plate 2 is supported by a support structure (e.g., Figure 1 The connecting part 1-3 is fixed to the inner wall of the storage tank by welding or threading at its root. The core feature of the anti-sway plate 2 is that a large number of functional units 3 are arranged in a certain pattern on its anti-sway surface 2-1.

[0023] Figure 2 This is an enlarged cross-sectional view of a single functional unit 3. As shown in the figure, functional unit 3 mainly includes the following parts: A microcavity 4 is formed inside the anti-sway plate substrate (i.e., the part below the anti-sway surface 2-1). It can be prepared by femtosecond laser precision machining, chemical etching, or micro-electrical discharge machining, and its shape is preferably cylindrical or prismatic, with a diameter D between 5 micrometers and 20 micrometers and a depth H between 10 micrometers and 30 micrometers. A critical medium 5 is encapsulated within the microcavity 4. The key characteristic of this medium is that it is near the phase transition critical point at the operating temperature of the storage tank (i.e., the liquid hydrogen temperature, approximately -253°C), and is extremely sensitive to small external energy or pressure disturbances. A preferred critical medium 5 is helium-3 (³He) and helium-4 (³He) 4 A mixture of He and He. By adjusting the mixing ratio, its superfluid transition temperature (λ line) can be precisely controlled. For example, when the molar fraction of He is in the range of 3% to 8%, the mixture is exactly in the critical region of transition from normal fluid to superfluid state in the liquid hydrogen temperature range, with extremely high thermal conductivity and extremely low viscosity, and its phase change behavior is exceptionally sensitive to pressure and thermal disturbances.

[0024] In this embodiment, the inlet structure is a superhydrophobic nanostructure layer 6 covering the opening of the microcavity 4. This layer is formed by growing a vertically aligned array of carbon nanotubes (CNTs) around the opening of the microcavity 4 and on the damping surface 2-1 using plasma-enhanced chemical vapor deposition (PECVD) combined with a template method. The nanotubes have a diameter of approximately 80-120 nm, a height of approximately 8-15 μm, and a spacing of approximately 100-200 nm. Subsequently, the CNT array is modified with low-temperature fluorinated silane to make its surface contact angle with liquid hydrogen greater than 150°, exhibiting superhydrophobic properties.

[0025] The working principle of the above functional units combined Figure 3 Please provide an explanation. Figure 3 In the following scenarios: (a) Normal state (low dynamic pressure): When liquid hydrogen 4 flows smoothly, the local dynamic pressure is low. Due to the presence of the superhydrophobic nanostructure layer 6, the contact area between liquid hydrogen 4 and the sloshing-suppressing surface 2-1 is very small, resulting in extremely low flow resistance. Liquid hydrogen 4 cannot penetrate the microcavity 4. The critical medium 5 maintains its initial superfluid or critical state. (b) Triggering state (high dynamic pressure): When vehicle movement causes liquid hydrogen 4 to slosh violently, the local flow velocity increases, and the dynamic pressure exceeds the design threshold (this threshold is determined by the gaps between nanostructures, surface tension, and the phase transition pressure of the critical medium). At this time, liquid hydrogen 4 overcomes the superhydrophobic barrier and is forced into the microcavity 4. (c) Phase transition dissipation: The invading cryogenic liquid hydrogen 4 undergoes violent non-equilibrium heat exchange with the critical medium 302. This disturbance instantly disrupts the original phase equilibrium of the medium 302, inducing local phase transition instability. For example, in a superfluid helium mixture, a local transition from a superfluid state to a normal fluid state may be triggered, accompanied by the generation of strong vortices; or in other media systems, rapid micro-vaporization may occur, generating nanobubbles. This phase transition process absorbs a large amount of kinetic energy (in the form of latent heat, etc.) from the sloshing of liquid hydrogen. At the same time, at the outlet of microcavity 4, a large number of micro-vortices or bubble groups generated by the phase transition will violently disturb the external mainstream field. This strong disturbance at the microscale efficiently converts the ordered macroscopic kinetic energy of the large-scale sloshing into the thermal energy of the microscale vortex and dissipates it rapidly, thereby instantaneously generating a significant additional flow resistance in the region where functional unit 3 is located, forming a dynamic hydrodynamic lock. The stronger the sloshing, the more triggering units there are, and the greater the overall damping; the sloshing weakens, the triggering stops, the medium gradually recovers, and the damping decreases. When the vehicle movement causes the liquid hydrogen in the storage tank to slosh laterally (perpendicular to the axis), the liquid hydrogen must flow around the anti-sloshing plate 2. The presence of the anti-sloshing plate greatly increases the tortuosity and surface area of ​​the flow path, thereby initially dissipating the sloshing energy through friction and impact.

[0026] Furthermore, to optimize the overall effect of adaptive sway suppression and improve reliability, the sway guard 2 can be designed as a zoned elastic structure. (See also...) Figure 4The anti-sway plate 2 can be formed by connecting multiple functional sub-plates 8 through elastic connectors 8-1. Each functional sub-plate 8 integrates the aforementioned array of functional units 3. The elastic connectors 8-1 can be flexible hinges made of metal foil sheets with a thickness of micrometers (such as Invar steel sheets). When a unit on a certain sub-plate 201 is triggered in large numbers due to strong shaking, and the local temperature rises slightly (ΔT<1K), the sub-plate 201 will produce a slight thermal expansion deformation, which will drive itself or adjacent sub-plates to undergo a slight angular deflection through the elastic connectors 8-1. This deflection can actively optimize the impact direction of the subsequent liquid hydrogen flow, promote a more uniform distribution of shaking energy on the entire anti-sway plate 2, thereby stimulating more functional units 3 to work together and achieve system-level self-organized optimization of shaking suppression. Example

[0027] Based on Embodiment 1, this embodiment further optimizes the structure of functional unit 3 to improve its triggering sensitivity and energy dissipation efficiency. (See also...) Figure 5 This paper illustrates a preferred multi-layered gradient microcavity structure. A single functional unit 3 contains not just one microcavity, but is composed of multiple sub-microcavities (301a, 301b, 301c) stacked vertically with decreasing pore sizes from top to bottom. The sub-microcavities are connected by finer channels, forming an overall funnel shape. A critical medium 5 fills the entire multi-layered microcavity system. The structure exhibits gradient-triggered operation: 1. When the local dynamic pressure reaches the first threshold, liquid hydrogen 4 first invades the uppermost sub-microcavity 4a with the largest pore size, triggering a preliminary phase change in the medium of that region and generating primary damping. 2. If the shaking continues to intensify and the dynamic pressure further increases, liquid hydrogen 4 will progressively penetrate the lower, smaller-pore sub-microcavities (301b, 301c). Due to the smaller pore size, larger specific surface area, and stronger confined space effect of the lower cavities, the intensity of the phase change and the energy dissipation efficiency are significantly higher than those of the upper cavities. 3. This design enables the damping response of a single functional unit 3 to exhibit a non-linear, step-like increase, allowing for more precise and efficient matching of swaying excitations of varying intensities. Compared to a single-cavity structure, it achieves a wider dynamic adjustment range and higher energy dissipation density within the same space.

[0028] Furthermore, the critical medium 5 can be encapsulated using microcapsule composite phase change materials. Specifically, the aforementioned helium-3 / helium-4 mixture is encapsulated in nanoscale thick-walled microcapsules made of silica or polymer materials. A large number of these microcapsules are then mixed with ultrafine thermally conductive powder (such as nanodiamond particles) and filled into the microcavity 4. The microcapsule walls ensure the sealing of the medium, and their brittle fracture characteristics constitute an additional pressure-triggered mechanism: when the dynamic pressure is sufficiently high, some microcapsules rupture, instantly releasing the medium and causing a more intense direct interaction with liquid hydrogen. The thermally conductive powder accelerates the diffusion and dissipation of heat, preventing localized heat accumulation that could lead to functional unit failure.

[0029] Through the specific embodiments described above, this invention, employing a core design of a superhydrophobic nanostructure-critical medium microcavity, achieves damping adjustment entirely triggered by the fluid's own kinetic energy, requiring no external sensors, controllers, or energy supply. This fundamentally eliminates the risk of electronic device failure in the active control system at cryogenic liquid hydrogen, resulting in a significant improvement in system reliability. Since each functional unit has a defined hydrodynamic trigger threshold and responds independently, the anti-sway plate can automatically cover a wide range of sway excitations from low to high frequencies. When the dominant sway frequency changes, units in different regions and with different thresholds are selectively triggered, consistently providing effective damping. Theoretical analysis and preliminary fluid simulations show that, compared to traditional fixed porous anti-sway plates, this invention can reduce the peak value of the maximum sway force impact under typical operating conditions by approximately 35%-50% and broaden the effective sway suppression bandwidth by at least double. Figure 6 A schematic comparison of the normalized damping force response curves of a traditional anti-sway plate and the anti-sway plate of this invention under sinusoidal excitation at different frequencies shows that the curve of this invention is flatter and maintains a higher value in the high-frequency range. Since the core working mechanism is based on physical phase transition and has no moving mechanical parts, wear and fatigue problems are avoided. Furthermore, a helium mixture is used as the critical medium, which is chemically extremely stable at extreme low temperatures and has a reversible phase transition process, theoretically allowing for unlimited cycles of use. The partitioned elastic structure design achieves self-optimization of the macroscopic flow field through minute thermally induced deformation. This intelligent behavior, derived from physical feedback, requires no complex algorithms but significantly enhances the system's ability to cope with complex random swaying.

[0030] It should be noted that the above embodiments and accompanying drawings are merely illustrative examples of the core principles and key structures of a vehicle-mounted liquid hydrogen storage tank with a built-in microcavity phase change adaptive anti-sway plate according to the present invention. The accompanying drawings are simplified schematic diagrams, intended to clearly illustrate the structural, process, or data flow relationships related to the innovative points of the technical solution, and are not intended to limit the complete form of the actual product. This specification focuses on the innovative technical means necessary to achieve the invention's objectives and solve the technical problems. While auxiliary or common-sense details such as the specific mechanical design of the support structure, the installation and sealing of the anti-sway plate and the tank body, other alternative processes for microcavity processing, and the setting of conventional insulation layers, which can be achieved by those skilled in the art without creative effort, are not elaborated upon, they should all be understood as naturally included in the specific implementation of the present invention and fall within the protection and implementation scope of this technical solution.

Claims

1. A vehicle-mounted liquid hydrogen storage tank with a built-in microcavity phase change adaptive anti-sway plate, comprising a tank body and an anti-sway plate disposed therein, characterized in that, The anti-sway plate has multiple functional units on its anti-sway surface. Each of the functional units includes: Microcavities formed below the sway-suppressing surface; A critical medium encapsulated within the microcavity, the critical medium having phase change critical characteristics at the operating temperature of the storage tank; And an inlet structure for enabling the liquid in the tank to enter the microcavity and interact with the critical medium when the local dynamic pressure exceeds a threshold due to external excitation, triggering the critical medium to transform from a first state to a second state containing bubbles or vortices; The morphological transformation of the critical medium is used to dissipate the kinetic energy of liquid sloshing, thereby achieving adaptive adjustment of the damping force.

2. The vehicle-mounted liquid hydrogen storage tank according to claim 1, characterized in that, The inlet structure is a superhydrophobic nanostructure layer covering the opening of the microcavity.

3. The vehicle-mounted liquid hydrogen storage tank according to claim 2, characterized in that, The superhydrophobic nanostructure layer includes a nanowire array or a nanopillar array.

4. The vehicle-mounted liquid hydrogen storage tank according to any one of claims 1-3, characterized in that, The critical medium is a mixture of helium-3 and helium-4 that is at the superfluid critical point at liquid hydrogen temperature.

5. The vehicle-mounted liquid hydrogen storage tank according to claim 4, characterized in that, Preferably, the molar fraction of helium-3 in the mixture is 3%-8%.

6. The vehicle-mounted liquid hydrogen storage tank according to claim 1, characterized in that, The anti-sway plate includes multiple functional sub-plates, and the functional unit is provided on the anti-sway surface of each functional sub-plate. Adjacent functional sub-plates are connected by elastic connectors.

7. The vehicle-mounted liquid hydrogen storage tank according to any one of claims 1-3, characterized in that, The storage tank is a vehicle-mounted storage tank used for storing liquid hydrogen.

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