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作者： Zhang, Xinyi Tang, Chenglong Yu, Huibin Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'An Jiaotong University Xi'an 710049 China

Experiments were conducted in a constant volume bomb filled with isooctane/n-butanol blend-air mixtures over a wide range of n-butanol blending ratios, equivalence ratios, and initial pressures. High-speed schlieren photography was used to measure the critical radius for the onset of flame-front instability. Results show that, for a given n-butanol blending ratio, cellular instabilities appear earlier and the critical Peclet number, which represents the onset of instability, is decreased with the increase of the initial pressure and equivalence ratio. Under fuel-rich conditions, the critical Peclet number increases with the increase of the n-butanol blending ratio. Theoretical calculation of the critical Peclet number was also conducted to interpret the effects of n-butanol on the flame-front instabilities of the blends. Results show that, for rich mixture conditions, with the increase of the n-butanol blending ratio, the overall activation energy of the mixtures is decreased and, thus, the thermal-diffusional instabilities are suppressed. While under fuel-lean conditions, the thermal-diffusional instabilities are favored. As a consequence, with an increasing n-butanol blending ratio, the critical Peclet number is expected to be decreased under fuel-lean conditions and increased under fuel-rich conditions. © 2014 American Chemical Society.

关键词： Mixtures

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Laminar flame speeds and flame structure of syngas using OH-PLIF

Laminar flame speeds and flame structure of syngas using OH-...

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9th Asia-Pacific Conference on Combustion, ASPACC 2013

作者： Fu, Jin Jing, Wu Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'An Jiaotong University Xi'an 710049 China

The effects of flame stretch and hydrogen dynamic stretch on laminar Bunsen flames, especially for the mixture with high H2 fraction, were studied in this paper. OH-PLIF was used to examine the flame reaction zone by visualizing the OH radical concentrated zone. Experiments were conducted at equivalence ratios ranging from 0.5 to 1.6 in the laminar flow range with Reynold's number from 800-2200. H2 fractions in the H2/CO mixture vary from 0.25 to 4.0. Results show that with the increase of H 2 fraction in fuel mixture, the effects of both hydrodynamic stretch and flame stretch are increased. Interpretation on the effect of stretch on flame is provided.

关键词： Mixtures

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Study on basic coal consumption characteristics in dynamic process of 660MW ultra-supercritical coal-fired unit

Study on basic coal consumption characteristics in dynamic p...

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2019 Canadian Society for Civil engineering Annual Conference, CSCE 2019

作者： Yin, Junjie Liu, Ming Yan, Junjie Zhao, Yongliang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi China

ISBN: (纸本)9780791883747

With the spreading of intermittent renewable power, coalfired power units should cycle frequently to balance the load between power supply side and demand side. Coal consumption of coal-fired units operating in dynamic processes is influenced by many factors, including thermal system, control system, heat storage variation, etc. Therefore, it is very difficult to evaluate the energy efficiency of coal-fired units operating in dynamic processes. It is important to ascertain the basic coal consumption rate in dynamic processes, which is the basis to evaluate the operation performance of coal-fired units. In this study, an off-design calculation model of 660MW ultra-supercritical coal-fired unit is developed and validated with design parameters. The developed model can be used to predict the coal consumption rates under steady-state off-design conditions. The basic coal consumption means the coal consumption of coal-fired units with operating parameters the same as target values. To calculate the basic coal consumption rate, a load cycling process is differentiated into lots of short time periods and every period is regarded as a steady-state condition with constant load, therefore the coal consumption rates in every period are equal to that of the corresponding steady-state condition. The calculation formula of basic coal consumption rates in is derived for load cycling processes. On the basis of the off-design calculation model and assumption of idealized condition, average coal consumption rates during different processes with constant load cycling rates can be calculated and analyzed. Results show that if the initial and final loads are both settled, the basic coal consumption rate remains unchanged and is independent of load cycling rate. If the load cycling amplitude remains unchanged, the basic coal consumption rate increases as the initial load decrease. The study aims to provide benchmark values for the energy consumption analysis in actual dynamic processes,

关键词： Energy efficiency

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Experimental and kinetic study on ignition delay times of 2, 5-DMF/n-heptane blends 9

Experimental and kinetic study on ignition delay times of 2,...

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9th International Conference on Modeling and Diagnostics for Advanved Engine Systems, COMODIA 2017

作者： Hu, Erjiang Gao, Zhenhua Ku, Jinfeng Meng, Xin Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Ignition delay times of 2, 5-dimethylfuran(2, 5-DMF)/n-heptane/oxygen/argon mixtures were measured in this study. Experiments were performed at the stoichiometric mixtures in the temperature range of 1200-1800K. A blend model for 2, 5-DMF/n-heptane blends was developed by combining two selected models for each individual fuel component. According to the combined model, the ignition delay time increases with an increase in the 2, 5-DMF addition level, non-linearly. Kinetic analysis was conducted to investigate interaction effects between two fuels. At relatively low blending ratios of 2, 5-DMF, the two fuels have negligible impacts on the reaction path of each other. As the 2, 5-DMF addition increases to relatively higher levels, decomposition path of n-heptane is significantly changed due to the competition for small radical. Copyright © 2017 by the Japan Society of Mechanical Engineers.

关键词： Heptane

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EXPERIMENTAL INVESTIGATION ON THE TRANSCRITICAL DYNAMIC CHARACTERISTICS OF WATER WALL FOR A SUPERCRITICAL CFB BOILER

EXPERIMENTAL INVESTIGATION ON THE TRANSCRITICAL DYNAMIC CHAR...

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ASME 2024 International Mechanical engineering Congress and Exposition, IMECE 2024

作者： Yang, Dong An, Ning Du, Xiaocheng Han, Lei Guo, Zerui Wei, Ziyu State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an China

ISBN: (纸本)9780791888667

When the boiler load varies, the operational parameters in the water wall will change, this process is called as dynamic process. Dynamic process presents unique flow and heat transfer phenomena within the water wall. To investigate the process, the research was conducted in a vertical upward smooth tube for a supercritical circulating fluidized bed (CFB) boiler. Experiments were conducted to explore the dynamic characteristics during transcritical pressure process. The results indicate that as system pressure decreases from 23 MPa to 21 MPa, the mass flux within the tube increases sharply, and the outlet fluid temperature decreases. Concurrently, a rapid rise in wall temperature was observed. As the inlet mass flux increases, the wall temperature eventually returns to the normal value. The dynamic heat transfer coefficients were calculated throughout the transcritical pressure process, revealing stages of heat transfer deterioration, subcooled boiling, and single-phase water heat transfer. In addition, experiments and numerical simulations were carried out to explore the dynamic characteristics at supercritical pressure. The dynamic response curves during the step process of heat flux and inlet enthalpy under supercritical pressure conditions were obtained. As the inlet enthalpy decreases, the system mass flux increases, and as the heat flux increases, the system mass flux decreases. And there is no rise in wall temperature during the dynamic response at supercritical pressure. Copyright © 2024 by ASME.

关键词： Water tube boilers

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Thermal-diffusive instabilities of laminar premixed CH4/H2/air flat flames 10

Thermal-diffusive instabilities of laminar premixed CH4/H2/a...

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10th Asia-Pacific Conference on Combustion, ASPACC 2015

作者： Jin, Wu Wang, Jinhua Yu, Senbin Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

As one of the most promising clean alternative fuels, natural gas has been widely used in automobile engines. However, due to the slow burning velocity of natural gas and its poor lean-burn ability, hydrogen is often added to improve its combustion behavior. Researches on the fundamental laminar premixed flame characteristics of CH4/H2 blends are of great significance to understand the combustion process in practical combustors. The intrinsic instability of laminar flame is one of the classic issues in flame dynamics, which presents the dynamic response of laminar premixed flamelets to weak perturbations. By studying dynamic mechanism of intrinsic instability, we can estimate the burning velocity more accurately and gain a deeper insight into the turbulent combustion process in spark ignition engines. In this study, the cellular instabilities of laminar premixed CH4/H2/air flat flames were studied using McKenna burner with OH-PLIF technique. It was found that the addition of H2 can broaden the lean combustion limit on flat flame burner with which the cellular instabilities were brought. The digital and OH-PLIF images were obtained to calculate the quantitative parameters of cellular length scale, which is associated with the properties of fuel mixtures such as Lewis number, Markstein number et al. Through the theoretic analysis, we make a thorough investigation on the mechanism about how the cellular scales were determined.

关键词： Natural gas

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Angle Scattering Method for Soot Concentration Measurement under Ultra-Low Emissions Condition

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Energy engineering 2022年第2期119卷 511-522页

作者： Bin Yang Xingchen Zhu Jie Deng Xiaoxu Guo Jinke Han Xiaowei Liu School of Energy and Power Engineering Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power EngineeringUniversity of Shanghai for Science and TechnologyShanghai200093China State Key Laboratory of Coal Combustion Huazhong University of Science and TechnologyWuhan430074China

Aiming at the problem of soot concentration measurement under ultra-low emission conditions,a forward small angle soot concentration measurement method is *** a typical boiler emission of 0.1μm-3.0μm bimodal distribution soot as an object,the particle scatter simulation calculation under different parameters is carried out,and the influence of detection angle and particle size on the angular scatteringmeasurement of ultra-low emission soot is *** influence of detection angle and particle size on the angular scatteringmeasurement of ultra-lowemission soot is ***,thewavelength of incident light is 650 nm,and the forward detection angle parameter is 15◦for the design of forward small angle soot concentration measurement *** experimental system for measuring soot with standard concentration is *** of particle concentration measurement of 1.0μm and 3.0μm under ultra-low emission conditions are carried *** results show that the average deviation of soot concentration measurement is less than 0.10 mg/m3 under the condition of ultra-low emission by using 15◦of forward detection,which provides an effective way for monitoring ultra-low emission soot concentration in coal-fired power plants.

关键词： Emission monitoring ultra-low emission soot concentration angular scattering

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Numerical Stability and Accuracy of Contact Angle Schemes in Pseudopotential Lattice Boltzmann Model for Simulating Static Wetting and Dynamic Wetting

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Computer Modeling in engineering & Sciences 2023年第10期137卷 299-318页

作者： Dongmin Wang Gaoshuai Lin Key Laboratory of Multiphase Flow and Heat Transfer in Shanghai Power Engineering School of Energy and Power EngineeringUniversity of Shanghai for Science and TechnologyShanghai200093China Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application Suzhou University of Science and TechnologySuzhou215009China

There are five most widely used contact angle schemes in the pseudopotential lattice Boltzmann(LB)model for simulating the wetting phenomenon:The pseudopotential-based scheme(PB scheme),the improved virtualdensity scheme(IVD scheme),the modified pseudopotential-based scheme with a ghost fluid layer constructed by using the fluid layer density above the wall(MPB-C scheme),the modified pseudopotential-based scheme with a ghost fluid layer constructed by using the weighted average density of surrounding fluid nodes(MPB-W scheme)and the geometric formulation scheme(GF scheme).But the numerical stability and accuracy of the schemes for wetting simulation remain unclear in the *** this paper,the numerical stability and accuracy of these schemes are clarified for the first time,by applying the five widely used contact angle schemes to simulate a two-dimensional(2D)sessile droplet on wall and capillary imbibition in a 2D channel as the examples of static wetting and dynamic wetting simulations respectively.(i)It is shown that the simulated contact angles by the GF scheme are consistent at different density ratios for the same prescribed contact angle,but the simulated contact angles by the PB scheme,IVD scheme,MPB-C scheme and MPB-W scheme change with density ratios for the same fluid-solid interaction *** PB scheme is found to be the most unstable scheme for simulating static wetting at increased density ratios.(ii)Although the spurious velocity increases with the increased liquid/vapor density ratio for all the contact angle schemes,the magnitude of the spurious velocity in the PB scheme,IVD scheme and GF scheme are smaller than that in the MPB-C scheme and MPB-W scheme.(iii)The fluid density variation near the wall in the PB scheme is the most significant,and the variation can be diminished in the IVD scheme,MPB-C scheme *** variation totally disappeared in the GF scheme.(iv)For the simulation of capillary imbibition,the MPB-C scheme,MPB-Wschem

关键词： Pseudopotential lattice Boltzmann model contact angle scheme static wetting dynamic wetting capillary imbibition

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Numerical analysis of the static performance of an annular aerostatic gas thrust bearing applied in the cryogenic turbo-expander of the EAST subsystem

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Plasma Science and Technology 2017年第2期19卷 115-122页

作者： Tianwei LAI Bao FU Shuangtao CHEN Qiyong ZHANG Yu HOU State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇an 710049 People＇s Republic of China Institute of Plasma Physics Chinese Academy of Sciences Hefei 230031 People＇s Republic of China

The EAST superconducting tokamak, an advanced steady-state plasma physics experimental device, has been built at the Institute of Plasma Physics, Chinese Academy of Sciences. All the toroidal field magnets and poloidal field magnets, made of NbTi/Cu cable-in-conduit conductor, are cooled with forced flow supercritical helium at 3.8 K. The cryogenic system of EAST consists of a 2 kW/4 K helium refrigerator and a helium distribution system for the cooling of coils, structures, thermal shields, bus-lines, etc. The high-speed turbo-expander is an important refrigerating component of the EAST cryogenic system. In the turbo-expander, the axial supporting technology is critical for the smooth operation of the rotor bearing system. In this paper, hydrostatic thrust bearings are designed based on the axial load of the turbo-expander. Thereafter, a computational fluid dynamics-based numerical model of the aerostatic thrust bearing is set up to evaluate the bearing performance. Tilting effect on the pressure distribution and bearing load is analyzed for the thrust beating. Bearing load and stiffness are compared with different static supply pressures. The net force from the thrust bearings can be calculated for different combinations of bearing clearance and supply pressure.

关键词： EAST helium cryogenic system aerostatic thrust beating inclination bearing load

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Corrigendum to “Numerical simulation of an externally heated fixed bed reactor for coal pyrolysis based on porous media” [Chem. Eng. Res. Des. 211 (2024) 137–151]

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Chemical engineering Research and Design 2025年 218卷 454-454页

作者： Haoyue Li Yuanpei Luo Fei Dai Jun Sui Hongguang Jin Laboratory of Distributed Energy Systems and Renewable Energy Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

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