检索结果-内蒙古大学图书馆

Effects of methanol and its cracked gas on ammonia consumption and NOx emission under high pressure

International Journal of Hydrogen Energy 2025年 136卷 491-500页

作者： Yin, Geyuan Shen, Shujie Zhan, Haochen Hu, Erjiang Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China

The mole fraction profiles for NH3/syngas were measured at 5.0 MPa and different blending ratios and compared with NH3/methanol to understand the effects of methanol and its cracked gas on ammonia oxidation and micro-species behavior. A kinetic model proposed in our previous work is validated against the measured data. The model demonstrates remarkable accuracy in predicting the concentration profiles of NH3 and NOx under all conditions. Moreover, a superior performance of methanol control is found at low temperatures, while syngas has a better performance at high temperatures. The onset temperature of methanol is lower than that of syngas. When the temperature reaches 950 K, H2 can provide more active OH than methanol and accelerate the ammonia consumption through the reaction cycle. Moreover, methanol triggers NO formation at 50 K lower than syngas, and the peak molar concentration of NO is lower than that of syngas at high blending ratios. At a substitution ratio of 50 %, NO generated by an ammonia-methanol mixture exhibits an "N"-shaped trend, while it monotonically increases with temperature with syngas blending. The peak concentrations of N2O with methanol are higher than those from syngas, especially at substitution ratios of 1. % and 25 %. © 2025 Hydrogen Energy Publications LLC

关键词： Nitrogen oxides

来源：评论

学校读者我要写书评

暂无评论

Concurrently Boosting Activity and Stability of Oxygen Reduction Reaction Catalysts via Judiciously Crafting Fe-Mn Dual Atoms for Fuel Cells

引用

Nano-Micro Letters 2025年第4期17卷 275-289页

作者： Lei Zhang Yuchen Dong Lubing Li Yuchuan Shi Yan Zhang Liting Wei Chung-Li Dong Zhiqun Lin Jinzhan Su International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049People’s Republic of China Department of Physics Tamkang UniversityNew Taipei CityTaiwan 25137People’s Republic of China Department of Chemical and Biomolecular Engineering National University of SingaporeEngineering Drive 4Singapore 117585Singapore

The ability to unlock the interplay between the activity and stability of oxygen reduction reaction(ORR)represents an important endeavor toward creating robust ORR catalysts for efficient fuel ***,we report an effective strategy to concurrent enhance the activity and stability of ORR catalysts via constructing atomically dispersed Fe-Mn dualmetal sites on N-doped carbon(denoted(FeMn-DA)-N-C)for both anion-exchange membrane fuel cells(AEMFC)and proton exchange membrane fuel cells(PEMFC).The(FeMn-DA)-N-C catalysts possess ample dual-metal atoms consisting of adjacent Fe-N_(4)and Mn-N_(4)sites on the carbon surface,yielded via a facile doping-adsorption-pyrolysis *** introduction of Mn carries several advantageous attributes:increasing the number of active sites,effectively anchoring Fe due to effective electron transfer to Mn(revealed by X-ray absorption spectroscopy and density-functional theory(DFT),thus preventing the aggregation of Fe),and effectively circumventing the occurrence of Fenton reaction,thus reducing the consumption of ***(FeMn-DA)-N-C catalysts showcase half-wave potentials of 0.92 and 0.82 V in 0.1.M KOH and 0.1.M HClO_(4),respectively,as well as outstanding *** manifested by DFT calculations,the introduction of Mn affects the electronic structure of Fe,down-shifts the d-band Fe active center,accelerates the desorption of OH groups,and creates higher limiting *** AEMFC and PEMFC with(FeMn-DA)-N-C as the cathode catalyst display high power densities of 1.60 and 746 mW cm^(-2),respectively,underscoring their promising potential for practical *** study highlights the robustness of designing Fe-containing dual-atom ORR catalysts to promote both activity and stability for energy conversion and storage materials and devices.

关键词： Doping-adsorption-pyrolysis Dual-atom catalysts Oxygen reduction reaction Fuel cells

来源：评论

学校读者我要写书评

暂无评论

Thermodynamic and environmental analysis of the hydrogen and combustible gas production in supercritical water partial oxidation system of coal

引用

Energy 2025年 326卷

作者： Li, Yifeng Xing, Guowei Liu, Shi Guo, Shenghui Ge, Zhiwei Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Supercritical water partial oxidation (SCWPO) is an eco-friendly coal treatment technology that lowers the temperature needed for complete coal gasification, promotes hydrogen output, enables targeted regulation of gaseous product composition, and eliminates gaseous pollutants. Current researches mainly focus on experiments and numerical simulations, with limited exploration in thermodynamics. The present study establishes an auto-thermal SCWPO cogeneration system for Hongliulin coal, employs sensitivity analysis to refine system parameters, and utilizes Life Cycle Assessment to evaluate the environmental impact of the hydrogen production system. When the outlet temperature of the SCWPO reactor increases, the preheating water flow and equivalence ratio (ER) enhance, the fraction of H2 in the gas product rises;conversely, the fraction of the combustible gas (CH4+CO + H2) rises. The SCWPO system can be precisely tailored to yield high-purity hydrogen or combustible gas by modulating the amount of oxygen input. The system of combustible gas production is capable of generating 241.67 GJ h−1.of energy and attaining a cold gas efficiency of 81.62 % when the ER is 0.25. The hydrogen production system can generate 1.04.38 kg h−1.of H2 and 206 t h−1.of steam at 0.5 MPa and 1.0 °C for an ER of 0.6. The optimized hydrogen production system achieved 90.97 % energy efficiency and 59.33 % exergy efficiency. The standard Global Warming Potential through carbon capture technology is 0.087 (kg H2)−1. The system developed in this paper benefits the industrial application of SCWPO and the optimization of subsequent processes. © 2025 Elsevier Ltd

关键词： River pollution

来源：评论

学校读者我要写书评

暂无评论

A multi-physics model-based approach for macro-structured surface design to enhance heat transfer in R41.A flash spray cooling systems

引用

International Journal of Heat and Mass Transfer 2025年 247卷

作者： Ye, Ying-Dong Lin, Xiang-Wei Zhou, Zhi-Fu Liu, Maochang Chen, Bin Lu, Youjun Jing, Dengwei State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Refrigerant flash spray cooling, which offers high heat flux dissipation at low temperatures, holds significant potential for thermal management of high-power electronic devices. While surface structure design can further amplify heat transfer performance, the lack of systematic methodologies to address the complexities of spray cooling has hindered progress. This study establishes a multi-physics computational framework that couples two-phase flash spray dynamics, liquid film heat transfer, and solid heat conduction to systematically optimize macro-structured surfaces. After validating the model against experimental data, the effects of surface geometry (flat, square, straight and pyramid fins) and dimensional parameters on cooling performance were analyzed. The pyramid structure demonstrated superior performance, achieving a 9 K reduction in surface temperature and a 70 % increase in effective heat transfer coefficient compared to the flat surface. Quantitative analysis revealed that optimal macro-structured design hinges on maximizing effective heat transfer area while ensuring uniform liquid film distribution via controlled droplet dynamics. Further parametric studies on nine pyramid geometries identified a base length of 1.mm and height-to-edge ratio of 0.7 as the optimal configuration, balancing heat transfer enhancement and manufacturing costs through a newly proposed Composite Heat Transfer Factor (CHTF). This work provides a mechanistic framework for designing enhanced surfaces in spray cooling systems, bridging critical gaps in both theoretical understanding and {1. application. © 2025 Elsevier Ltd

关键词： Film cooling

来源：评论

学校读者我要写书评

暂无评论

Experimental and simulation study of H2 crossover in PEM water electrolysis for high-pressure hydrogen production up to 20 MPa

引用

International Journal of Hydrogen Energy 2025年 135卷 499-506页

作者： Wu, Jiazhe Zhang, Guoao Dong, Boyu Chang, Yuhao Chen, Yubin International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi 710049 China

High-pressure proton exchange membrane (PEM) water electrolysis offers considerable advantages, particularly in enabling direct integration with hydrogen storage and transportation systems while eliminating the need for external mechanical compressors. However, H2 crossover is a bottleneck that induces high H2-in-O2 content and low overall efficiency during high-pressure PEM water electrolysis. This study investigates H2 crossover in PEM water electrolysis by combining in situ measurements and numerical simulations over a differential pressure range of 0–20 MPa. A linear correlation was observed between hydrogen crossover and current density within the range of 0–1.A cm−2. The cathodic hydrogen mass transfer coefficient was determined to range from 1.6 to 3.2 mm s−1. and the hydrogen solubility was estimated as 1.1.× 1.−3 mmol m−3 Pa−1. The results highlight the importance of optimizing mass transfer and reducing hydrogen solubility within the cathode catalyst layer to mitigate H2 crossover during high-pressure PEM water electrolysis. © 2025 Hydrogen Energy Publications LLC

关键词： Diffusion in solids

来源：评论

学校读者我要写书评

暂无评论

Numerical study of specific C-shaped heat exchanger using porous medium and coarse mesh coupling method

引用

International Journal of Thermal Sciences 2025年 210卷

作者： He, Shaopeng Wang, Shiqi Wang, Mingjun Tian, W.X. Qiu, S.Z. Su, G.H. State Key Laboratory of Multiphase Flow in Power Engineering School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an710049 China

Porous medium method is an effective simplified approach for the heat exchanger simulation when the numerous tubes and complex structures bring unacceptable computational resources to full-scale simulation. However, for the specific C-shaped heat exchanger, the tube side resistance and flow distribution characteristics that significantly affects the heat transfer and natural circulation performance cannot be obtained by the traditional porous medium method coupled with the one-dimensional node model for tube side. It is urgent to develop a new coupling method that can not only simplify modeling and calculation, but also obtain tube side high-resolution flow heat transfer characteristics. This study presents a novel calculation method which couples the porous medium mesh and the tube side coarse mesh. The coupling method was then applied to a typical C-shaped passive residual heat removal heat exchanger (PRHR HX), which is significant to the stable operation and the mitigation of accident conditions in the nuclear power plant. The coupling calculation method was validated against the full-scaled simulation and data from scaled-down experiment. The average relative error of heat transfer power is 2.1.% under steady state conditions. Under transient conditions, the average absolute error of the fluid temperature and wall temperature are less than 6 K. Then the 3D thermal-hydraulic characteristics of PRHR HX was studied. Owing to a greater gravitational pressure head, the mass flow rates in the extended tubes surpass those in the shorter tubes by a relative deviation of 27.4 %. The upper horizontal tube's heat exchange capacity constitutes approximately 70 % of the total power, leading to enhanced natural circulation. The outlet temperatures from various tubes tend to equalize. The boiling area gradually extended down along the heat transfer tubes. Our work would present an innovative calculation method to the numerical study and design optimization of the C-shaped heat

关键词： Nuclear power plants

来源：评论

学校读者我要写书评

暂无评论

Hydrogen production performance optimization for direct-coupled photovoltaic electrolysis systems based on a novel 3D opto-electro-thermal model

引用

Applied Energy 2025年 392卷

作者： Wang, Hao Wang, Weiding Lin, Chuanjie Lai, Yongquan Li, Changchen Xu, Ziyou Yang, Yuanbo Yang, Yimin Dong, Wenxuan Su, Jinzhan International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering School of Energy & Power Engineering Xi'an Jiaotong University Xi'an710049 China

Photovoltaic-powered electrolysis systems represent a promising approach for large-scale renewable energy storage, with direct-coupled systems offering particular advantages in terms of reduced system complexity and cost. However, a mismatch issue between photovoltaic (PV) and electrolysis (EC) modules of these systems could be caused by suboptimal structural design and {1. rate control strategies, leading to a significant reduction in hydrogen production performance. While these problems could potentially be addressed through numerical simulation, existing low-dimension models are overly simplified due to the assumptions of spatial homogeneity, failing to adequately capture the intricate coupling mechanisms among optical, thermal, electrical and gas-liquid {1. phenomena in these complex systems. In this study, a novel 3D opto-electro-thermal model has been developed for direct-coupled systems, utilizing semiconductor drift-diffusion equations and a gas-liquid two-phase {1. model within each grid cell. This advanced model facilitates comprehensive performance assessments during the optimization of the fundamental system structure (PV-EC), including the evaluation of novel system configurations that integrate photovoltaic/thermal (PV/T) and contact-based thermal designs. Additionally, it could help to streamline {1. rate control by optimizing the relative sizing between the membrane electrode assembly (MEA) of EC and PV modules. The results demonstrate that the PV/T-EC Non-thermal integration structure achieves the maximum Solar-to-Hydrogen efficiency (STH). Moreover, by setting the relative sizing at 2.25 %, maintaining the {1. rate in a wide range without precise control could be sufficient to achieve outstanding and stable STH under real-world fluctuating conditions. This allows the {1. rate control strategy to be effectively streamlined. The findings could provide guidance for optimizing hydrogen production performance by refining system structure and {1.

关键词： Model structures

来源：评论

学校读者我要写书评

暂无评论

Flocculation of suspended cohesive particles in Rayleigh-Bénard turbulence

引用

Physical Review Fluids 2025年第2期10卷 024305-024305页

作者： Han Huang Shuaiqi Zhao Rui Zhang Binbin Pei Kunpeng Zhao Bofeng Bai State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China Key Laboratory of Mechanics on Disaster and Environment in Western China The Ministry of Education of China Lanzhou University Lanzhou 730000 China

We employ a four-way coupled numerical approach to investigate the dynamics of suspended cohesive particles in Rayleigh-Bénard turbulence. The Stokes drag, cohesive, and direct contact forces between primary particles are captured in detail, yielding the phenomena of flocs' aggregation, breakage, and deformation. The momentum and thermal exchange between primary particles and the fluid are considered based on the Source-in-Cell method. We found that the initial increase of the average floc size indicates a temporary flocculation phase, which is followed by an equilibrium phase where the average floc size becomes stable, reflecting the balance between aggregation and breakage. Different from the traditional perspective, which attributed the local accumulation of particles to their gravity, we found that the suspended particles still tend to accumulate in the bottom hot boundary layer region. This accumulation is primarily driven by the temperature-induced variation in aggregation strength and the nonuniform spatial distribution of floc inertia. Additionally, the stronger cohesion yields a reduction in momentum intensity of the thermal plumes, primarily due to the more pronounced weakening of fluid momentum by the larger flocs.

关键词： Momentum

来源：评论

学校读者我要写书评

暂无评论

Infectious cough droplet dynamics in a makeshift hospital isolation ward

引用

Physics of Fluids 2025年第2期37卷

作者： Norvihoho, Leslie Kojo Liu, Yi Yin, Jing Zhu, Xin-Gang Yu, Hai-Tao Wang, Qi-Di Chen, Bin Zhou, Zhi-Fu State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an710049 China China Nuclear Power Engineering Co. Ltd. Beijing China

The COVID-1. pandemic highlighted the need for rapidly deployable healthcare facilities, leading to increased use of modular construction methods. Nonetheless, knowledge about airflow patterns and the spread of bioaerosols in these wards remains insufficient, potentially heightening the risk of cross-infection among healthcare workers and patients. This paper presents a ventilation design for a modular negative-pressure ward aimed at reducing the spread of infectious particles. We investigate the effects of various ventilation designs, patient postures (sitting and supine), and air changes per hour (ACH) on the spread of infectious cough droplets in an airborne infection isolation room using large eddy simulation and the Eulerian-Lagrangian model. Findings show that ceiling exhaust grilles (design 2) resulted in the lowest radial dispersion (3.64 m) at 1. ACH, while sidewall exhausts (baseline) performed best at higher ACH levels. Seated patients had quicker droplet evaporation compared to those in a supine position. The best setups for reducing droplet survival included exhaust grilles at the bed's bottom and ceiling, maintaining a minimum of 1. ACH. Cases 5 and 1., with grilles over the patient's head and at the bed's bottom, showed the lowest concentrations of DPM, under 0.008 km−3 near the source and less than 0.001.km−3 mid-room. Sitting posture consistently led to lower DPM concentrations. This research emphasizes the critical role of exhaust placement in reducing droplet re-circulation and transmission risks, ultimately contributing to improved ventilation strategies and infection control in AII rooms. © 2025 Author(s).

关键词： Ceilings

来源：评论

学校读者我要写书评

暂无评论

Novel numerical method establishment and performance evaluation for rotary adsorption and desorption wheel for carbon capture

引用

Applied Thermal engineering 2025年 274卷

作者： Gao, Rongze Wang, Limin Wang, Chang'an Tang, Chunli Li, Yuhang Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an710049 China School of Mechanical Engineering Xi'an Shiyou University Xi'an710065 China

Due to the great compactness and ease of operation, the rotary adsorption and desorption wheel (RADW) is applicable for carbon capture in power plants using temperature swing adsorption (TSA). Commercial CFD-based software such as Fluent is commonly used to evaluate the RADW performance but the computing time is too long. However, few studies have focused on the computational efficiency and stability of complicated coupled heat and mass transfer processes in the RADW. A detailed iteration format and method for independent programming is urgently needed for both rapid design calculation and real-time performance monitoring in power plants. A novel rapid solution method using the mixed implicit and explicit (MIE) strategy to achieve the cyclic steady state (CSS) in the rotary bed was proposed, which can be used for heat transfer, mass transfer, and the coupled transfer processes. A comparison in terms of accuracy and efficiency was made between Fluent and the proposed method. In order to illustrate the applicability and universality of the proposed method, characteristics of the mass and temperature distribution in the RADW packed with amine-functionalized G3M were obtained, and the effects of different parameters on the adsorption and desorption behavior of RADW were studied. The correlation for the adsorption efficiency calculation operation was fitted, with which the adsorption efficiency under different operating conditions can be quickly obtained. © 2025

关键词： Osmosis

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：