Jichao Li

The integrated development of transportation, culture, and tourism is widely recognized as critical for regional sustainability, yet existing research predominantly uses two-dimensional frameworks and overlooks the unique constraints of highway-dominated pastoral borderlands. Taking Inner Mongolia (2023–2025) as a case study, this research develops a 24-indicator evaluation system and a multi-model analytical framework integrating entropy-weighted TOPSIS, coupling coordination, obstacle degree, and grey relational analysis. This study makes three contributions: (1) It constructs a highway-oriented three-dimensional evaluation framework suited for border regions spanning millions of square kilometres; (2) it distinguishes short-term static obstacles from long-term dynamic factors using an integrated multi-model chain; and (3) it proposes the theoretical concept of ‘Highway–Culture Spatial Matching’ for sparsely populated borderlands. The results reveal a significant spatial gradient, with high coordination in the Hohhot–Baotou–Ordos core and severe lagging in western pastoral areas. The spatial match between highway network accessibility and nomadic cultural heritage sites, rather than resource abundance alone, is the decisive factor determining system coupling. The obstacle degree model pinpoints highway mileage and road network density as primary short-term bottlenecks, while grey relational analysis confirms that the scale of the cultural tourism industry and intangible heritage activation are key long-term drivers. This work provides a quantifiable, evidence-based reference for formulating tiered, sustainable development policies in similar northern frontier ethnic regions, consistent with the UN 2030 Agenda for Sustainable Development.

The wide application of liquid hydrogen as a key energy carrier is severely limited by the reliability of high-pressure and low-temperature pumps. The traditional research on liquid hydrogen pumps relies on empirical analysis of isolated components, but fails to reveal the fundamental failure mechanism of these pumps. This review argues for a paradigm shift in the understanding and design of liquid hydrogen pumps. We systematically decomposed the failure of the liquid hydrogen pump into a thermodynamic-driven, cross-scale cascading process rather than the failure of isolated components. At the molecular level, the extreme thermal physical properties of liquid hydrogen (ultra-low latent heat and surface tension) can lead to widespread nucleation under slight thermal disturbances. At the mesoscopic scale, the initial perturbation is significantly amplified through the nonlinear dynamics of bubble clusters. This amplification is characterized by intense collapse and strong energy concentration due to the low density and low viscosity of liquid hydrogen. At the component level, this enhanced destructive energy will cause faults similar to phase transitions; namely, the liquid lubrication in the bearings will disappear, the seals will shift from viscous blockage to gas diffusion, and at the same time, the damage caused by low-temperature hydrogen cavitation and corrosion to the materials will also occur simultaneously. At the system level, the strong dynamic coupling among the subsystems has led to a nonlinear performance collapse. This cross-scale failure chain reveals the flaws in the classical cavitation theory, which is based on the assumptions of isothermal and inertia dominance. We have expounded the thermodynamic-dominated cavitation state in liquid hydrogen. This state is quantified by the Σ parameter and governs the multimodal behavior of low-temperature cavitation phenomena. To address this complexity, we have proposed a comprehensive framework that integrates multi-scale collaborative simulation and digital twin, combining molecular dynamics, CFD, system dynamics, and targeted experiments. This review proposes a candidate physical framework for addressing the reliability challenges of liquid hydrogen pumps. It also provides a clear roadmap for the next generation of inherently robust cryogenic fluid machinery, and offers a reference for the design of energy systems under other extreme conditions.

The thermodynamic prediction of the fast refueling process for vehicular hydrogen storage cylinders faces the complex problem of modeling multi-layer composite walls. Drawing on the series thermal resistance principle, this paper introduces an equivalent thermal conductivity approach, simplifying the multi-layer structure into homogeneous material. Combined with the real-gas-state equation, a coupled thermodynamic framework combining zero-dimensional gas dynamics and one-dimensional cylinder wall heat transfer is developed. The comparison and verification with the 70 MPa fast charging experimental data have demonstrated that the proposed model exhibits sufficient accuracy and robustness for the problem. By comparing the temperature rise changes of different volume type-III gas cylinders, it was found that the surface area-to-volume ratio (A/V) was the primary geometric factor—the key geometric parameter that governs the temperature rise behavior. Larger volume gas cylinders exhibit more significant temperature rise due to their lower heat dissipation efficiency. A further comparison of the thermal response characteristics between Type-III and Type-IV cylinders demonstrates that the equivalent thermal conductivity is the dominant parameter determining the temperature rise behavior: The lower this coefficient, the stronger the limitation on the cylinder’s heat dissipation capacity, and the more pronounced the temperature rise. The proposed method not only ensures accuracy but also reduces the complexity of the modeling process, providing an efficient theoretical tool for optimizing the refueling strategy and conducting thermal safety assessment of vehicular hydrogen storage systems.

The hydrogen energy industry is rapidly developing, positioning hydrogen refueling stations (HRSs) as critical infrastructure for hydrogen fuel cell vehicles. Within these stations, hydrogen compressors serve as the core equipment, whose performance and reliability directly determine the overall system’s economy and safety. This article systematically reviews the working principles, structural features, and application status of mechanical hydrogen compressors with a focus on three prominent types based on reciprocating motion principles: the diaphragm compressor, the hydraulically driven piston compressor, and the ionic liquid compressor. The study provides a detailed analysis of performance bottlenecks, material challenges, thermal management issues, and volumetric efficiency loss mechanisms for each compressor type. Furthermore, it summarizes recent technical optimizations and innovations. Finally, the paper identifies current research gaps, particularly in reliability, hydrogen embrittlement, and intelligent control under high-temperature and high-pressure conditions. It also proposes future technology development pathways and standardization recommendations, aiming to serve as a reference for further R&D and the industrialization of hydrogen compression technology.

As a zero-carbon energy carrier, hydrogen is playing an increasingly vital role in the decarbonization of maritime transportation. The hydrogen pressure reducing valve (PRV) is a core component of ship-borne hydrogen storage systems, directly influencing the safety, efficiency, and reliability of hydrogen-powered vessels. However, the marine environment—characterized by persistent vibrations, salt spray corrosion, and temperature fluctuations—poses significant challenges to PRV performance, including material degradation, flow instability, and reduced operational lifespan. This review comprehensively summarizes and analyzes recent advances in the study of high-pressure hydrogen PRVs for marine applications, with a focus on transient flow dynamics, turbulence and compressible flow characteristics, multi-stage throttling strategies, and valve core geometric optimization. Through a systematic review of theoretical modeling, numerical simulations, and experimental studies, we identify key bottlenecks such as multi-physics coupling effects under extreme conditions and the lack of marine-adapted validation frameworks. Finally, we conducted a preliminary discussion on future research directions, covering aspects such as the construction of coupled multi-physics field models, the development of marine environment simulation experimental platforms, the research on new materials resistant to vibration and corrosion, and the establishment of a standardized testing system. This review aims to provide fundamental references and technical development ideas for the research and development of high-performance marine hydrogen pressure reducing valves, with the expectation of facilitating the safe and efficient application and promotion of hydrogen-powered shipping technology worldwide.

The hydrogen circulation pump is one of the core components of hydrogen cycle system. To solve the problem of low hydrogen density and the possibility of hydrogen leakage, a vortex hydrogen circulation pump is designed. Taking the three-dimensional flow field of the hydrogen circulation pump as the research object, the CFD (computational fluid dynamics) numerical calculation model of the pump cavity flow field was established, and the internal flow field simulation calculation was performed to analyze the performance characteristics of the hydrogen circulation pump at different speeds and determine. To investigate the effects of flow rates of 80 L/min, 100 L/min, 120 L/min, rotational speeds of 9000 rpm, 11000 rpm, 13000 rpm, 15000 rpm, and the number of vanes of 32, 36, and 40 on the internal flow field of the hydrogen circulating pump. It was found that when the rotational speed was maintained at 15 000 rpm, the flow rate interval was from 80 L/min to 120 L/min, and its pressure difference was always around 270 Pa; When the flow rate is guaranteed to be constant, change the speed of the rotor, the results show that the higher the speed, the higher the differ-ence in pressure between the inlet and outlet; When studying the effect of different number of vanes, the results show that the average static pressure is the most stable when the number of vanes is 36, and the static pressure is stable at 101 345 Pa, while the average value of static pressure is the largest when the number of vanes reaches 40. This work provides ideas for the research of hydrogen cycle system for fuel cells in the future.

To enhance the navigation efficiency of inland new-energy ships and reduce energy consumption and emissions, this study investigates wind load coefficients under 13 conditions, combining a wind speed of 2.0 m/s with wind direction angles ranging from 0° to 180° in 15° increments. Using Computational Fluid Dynamics (CFD) simulations, the wind load is decomposed into along-course (CX) and transverse (CY) components, and their variation with wind direction is systematically analyzed. Results show that CX is maximal under headwind (0°), decreases approximately following a cosine trend, and reaches its most negative value under tailwind (180°). CY peaks at crosswind (90°) and exhibits an overall sinusoidal distribution. Certain wind directions produce a compound effect on the hull, particularly when the crosswind angle approaches 90°. Flow analysis reveals that wind generates a high-pressure zone on the windward side and a low-pressure vortex region on the leeward side, inducing unstable forces and increasing energy consumption. Based on the wind pressure distribution, a targeted structural optimization is proposed to mitigate high-pressure resistance. These findings provide a theoretical basis for hull form optimization and energy-efficient ship design.

The primary methods for hydrogen transportation include gaseous storage and transport, liquid hydrogen storage, and transport via organic liquid carriers. Among these, pipeline transportation offers the lowest cost and the greatest potential for large-scale, long-distance transport. Although the construction and operation costs of dedicated hydrogen pipelines are relatively high, blending hydrogen into existing natural gas networks presents a viable alternative. This approach allows hydrogen to be transported to the end-users, where it can be either separated for use or directly combusted, thereby reducing hydrogen transport costs. This study, based on the GERG-2008 equation of state, conducts experimental tests on the compressibility factor of hydrogen-doped natural gas mixtures across a temperature range of −10 °C to 110 °C and a pressure range of 2 to 12 MPa, with hydrogen blending ratios of 5%, 10%, 20%, 30%, and 40%. The results indicate that the hydrogen blending ratio, temperature, and pressure significantly affect the compressibility factor, particularly under low-temperature and high-pressure conditions, where an increase in the hydrogen blending ratio leads to a notable rise in the compressibility factor. These findings have substantial implications for the practical design of hydrogen-enriched natural gas pipelines, as changes in the compressibility factor directly impact pipeline operational parameters, compressor characteristics, and other system performance aspects. Specifically, the introduction of hydrogen alters the compressibility factor of the transported medium, thereby affecting the pipeline’s flowability and compressibility, which are crucial for optimizing and applying the performance of hydrogen-enriched natural gas in transportation channels. The research outcomes provide valuable insights for understanding combustion reactions, adjusting pipeline operational parameters, and compressor performance characteristics, facilitating more precise decision-making in the design and operation of hydrogen-enriched natural gas pipelines.

To calculate the carrying capacity of spherical hydrostatic bearings, a numerical calculation model was presented. The influence law of dynamic pressure effect on the carrying characteristics of liquid hydrostatic spherical bearings is revealed. Under general working conditions, the dynamic pressure effect caused by the radial eccentricity of the bearing has little influence on the bearing load characteristics parameters; when the minimum width of the gap between the sealing edge is very small and the bearing rotational speed is high, the dynamic pressure effect is more obvious.

Hydrogen is increasingly recognized as a clean and reliable energy vector for decarbonization in the future. In the marine sector, marine solid oxide fuel cells (SOFCs) that employ hydrogen as an energy source have already been developed. In this study, a multi-channel plate-anode-loaded SOFC was taken as the research object. A three-dimensional steady-state computational fluid dynamics (CFD) model for anode-supported SOFC was established, which is based on the mass conservation, energy conservation, momentum conservation, electrochemical reactions, and charge transport equations, including detailed geometric shapes, model boundary condition settings, and the numerical methods employed. The polarization curves calculated from the numerical simulation were compared with experimental results from the literature to verify the model’s accuracy. The curved model was applied by enlarging the flow channels or adding blocks. Numerical calculations were employed to obtain the current density, temperature distribution, and component concentration distribution under the operating conditions of the SOFC. Subsequently, the distribution patterns of various physical parameters during the SOFC operation were analyzed. Compared to the classical model, the temperature of the curved model was reduced by 1.3%, and the velocities of the cathode and anode were increased by 4.9% and 5.0%, respectively, with a 2.42% enhancement in performance. The findings of this study provide robust support for research into and the application of marine SOFCs, and offer they insights into how we may achieving “dual carbon” goals.