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SSRN 2025年

作者： Yang, Zhongmei Wang, Xiaoyang Mu, Xiaojiang Hong, Congjie Miao, Lei Novel Battery Materials Research Center of Engineering Technology State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures School of Physical Science and Technology Guangxi University Nanning530004 China State Key Laboratory of Multiphase Flows in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Ammonia-hydrogen fuel, recognized as a quintessential zero-carbon green energy source, presents significant challenges in storage and transportation due to the inherent safety risks associated with hydrogen fuel handling. Leveraging ammonia's potential as an efficient hydrogen storage medium, we focus on developing a novel technology for on-site ammonia decomposition to produce hydrogen under ambient conditions. Here, we employ a straightforward electrochemical process to catalytically decompose ammonia into hydrogen and nitrogen at standard temperature and pressure, with ammonia in its gaseous form directly volatilized from an aqueous ammonia solution. A CeO2@NiCu₃/NF electrocatalyst capable of efficient ammonia decomposition at an impressively low potential (1.27 V vs. RHE) was synthesized. This catalyst demonstrated a Tafel slope of 41.5 mV dec-1, significantly improving electrolysis efficiency. It also exhibited excellent stability during 21 hours of continuous operation. Density Functional Theory (DFT) analysis revealed that the unique composite structure of CeO2 and NiCu3 features a d-band position similar to platinum, optimizing the adsorption-desorption balance of ammonia. Furthermore, the impact of ammonia on the combustion characteristics of hydrogen under different cracking ratios was investigated from an application perspective. Combustion kinetics simulations were performed to evaluate the effects of ammonia on the ignition delay time (IDT) and laminar flame speed (LFS) of hydrogen. The results indicate that the presence of small amounts of NH3 has a negligible effect on the ignition delay time of hydrogen but significantly reduces its laminar flame *** study provides a valuable experimental foundation for advancing the practical utilization of hydrogen as a sustainable fuel while addressing the challenges associated with ammonia-hydrogen energy systems. © 2025, The Authors. All rights reserved.

关键词： Ammonia

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Instantaneous mixing characteristics of binary mixtures differing in density in a gas-solid fluidised bed

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Particuology 2020年第6期18卷 63-71页

作者： Zhen Wan Youjun Lu Hao Wang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049ShaanxiChina

Characterisations of instantaneous mixing behaviours in fluidised beds with binary mixtures has many *** studied the instantaneous mixing characteristics of binary mixtures in a 2-D quasi gas-solid fluidised bed using a capacitance probe *** method enabled the quantitative assessment of instantaneous mixing behaviours,including mixing index,rate,and *** kinds of binary mixtures of similar size but different density were used for the transient and steady fluidisation experiments in a bubbling fluidised *** mixing curves of initially segregated binary mixtures were acquired,and the instantaneous characteristics for the entire process were *** equation was proposed to describe the mixing process and predict the mixing degree over *** comparing experiments with different working conditions,the effects of superficial gas velocity and density ratio on the mixing in the centre and at the wall of the fluidised bed were *** the stable fluidisation stage,the axial concentration profiles of the mixtures were obtained,and the mechanisms of mixing were *** showed that the mixing level increased logarithmically with time and eventually reached a relatively stable *** the superficial gas velocity and reducing the density ratio promoted mixing and reduced mixing *** superficial gas velocities tended to mix the mixtures well and quickly,regardless of the density ratio of the two components.

关键词： Binary mixtures Fluidised bed Mixing Instantaneous characteristics

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Effect of the Density Difference on Fluid Distribution in Layered Rock Samples

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Energy & Fuels 2025年第9期39卷 4412-4420页

作者： Yongfei Yang Tonghui Liu Yingwen Li Weichen Sun Hai Sun Lei Zhang Junjie Zhong Kai Zhang Jun Yao State Key Laboratory of Deep Oil and Gas China University of Petroleum (East China) Qingdao 266580 P. R. China；Research Center of Multiphase Flow in Porous Media School of Petroleum Engineering China University of Petroleum (East China) Qingdao 266580 P. R. China Geosteering & Logging Research Institute Sinopec Matrix Corporation Qingdao 266071 P. R. China Research Center of Multiphase Flow in Porous Media School of Petroleum Engineering China University of Petroleum (East China) Qingdao 266580 P. R. China

During geological CO2storage, gravity segregation due to fluid density differences significantly affects the efficiency and safety of the process. This can result in premature CO2breakthrough, reduced storage efficiency, and increased leakage risks. This study aims to investigate how gas migrates in layered heterogeneous reservoirs over time due to prolonged density differences and to assess the resulting impact on fluid distribution. We use artificially layered heterogeneous sandstone cores for experimentation. After completing gas injection and water flooding experiments, the core was positioned with the low permeability layer (LPL) at the top and the high permeability layer (HPL) at the bottom for an extended period. Because the effects of density differences are not easily discernible during gas–water two-phase flow under typical driving forces, we applied micro-CT imaging technology to visualize and analyze how density differences influence gas flow within the core. The results demonstrate that during the static placement period following displacement, gas clusters exhibit different flow behaviors at the pore throats. Most gas clusters struggle to overcome the Jamin effect and enter into the upper pores; a few large-volume gas clusters, driven by density differences, partially pass through the throats into the upper pores, while the remaining portions are stranded within the throats, leading to a snap-off phenomenon; while some gas clusters successfully overcome the Jamin effect and enter the upper pores in significant numbers. The experimental findings indicate that the LPL effectively hinder the upward migration of the nonwetting phase gases from bottom and fluid density differences significantly influence gas–water distribution changes. This study provides critical insights for optimizing CO2storage and offers a new perspective on fluid behavior in layered heterogeneous reservoirs.

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Experimental investigation of enhanced heat transfer for fined circular tube heat exchanger with rectangular fins

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Journal of Harbin Institute of Technology(New Series) 2006年第4期13卷 385-390页

作者：李永星杨冬陈听宽 State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University

Presents a set of data for flow and heat transfer of finned-tube bundle under the condition of high air flow velocity. Air flow and heat transfer over a 4 × 4 （ columns × rows） finned-tube heat exchanger with rectangular fins was investigated experimentally in a wind tunnel with constant wall temperatures condition. The air flow velocity based on the minimum flow cross-section area over flow channel ranged from 13.8 to 50. 2 m/s, the heal transfer rate ranged from 21.8 to47. 1 kW, and the air temperatures increase ranged from 10. 9 to 19. 8 ℃. The present results were compared with results calculated from correlations proposed by CSPE. For air flow velocity less than 25 m/s, these two results of heat transfer agreed well with each other, whereas for larger velocity, our test data disagreed with the CSPE correlations. For the friction factor, present data are much higher than the predicted results in the whole range. Finally, correlations for friction factors and heat transfer coefficients are DrODosed based on the experimental results.

关键词： haeat exchanger rectangular finned-tube enhanced heat transfer friction factor

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Study on the Enhancement Effect of Dielectric Barrier Discharge on the Premixed Methane/Oxygen/Helium Flame Velocity

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Plasma Science and Technology 2015年第12期17卷 1019-1026页

作者：穆海宝喻琳李平汤成龙王金华张冠军 State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical EngineeringXi'an Jiaotong University State key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University

Recently,plasma-assisted combustion has become a potentially applicable technology in many combustion *** this paper,a dielectric barrier discharge（DBD） plasma generator is designed to explore the effect of plasma on the CH4 oxidation process,and several properties of combustion are ***,in the presence or absence of plasma discharge,physical appearance of the flame is examined and ***,the flame propagation velocity is calculated by the flame front extracted from the imaging data with the Bunsen burner ***,the main molecular components and their intensity variation in the flame and the plasma zones are identified with an emission spectrograph to analyze the effect of active species on the combustion *** also discuss the possible kinetic regime of plasma-assisted *** results imply that plasma discharge applied to the premixed CH_4/O_2/He mixture significantly raises the flame speed with equivalence ratios ranging from 0.85 to 1.10,with the flame speed improved by 17%to 35%.It can be seen that plasma can improve methane oxidation efficiency in the premixed fuel/oxidizer,especially at a low equivalence ratio.

关键词： combustion flame Oxygen equivalence appearance Velocity scenarios burning camera hydrocarbon

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Prediction of Heat Transfer Rates for Shell-and-Tube Heat Exchangers by Artificial Neural Networks Approach

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Journal of Thermal Science 2006年第3期15卷 257-262页

作者： Qiuwang WANG Gongnan XIE Ming ZENG Laiqin LUO State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Shaanxi Xi＇an710049 China

This work used artificial neural network(ANN)to predict the heat transfer rates of shell-and-tube heatexchangers with segmental baffles or continuous helical baffles,based on limited experimental *** BackPropagation (BP) algorithm was used in training the *** network configurations were *** deviation between the predicted results and experimental data was less than 2%.Comparison withcorrelation for prediction shows ANN *** is recommended that ANN can be easily used to predict theperformances of thermal systems in engineering applications,especially to model heat exchangers for heattransfer analysis.

关键词： heat transfer rate Artificial Neural Network shell-and-tube heat exchanger back propagation

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Theoretical investigation on the steady-state natural circulation characteristics of a new type of pressurized water reactor

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Nuclear Science and Techniques 2006年第5期17卷 314-320页

作者： GOU Jun-Li QIU Sui-Zheng SU Guang-Hui JIA Dou-Nan State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇an 710049 China

This article presents a theoretical investigation on the steady-state natural circulation characteristics of a new type of pressurized water reactor. Through numerically solving the one-dimensional steady-state single-phase conservative equations for the primary circuit and the steady-state two-phase drift-flux conservative equations for the secondary side of the steam generator, the natural circulation characteristics were studied. On the basis of the pre- liminary calculation analysis, it was found that natural circulation mass flow rate was proportional to the exponential function of the power and that the value of the exponent is related to the operating conditions of the secondary side of the steam generator. The higher the outlet pressure of the secondary side of the steam generator, the higher the pri- mary natural circulation mass flow rate. The larger height difference between the core center and the steam generator center is favorable for the heat removal capacity of the natural circulation.

关键词：核反应堆压水堆稳态自然循环高度差理论研究

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Stability of stratified flow and slugging in horizontal gas-liquid flow

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Progress in Natural Science:Materials International 2005年第11期15卷 1026-1034页

作者： GU Hanyang and GUO Liejin (State key laboratory of multiphase flow in power engineering, Xi’an Jiaotong University, Xi’an 710049, China) State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

A transient one-dimensional two-fluid model is proposed to investigate numerically the interfacial instability and the onset of slugging for liquid-gas flow in a horizontal duct. In the present model, the effects of surface tension and transverse variations in dynamic pressure are taken into account. The evolution of interfacial disturbances is displayed and compared with the linear viscous Kelvin-Helmholtz stability analyses. It shows that interfacial wave is more instable due to the non-linear effect. The model predicts well the stability limit of stratified flow in comparison with the experimental data, and also automatically tracks the onset of slugging. The results show that the initiation of hydrodynamic slugging is related to local interfacial instability. Based on the cycle of slugging, a model for slug frequency is presented, which predicts the trends of slug frequencies with gas/liquid flow rate well in comparison with the available data. The effects of physical properties on slugging have been examined. It is found that with the increase in the gas viscosity and liquid density the slugging would be inhibited, whereas, with the increase in liquid viscosity and gas density, the slugging can be promoted.

关键词： two-fluid model Kelvin-Helmholtz stability interfacial instability onset of slugging gas-liquid stratified flow.

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Recovery of waste heat in cement plants for the capture of CO2

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Frontiers of Chemical Science and engineering 2012年第1期6卷 104-111页

作者： Ruifeng DONG Zaoxiao ZHANG Hongfang LU Yunsong YU State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

Large amounts of energy are consumed during the manufacturing of cement especially during the calcination process which also emits large amounts of CO2. A large part of the energy used in the making of cement is released as waste heat. A process to capture CO2 by integrating the recovery and utilization of waste heat has been designed. Aspen Plus software was used to calculate the amount of waste heat and the efficiency of energy utilization. The data used in this study was based on a dry process cement plant with a 5-stage preheater and a precalciner with a cement output of 1 Mt/y. According to the calculations： 1） the generating capacity of the waste heat recovery system is 4.9MW. 2） The overall CO2 removal rate was as high as 78.5%. 3） The efficiency of energy utilization increased after the cement producing process was retrofitted with this integrated design.

关键词： cement industry waste heat recovery utiliza-tion CO2 removal

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Experimental Investigation on Hydrophobic Behavior of Carbon Spheres Coated Surface Made from Microplastics

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Journal of Renewable Materials 2021年第12期9卷 2159-2174页

作者： Peng Liu Bin Bai Cui Wang Yunan Chen Zhiwei Ge Wenwen Wei Hui Jin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China

In this paper,a simple method to plate a hydrophobic coating on the inner surface of a small-scaled tube was proposed,where the coating consisted of carbon *** common plastics polystyrene,polycarbonate and polyethylene were used as the feedstocks to be processed in supercritical water in a quartz tubular *** reaction,the contact angle of droplet on the inner surface of the quartz tube was turned out to be over 100°,significantly larger than that of the blank tube 54°.When processing polystyrene in the 750℃ supercritical water for 10 min,the largest contact angle was obtained,up to 145°.Besides,in this sample,the size of carbon spheres was smallest,about 2.09μm diameter on *** comparing among different types of plastics under the same condition,the contact angle of surface made from PC took the dominant position over that of PS and PE,124°,100°and 90°,*** the sample made from PC,carbon spheres adhered into a mountainlike shape,producing a binary geometric ***,this research could be helpful in the discussion of plastic waste management and carbon spheres fabrication with low cost.

关键词： Plastic wastes hydrothermal method carbon spheres supercritical water hydrophobicity

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