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Measurement of laminar burning velocities and analysis of flame stabilities for hydrogen-air-diluent premixed mixtures

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Chinese Science Bulletin 2009年第5期54卷 846-857页

作者： HU ErJiang HUANG ZuoHua HE JiaJia JIN Chun MIAO HaiYan WANG XiBin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

The laminar burning velocities and Markstein lengths of the hydrogen-air-diluent mixtures were meas-ured at different equivalence ratios (0.4―1.5), different diluents (N2, CO2 and 15%CO2+85%N2) and di-lution ratios (0, 0.05, 0.10 and 0.15) by using the outwardly expanding flame. The influences of flame stretch rate on the flame propagation characteristics were analyzed. The results show that both the laminar burning velocities and the Markstein lengths of the hydrogen-air-diluent mixtures decrease with the increase of dilution ratio. The decrease in Markstein lengths means that adding diluents into the hydrogen-air mixtures will decrease the diffusional-thermal instability of the flame front. For a specified dilution ratio, the laminar burning velocities give their maximum values at an equivalence ratio of 1.8. The Markstein lengths increase with the increase of the equivalence ratio monotonously regardless of the diluents. The study shows that CO2 as the diluent has a greater impact on the laminar flame speed and the flame front stability than N2 as the diluent.

关键词：氢气空气混合火焰特性燃烧速度稳定性

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Modeling and prediction of ultrasonic attenuations in liquid-solid dispersions containing mixed particles with Monte Carlo method

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Particuology 2019年第2期17卷 84-91页

作者： Jianfei Gu Fengxian Fan Yunsi Li Huinan Yang Mingxu Su Xiaoshu Cai Institute of Particle and Two-Phase Flow Measurement/Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology Shanghai 200093 China

We develop a theoretical model for predicting the ultrasonic attenuation in the liquid-solid system containing mixed particles. The ultrasonic attenuation coefficient is obtained by counting the number of phonons that reach the receiver. Using the Monte Carlo method (MCM), numerical simulations were performed to predict the ultrasonic attenuations with not only a single particle type but also monodisperse and polydisperse mixed particles. The simulation results for the systems with a single particle type were compared with various standard models. The results show that they agree well at relatively low particle volume concentrations (within 10%). For systems with mixed particles, the particle volume concentrati on was found to in crease to around 10%, and the variation of the ultrasonic attenuation agai nst the mixing ratio yields a nonlinear trend. Moreover, the ultrasonic attenuation is significantly affected by particle properties. The numerical results also show that both the particle type and particle size distribution should be carefully taken into account in the dispersions with polydisperse mixed particles, where the MCM can give a more direct description of the physics of sound propagation compared with the conventional models.

关键词： Ultrasound Ultrasonic attenuation Monte Carlo method Particle size measurement

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Evaluating the chemical kinetics of aluminium/alumina/water reactions using molecular dynamics

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Computational Materials Science 2025年 257卷

作者： Zhao, Hao Zhang, Yingjia Liu, Yuncong Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University No.28 Xianning West Road Shaanxi Xi'an 710049 China

Strength of aluminium in generating heat and hydrogen through water reaction highlight its potential as a green hydrogen carrier, but the formation of a passive oxide layer (alumina) inhibits further reactions thus hydrogen yield. This study employs reactive molecular dynamics (MD) simulations with the ReaxFF force field to investigate interactions between water and alumina-coated aluminium surfaces at temperatures ranging from 1000 K to 2500 K. Analysis of diffusion-driven reaction kinetics shows that hydrogen generation is primarily controlled by hydrogen atom diffusion within the aluminium bulk. Higher temperatures significantly accelerate both diffusion and reaction rates, shifting the mechanism from diffusion-limited to chemically controlled. Atomic-level reaction pathway analysis, using an in-house atom status tracing code, reveals the dynamic evolution of aluminium atom states. The results emphasize the roles of hydrogen and oxygen diffusion and indicate that O–H bond cleavage mainly proceeds through internal atomic diffusion. These findings offer detailed atomic-scale insight into the aluminium-water reaction, capturing both oxidizer diffusion and thermal effects. The study highlights the importance of thermal activation in enhancing reaction efficiency and safety, reinforcing aluminium's potential for green hydrogen production in carbon–neutral energy systems. © 2025 Elsevier B.V.

关键词： Alumina Aluminium Chemical kinetics Interface Molecular dynamics ReaxFF

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Distribution of void fraction for gas-liquid slug flow in aninclined pipe

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Nuclear Science and Techniques 2001年第2期12卷 143-148页

作者： XIA Guo-Dong1, ZHOU Fang-De2, HU Ming-Sheng2 (1 College of Environmental and Energy engineering, Beijing Polytechnic University, Beijing 100022 2 State key laboratory of multiphase flow in power engineering, Xi’an Jiaotong University, xi’an 710049) College of Environmental and Energy Engineering Beijing Polytechnic University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University

In order to investigate the effect of inclination angle on the spatial distribution of phases, experiments on gas-liquid two-phase slug flow in an inclined pipe were carried out by using the optical probe and an EKTAPRO 1000 high speed motion analyzer. It has been demonstrated that the inclination angle and the mixture velocity are important parameters to influence the distribution of void fraction for upward slug flow in the inclined pipe. At high mixture velocity, the gas phase profile is axial symmetry in the cross-section of the pipe. This is similar to that for vertical slug flow. In contrast, most of the gas phase is located near the upper pipe wall at low mixture velocity. By measuring the axial variation of void fraction along the liquid slug, it can be concluded that there is a high void fraction wake region with length of 3～4D in the front of liquid slug. In the fully developed zone of liquid slug, the peak value of the void fraction is near the upper wall.

关键词：气-液二相流斜管相分布

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Impact of bimetallic synergies on Mo-doping NiFeOOH:Insights into enhanced OER activity and reconstructed electronic structure

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Frontiers in Energy 2024年第6期18卷 850-862页

作者： Jingkuo Qu Yuchen Dong Tuo Zhang Chang Zhao Liting Wei Xiangjiu Guan International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049China

NiFe(oxy)hydroxide(NiFeOOH)is recognized as a highly active non-precious metal catalyst in alkaline water electrolysis due to its exceptional catalytic *** this work,high valence molybdenum(Mo)is introduced to improve the electronic structure and enhance the electrical conductivity of NiFeOOH for oxygen evolution reaction(OER).The introduction of Mo results in a Mo-doped NiFeOOH catalyst with a significantly reduced overpotential of 205 mV at 10 mA/cm^(2)and a Tafel slope of 31.7 mV/dec,enabling stable operation for up to 170 *** empirical experiment and theory simulations are employed to gain insight into the 3d-electron interactions between molybdenum and nickel(Ni),iron(Fe)in Mo-doped *** results indicate that Mo-doping enhances the valence states of Ni and Fe,leading to a shift in the d-band center of the bimetallic active *** modification affects the transformation of Mo-doped NiFeOOH into theγ-NiFeOOH active *** potent combination lends credence to its potential suitability and utility in OER applications.

关键词： Mo doping NiFe(oxy)hydroxide(NiFeOOH) bimetallic synergies oxygen evolution reaction(OER) electronic structure

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Measurement of laminar burning velocities of iso-butanol-air mixtures

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Chinese Science Bulletin 2010年第19期55卷 2046-2056页

作者： FENG PengFei GU XiaoLei HUANG ZuoHua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

The laminar burning velocity of iso-butanol-air mixtures was measured under different initial pressures,initial temperatures and equivalence ratios using high-speed schlieren photography and outwardly propagation flame in a constant volume combustion *** on the analysis of stretched flame propagation speed and stretch rate,the laminar burning velocities and Markstein lengths of iso-butanol-air flames are *** accordance,with photos of flame,an analysis of flame stability and the influencing factors is carried *** results show that the laminar burning velocity is decreased with the increase of initial pressure and is increased with the increase of initial *** maximum value of laminar burning velocity is presented at the equivalence ratio of *** Markstein length is decreased with the increase of equivalence *** specified equivalence ratio,the Markstein length is decreased with the increase of initial temperature and initial ***,the flame instability is increased with the increase of equivalence ratio,initial temperature and initial pressure.

关键词：层流燃烧速度空气混合物速度测定异丁醇火焰传播速度初始压力初始温度当量比

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Understanding the Initial Decomposition Pathways of the n-Alkane/Nitroalkane Binary Mixture

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Chinese Journal of Chemistry 2013年第8期31卷 1087-1094页

作者： Yulei Guan Ying Zhang Chunhai Yi Bolun Yang Department of Chemical Engineering State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shannxi 710049 China

Addition of nitroalkanes into n-alkanes can lower the activation barriers of free-radical production and acceler- ate the decomposition of n-alkanes at relatively low temperatures. Four initial decomposition mechanisms of the n-butane/nitroethane binary mixture were proposed for the promoting effect and considered theoretically at the B3LYP, BB1K, BMK, MPW1K, and M06-2X levels with MG3S basis set. Energetics above was compared to high-level CBS-QB3 and G4 calculations. Calculated results confirm the feasibility of the four initial decomposition pathways：（I） the C--NO2 bond rupture of nitroethane to produce ethyl and .NO2, （II） HONO elimination from nitroethane followed by decomposition to .OH and .NO, （1II） rearrangement of nitroethane to ethyl nitrite which further dissociates into CH3CH20. and .NO, and （IV） direct hydrogen-abstraction ofnitroethane with n-butane.

关键词： free radical initial decomposition mechanism computational chemistry hydrogen-abstraction bimol-ecular

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Experimental and numerical investigation of two phase ejector performance with the water injected into the induced flow

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International Journal of Advanced Nuclear Reactor Design and Technology 2020年 2卷 15-24页

作者： Chen, WeiXiong Huang, ChenXi Bai, YuPing Chong, DaoTong Yan, JunJie Liu, JiPing State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

When injectors are used in petroleum industries or sea water desalination system, it is a special case that the induced gas is accompanied by water, the ejector is in two-phase operation. In the present study, the ejector performance at two phase flow is investigated experimentally and numerically. The results indicate that: the entrainment ratio would decrease when the water is injected into the induced flow, as well as the pressure ratio. The maximum decrement of entrainment ratio is around 40.5% at sub-critical mode when the motive pressure is 1.0 MPa, the induced pressure is 0.2 MPa, liquid-air ratio is 22%. For the pressure ratio, the maximum decrement is 62.5% when the motive pressure is 1.0 MPa, the induced pressure is 0.5 MPa, liquid-air ratio is 2.87%. However, the lower the induced pressure is, the more obvious the effect of mass flow rate on entrainment rate is, while the effect on pressure ratio is just opposite. Moreover, the performance becomes worse in sub-critical mode than that in critical mode. The effect of NXP on ejector performance also has been analyzed. There exists an optimum NXP whether the two phase flow ejector is in critical mode or sub-critical mode. The optimum NXP for entrainment ratio enlarges from 3.6 mm to 4.4 mm with the increase of water mass flowrate, and is bigger than that of single phase ejector (the optimum NXP is 2.8 mm). This study may provide a beneficial reference for the operation of supersonic ejectors on two phase flow. © 2020 Xi'an Jiaotong University

关键词： Two phase flow

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The Behavior and Characteristics of the InterfacialWaves in Gas-Liquid Two-Phase Separated flowThrough Downward Inclined Rectangular Channel

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Journal of Thermal Science 1998年第1期7卷 29-36页

作者： Guangjun Li Lienjin Guo Xuejun Chen(national laboratory of multiphase flow in power engineering,Xi’an Jiaotong University,Xi’an,710049,China) National Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China

An experimental investigation on the behavior and characteristics of interfacial waves in downward inclined rectangular channel was conducted. The interfacial waves were traced and measured by us-ing conductance technique. The wav patterns were distinguished and defined. The characteristics of the interfacial waves, such as time-averaged film thickness, wave height, wave propagation speed,wavlength and wave frequency, were systematically examined in terms of gas and liquid superficial volumetric fiuxes. The effect of the inclination and flow channel geometry of the test section on the interfacial wav was also investigated.

关键词： liquid film thickness gas-liquid two-phase flow interfacial waves experiment study

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A numerical model of thermal analysis for woven wire screen matrix heat exchanger

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Cryogenics 2009年第9期49卷 482-489页

作者： Shuangtao, Chen Yu, Hou Hongli, Zhao Lan, Xi State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

Woven wire screen matrix heat exchanger (WSMHE) is a kind of compact, light-weight and high-efficiency matrix heat exchanger (MHE) for cryogenic applications. This paper presented a numerical model for the design and thermal analysis of WSMHE. The influence of wall thermal resistance, axial conduction, parasitic heat load and properties variation was taken into account, which is neglected in the traditional effectiveness-NTU method but important for compact cryogenic heat exchangers. The proposed numerical method is verified by effectiveness-NTU method under specific conditions, then it is tested according to experiment data, and a well agreement was obtained. Based on this model, a detailed analysis was performed on WSMHEs. The analysis results show that the axial conduction might result in evident decrease of effectiveness at low flow rate region;the effectiveness of WSMHEs with large flow rate could be remarkably enhanced by increasing its length;the influence of parasitic heat load varied little throughout of the flow rate region. Furthermore, the numerical model presented in this paper can be developed to the design and thermal analysis of small partition wall type heat exchangers. © 2009 Elsevier Ltd. All rights reserved.

关键词： Thermoanalysis

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