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38th International Symposium on Combustion, 2021

作者： Zhang, Meng Wei, Xutao Wang, Jinhua Huang, Zuohua Tan, Houzhang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China MOE Key Laboratory of Thermo-Fluid Science and Engineering Xi'an Jiaotong University Xi'an 710049 China

Recent studies have demonstrated that ammonia could be one of the most promising hydrogen carrier candidates which can be used in large-scale power plants. However, it is challenging to burn ammonia in gas turbines due to its narrow flame stabilization limits. In this study, the blow-off characteristics and flame macrostructure transition behavior of ammonia/air flame (NH₃ flame) and ammonia/methane/air flame (50%NH₃ flame) in a swirl combustor were investigated. Flame structures and flow fields near the blow-off limit were analyzed. Methane/air flame (CH₄ flame) was also examined for comparative purposes. The flow field and instantaneous OH profile were measured with PIV and OH-PLIF technique, respectively. Large eddy simulation (LES) was conducted to extend the understanding of the experimental findings. Results revealed that the NH₃ flame possesses a poor lean flame stability limit which can be largely extended by adding CH₄ in the fuel. Changing swirl number (S) had no apparent effect on the lean blow-off limit (Φ_b) for the NH₃ flame. On the contrary, a clear extension on Φ_b was found for the 50%NH₃ flame when increasing S. Four flame macrostructure modes were identified when decreasing equivalence ratio (Φ). The transition from flame II to flame III ((Φ_tdescribes the transition equivalence ratio) can be considered as the early warning of blow-off for a swirl stabilized flame. For the NH₃ flame, there was no clear flame macrostructure transition at small inlet velocities (U < 3.8 m/sec), i.e., Φ_b ≈ Φt. The difference between Φ_b and (Φ_twas observed as the inlet velocity increased. However, for the 50%NH₃ and CH₄ flames, a clear flame macrostructure transition from flame II to flame III was observed even for a lower inlet velocity. The LES results demonstrated that the NH₃ flame h

关键词： Ammonia

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Non-Hermitian Delocalization in a Two-Dimensional Photonic Quasicrystal

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Physical Review Letters 2024年第26期132卷 263801-263801页

作者： Zhaoyang Zhang Shun Liang Ismaël Septembre Jiawei Yu Yongping Huang Maochang Liu Yanpeng Zhang Min Xiao Guillaume Malpuech Dmitry Solnyshkov Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique School of Electronic Science and Engineering Faculty of Electronics and Information PHOTON-N2 Université Clermont Auvergne CNRS Clermont INP F-63000 Clermont-Ferrand France International Research Center for Renewable Energy and State Key Laboratory of Multiphase Flow in Power Engineering Department of Physics National Laboratory of Solid State Microstructures and School of Physics 75231 Paris France

Theoretical and experimental studies suggest that both Hermitian and non-Hermitian quasicrystals show localization due to the fractal spectrum and to the transition to diffusive bands via exceptional points, respectively. Here, we present an experimental study of a dodecagonal photonic quasicrystal based on electromagnetically induced transparency in a Rb vapor cell. First, we observe the suppression of the wave packet expansion in the Hermitian case. We then discover a new regime, where increasing the non-Hermiticity leads to delocalization, demonstrating that the behavior in non-Hermitian quasicrystals is richer than previously thought.

关键词： Electromagnetically induced transparency Localization Photonics Non-Hermitian systems Quasicrystals

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Effect of Chemical Composition on Adsorption and Agglomeration Characteristics of Ash Particles After Sulfuric Acid Adsorption 9th

Effect of Chemical Composition on Adsorption and Agglomerati...

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9th International Symposium on Coal Combustion, ISCC 2019

作者： Jiang, Jiahao Yan, Yu Guo, Jin Li, Yuesheng Deng, Lei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China Guangdong Institue of Special Equipment Inspection and Research Foshan528251 China Guangdong Institue of Special Equipment Inspection and Research Shunde Institue of Inspection Foshan528300 China

ISBN: (纸本)9789811616563

The low-low temperature electrostatic precipitator has been applied to enhance the efficiency of power plants. In this paper, the influences of chemical constitutions on the adsorption properties of particulate matters with vitriolic acid and the agglomeration after adsorption are researched. Experiments are conducted on a one-dimensional adsorption system, which simulates the working environment of low-low-temperature electrostatic precipitator. The consequences display that the agglomeration between particulate matters in scanning electron microscopy are loose pellets agglomeration together, adhesion of loose pellets to massive particles, and massive particles agglomeration together. For Na and K, the amounts of elements added have little effect on the adsorption of the sulfuric acid by ash particles. For Mg, Fe, and Ca, when the oxide is used as an additive, the adsorption capacity of ash samples to the vitriolic acid was enhanced and the agglomeration phenomenon of the ash granules was more remarkable with increasing elements amounts. In addition, the change of Mg has great impact on vitriolic acid adsorption and granules agglomeration. © 2022, Tsinghua University Press.

关键词： Adsorption

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A large-scale power-to-H 2 -to-power system adopting hydrogen mixed gas turbine for wind accommodation: Process modeling, optimal dispatch and economic feasibility analysis

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International Journal of Hydrogen Energy 2025年 145卷 345-357页

作者： Yanxin Li Xiaoqu Han Yiming Zhang Nikolaos Skordoulias Xuanhua Guo Junjie Yan Sotirios Karellas Emmanuel Kakaras State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China Laboratory of Thermal Processes National Technical University of Athens Athens 15780 Greece Qingdao Huaru Energy Technology Company Limited Qingdao 266071 China Mitsubishi Hitachi Power Systems Europe GmbH Schifferstraße 80 Duisburg 47059 Germany

The high percentage of renewable energy penetration poses volatility and intermittency challenges, making it imperative to explore pathways for large-scale green hydrogen production and utilization. In the present work, a novel power-to-H 2 -to-power (PtH2tP) system is proposed for onshore wind accommodation, incorporating hydrogen mixed gas turbines (HMGTs). An innovative methodology integrating economic and carbon emissions assessment with optimal dispatch is developed, in which the HMGT off-design operational characteristics and policy compensation for green hydrogen are considered. A case study in China demonstrates the feasibility of the PtH2tP system in achieving flexible energy conversion and hydrogen self-sufficiency. Particularly, a levelized cost of electricity of 0.0537 €/kWh and carbon emissions of 0.29 kg CO 2 eq/kWh are observed. The fuel consumption of HMGTs and purchased grid electricity are significant contributors to carbon emissions. A comprehensive sensitivity analysis indicates an optimal hydrogen substitution ratio of 31% as the threshold for balancing economics and environmental benefits.

关键词： Windmill

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Co_(2)N Nanoparticles Anchored on N-Doped Active Carbon as Catalyst for Oxygen Reduction Reaction in Zinc–Air Battery

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Energy & Environmental Materials 2022年第3期5卷 935-943页

作者： Xianli Wu Guosheng Han Hao Wen Yanyan Liu Lei Han Xingyu Cui Jiajing Kou Baojun Li Jianchun Jiang Research Center of Green Catalysis College of ChemistryZhengzhou University100 Science RoadZhengzhou 450001China National Engineering Laboratory for Biomass Chemical Utilization Institute of Chemical Industry of Forest ProductsChinese Academy of ForestryNanjing 210042China College of Science Henan Agricultural UniversityZhengzhou 450002China Davidson School of Chemical Engineering Purdue University480 Stadium Mall DriveIN 47906United States State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University28 Xianning West RoadXi'an 710049China

The development of efficient catalytic electrode toward oxygen reduction reaction(ORR)is still a great challenge for the wide use of zinc–air ***,Co_(2)N nanoparticles(NPs)anchored on N-doped carbon from cattail were verified with excellent catalytic performances for *** onset and half-wave potentials over the optimal catalyst reach to 0.96 V and 0.84 V,*** retention rates of 96.8%after 22-h test and 98.8%after running 1600 s were obtained in 1 M methanol *** functional theory simulation proposes an apparently increased electronic states of Co_(2)N in N-doped carbon layer close to the Fermi *** charge density,favorable adsorption,and charge transfer of intermediates originate from the coexistence of Co_(2)N NPs and N atoms in carbon *** superior catalytic activity of composites also was confirmed in zinc–air *** novel catalytic property and controllable preparation approach of Co_(2)Ncarbon composites provide a promising avenue to fabricate metal-containing catalytically active carbon from biomass.

关键词： catalytically active carbon Co2N nanoparticles N-doping oxygen reduction reaction zinc–air battery

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Experimental Study of an Aluminum Based Three-Dimensional Thermosyphon Heat Sink with Microscale Enhancement Structure

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SSRN 2024年

作者： Yang, Xiaoping Bu, Shichao Jiang, Zhuye Zhou, Yao Sun, Zhen Zhang, Yonghai Wei, Jinjia School of Chemical Engineering and Technology Xi’an Jiaotong University Shaanxi Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China State Key Laboratory of Mobile Network and Mobile Multimedia Technology ZTE Corporation Hillsides China

Heat dissipation is a significant factor limiting the advancement of electronics. Currently, air cooling remains the most widely used method for heat dissipation due to the advantages of low-cost and easy-maintenance. However, the traditional air-cooling method based on all-solid heat sink fails to meet the fast development in thermal power of electronics because its limitation in area expansion by only solid fins. In this study, an aluminum based three-dimensional thermosyphon (3D-TS) coupling boiling-condensation heat transfer and forced air cooling is proposed to overcome the limitation of conventional air cooling methods. Meanwhile, micro pin-fins structure is used to enhance the boiling heat transfer as well as the performance of the 3D-TS. Using the environmentally friendly refrigerant R1233zd(E) as working fluid, the performance of the 3D-TS is experimentally studied and analyzed under different air volume flow rates. The results show that the total thermal resistance decreases firstly and then increases with the heating power, which is mainly dominated by the boiling mode on the substrate. Moreover, the micro pin-fins greatly enhances the boiling heat transfer on the substrate of the 3D-TS, which enables the 3D-TS to reach a minimum thermal resistance of 0.075 K/W and a maximum thermal dissipating power of 650 W with the temperature of the heating source below 85 °C. The 3D-TS proposed in this work is able to meet the cooling requirements of most high-performance chips. This paper provides valuable reference and guidance for the design and optimization of the phase-change devices. © 2024, The Authors. All rights reserved.

关键词： Aluminum

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Novel Fast Predesign Methodology of Centrifugal Compressor Used for Pemfcs Based on 1d Loss Mechanism and Interpretable Machine Learning Models

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SSRN 2024年

作者： Chen, Zhikai Sun, Jieshuai Chen, Ziying Spence, Stephen Peng, Xueyuan Feng, Jianmei School of Energy and Power Engineering Xi'an Jiaotong University Xi'An710049 China School of Mechanical Manufacturing and Biomedical Engineering Trinity College Dublin Dublin 2 Ireland State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'An710049 China

The significant challenge of balancing accuracy, time, and cost has consistently compelled designers to develop more efficient and economical predesign methods. To tackle this issue, a novel predesign method amalgamating one-dimensional (1D) loss model with gradient boosting decision tree (GBDT) model has been proposed. A high-precision 1D loss model was developed and experimentally tested for rapid performance assessment. Furthermore, two machine learning models, named Extreme Gradient Boosting (XGBoost) and Light Gradient Boosting Machine (LightGBM), were trained, and compared to construct surrogate models. Hyperparameter optimization was executed utilizing a Bayesian algorithm to identify the optimal hyperparameter set. Additionally, the Sobol sensitivity analysis and Shapley Additive Explanations (SHAP) based interpretability were used to explore the paramount factors affecting the model's outputs and the interactions among the sensitive parameters. The findings underscore that the blade outlet angle, impeller outlet diameter, impeller outlet width, inlet shroud diameter, and blade inlet angle(shroud) are the most five important parameters influencing the model's indexes. Some beneficial design guidelines are distilled from their feature importance and interactions. and The implement of new design yields powerful evidence for the developed prior knowledge with an increase of 2.5830% in isentropic efficiency and a reduction of 1.5202% in power consumption. © 2024, The Authors. All rights reserved.

关键词： Sensitivity analysis

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Editor, Applied Energy Paper Entitled: "Industrialized Bimetallic Nano Oxygen Carrier for Dual-Stage Hydrogen Production from Mid-Temperature Chemical Looping Reforming"

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SSRN 2024年

作者： Tang, Sanli Gai, Zhongrui Li, Yang Liu, Yunlian Liu, Mingkai Pan, Ying Jin, Hongguang Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China University of Chinese Academy of Sciences Beijing100049 China

Chemical looping methane reforming has emerged as a promising avenue to produce blue hydrogen. Among the various oxygen carriers investigated for this process, Fe2O3 and NiO have garnered significant attention due to their affordability and favorable thermodynamic properties. Usually, such oxygen carriers had satisfactory H2 yields only in the oxidation stage with temperatures over 800 °C. This limitation poses challenges for industrial reactor design and product gas separation. In this study, we present a nanoscale Fe/Ni bimetallic oxygen carrier for dual-stage hydrogen generation from mid-temperature chemical looping methane reforming. The lab-scale oxygen carrier can produce H2 in both the reduction and the oxidation steps, reaching 75% overall H2 purity while reducing the temperature to 500-600 °C. Moreover, the 10-kg scale oxygen carrier achieved >90% CH4 conversion, >78% H2 purity and 2.8-3.5 H2 molecules produced per CH4 molecule. Made into beads, the 10-kg scale oxygen carrier still maintained an outlet H2 purity of >70% with redox stability over 150 cycles. These findings contribute to the advancement of chemical looping methane reforming for blue hydrogen production and supply. © 2024, The Authors. All rights reserved.

关键词： Hydrogen production

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A Three-Dimensional Curve Interface Reconstruction Algorithm for Two-Phase Fluid flow

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SSRN 2024年

作者： Chen, Yujie Gong, Junhua Sun, Dongliang Han, Dongxu Wang, Peng Yu, Bo Tao, Wen-Quan School of Mechanical Engineering Beijing Institute of Petrochemical Technology Beijing102617 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China Key Laboratory of Thermo–Fluid Science and Engineering Ministry of Education School of Energy & Power Engineering Xi’an Jiaotong University Shaanxi 710049 China

The curve interface reconstruction algorithm has received significant attention in the context of two-dimensional two-phase flow. However, it remains absent in the three-dimensional scenario. This paper proposes a novel three-dimensional curve interface reconstruction (CIR) algorithm to address this challenge within structured meshes for the first time. Specifically, a portion of the spherical surface is employed to reconstruct the three-dimensional curve interface segment, with the radius and center coordinates determined by curvature and mass conservation constraints, respectively. To enhance curvature accuracy, a sphere-based iterative reconstruction (SIR) algorithm is proposed to calculate the reconstructed distance function (RDF) for the three-dimensional curve interface. Various tests involving the reconstruction and interface capture of spherical, ellipsoidal, and cubic objects demonstrate that the coupled SIR and CIR (SIR-CIR, simplified by SCIR) method achieves high accuracy, particularly with coarse mesh resolutions. Additionally, the SCIR method offers the advantages of straightforward implementation and coding for interface reconstruction in two-phase flow research. This advantage results in reduced computational costs compared to the coupled volume-of-fluid and level set (VOSET) method, which also utilizes an iterative method to solve RDF. © 2024, The Authors. All rights reserved.

关键词： Spheres

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Dynamics of two-dimensional water flow in angstrom-scale mono and hybrid channels

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Physical Review Fluids 2024年第12期9卷 124201-124201页

作者： Chengzhen Sun Qiyuan Wang Mehdi Neek-Amal Runfeng Zhou Bofeng Bai State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049 China Department of Physics Shahid Rajaee Teacher Training University 16875-163 Lavizan Tehran Iran Departement Fysica Universiteit Antwerpen Groenenborgerlaan 171 B-2020 Antwerpen Belgium

We investigate the dynamics of two-dimensional (2D) water flow within angstrom-scale channels (ASCs), a domain scarcely explored in nanofluidics. Our study focuses on the transformation of monolayer water through hybrid channels made of graphene and MoS2, as well as channels where both walls are made of either graphene or MoS2, with sizes ranging from 6 to 8 Å. We find that the transport of monolayer water through ASCs is significantly hindered under low-pressure conditions at nanoscale timescales. To comprehensively explore the flow dynamics, we introduce a refined extension of the Hagen-Poiseuille equation that accounts for frictional slippage dynamics. Our results indicate that hybrid channels exhibit lower flux compared to monochannels. These findings provide valuable insights into the 2D flow mechanisms of monolayer water molecules, highlighting their distinctive interactions with channel walls and unique structural properties.

关键词： flow confinement Nanofluidics Molecular dynamics Navier-Stokes equation

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