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An experimental study of premixed laminar methane/oxygen/argon flames doped with hydrogen at low pressure with synchrotron photoionization

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Chinese Science Bulletin 2008年第8期53卷 1262-1269页

作者： WANG JinHua HU ErJiana HUANG ZuoHua MA ZhiHao TIAN ZhenYu WANG Jina LI YuYana State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei 230029 China

Laminar premixed stoichiometric methane/hydrogen/oxygen/argon flames were investigated with tun- able synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam sampling mass spec- trometry techniques. The methane/hydrogen fuel blends with hydrogen volumetric fraction of 0, 20%, 40%, 60% and 80% were studied. All observed flame species, including stable intermediates and radi- cals in the flames, were detected by measuring photoionization mass spectra and photoionization effi- ciency (PIE) spectra. Mole fraction profiles of major species and intermediates were derived by scan- ning burner at some selected photon energies near ionization thresholds. The influence of hydrogen addition on mole fraction of major species and intermediates was analyzed. The results show that the major species mole fraction of CO, CO2 and CH4 decreases with the increase of hydrogen fraction. The mole fraction of intermediates measured in this experiment decreases remarkably with the increase of hydrogen fraction. This would be due to the increase of H and OH radicals by hydrogen addition and the high diffusivity and activity of H radical promoting the chemical reaction. In addition, the increase of H/C ratio with the increase of hydrogen fraction also leads to the decrease of the mole fraction of car- bon-related intermediates and contributes to the decrease of unburned and incomplete combustion products.

关键词：甲烷氢混合火焰同步加速器 MBMS

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Simulation of supercritical water gasification of organic wastes with neural network model

Simulation of supercritical water gasification of organic wa...

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17th World Hydrogen Energy Conference 2008, WHEC 2008

作者： Zhang, Qinming Wang, Shuzhong Chen, Chongming Gong, Yanmeng Xu, Donghai State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

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No new physics in single-phase fluid flow and heat transfer in mini-and micro-channels-is it a conclusion?

No new physics in single-phase fluid flow and heat transfer ...

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1st ASME Micro/Nanoscale Heat Transfer International Conference, MNHT08

作者： Wen-Quan, Tao Gui-Hua, Tang Ya-Ling, He Zhuo, Li State Key Laboratory of Multiphase Flow School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 China

ISBN: (纸本)0791842924

First the flow friction characteristics of nitrogen and helium in stainless steel microtubes, glass microtubes, square glass microchannels, and rectangular silicon microchannels are tested. The data in glass microtubes with diameters from 50 to 201 microns and in square glass channels with characteristic diameters from 52 to 100 microns show that the friction factors are in good agreement with the conventional predictions. The friction factors in stainless-steel tubes with diameters from 119 to 300 microns are much higher than the conventional ones. The results for two of the four silicon microchannels with characteristic diameters from 26-60 microns are in good agreement while those of the other two channels are larger. This discrepancy is resulted from the large relative surface roughness. Smaller friction factors in glass microtubes with diameters from 10 to 20 microns are obtained due to the rarefaction effect. Second the flow friction experimental data for deionized water flow in glass microtubes with diameters from 50 to 530 microns show that friction factors and transition Reynolds numbers are in good agreement with the conventional predictions. However, the friction factors in stainless steel microtubes with diameters from 50-1570 microns are much higher than the conventional predictions. This discrepancy is attributed to the large surface relative roughness or denser roughness distribution. Numerical simulations considering electroviscous effect are carried out. The simulation results show that the electroviscous effect does not play a significant role in the friction factor for channel dimensions of the order of microns though it does affect the velocity profile and hence it could be neglected in engineering applications for channel dimensions of the order of microns. Third the measured local Nusselt number distribution of deionized water along the axial direction of the stainless steel tubes of 373-1570 microns with uniform heat flux do not accord with th

关键词： Glass

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EXPERIMENTAL STUDY ON GAS-LIQUID TWO-PHASE flowS IN AN AREATION TANK BY USING IMAGE TREATMENT METHOD

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Journal of Hydrodynamics 2008年第5期20卷 650-655页

作者： CHENG Wen LIU Wen-hong HU Bao-wei WAN Tian State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇an 710049 China Environment Research Institute Xi＇an University of Technology Xi＇an 710048 China Environment Research Institute Xi＇an University of Technology Xi＇an 710048 China

Particle Image Velocimetry （PIV） technique was employed to study experimentally gas-liquid two-phase flow in an aeration tank. In terms of the PIV principles, an algorithm of PIV based on the Fast Fourier Transformation （FFT） was worked out. The PIV program was developed and verified, and then was used to measure three kinds of states in the testing device. The program was also used to calculate and analyze the related parameters. The experimental data indicate that the bubbles in testing device have the longest resident time and stronger turbulent intensity for the gas-liquid two-phase flow in a special case （Case 3）, resulting in great increase of the oxygen transferring speed and efficiency, whereby providing the basis for the selection design of aeration tank.

关键词： gas-liquid two-phase flow Particle Image Velocimetry （PIV） Fast Fourier Transformation （FFT） aeration tank

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Combustion research in internal combustion engines and its challenges

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Neiranji Xuebao/Transactions of CSICE (Chinese Society for Internal Combustion Engines) 2008年第SUPPL.期26卷 101-106页

作者： Huang, Zuo-Hua Jiang, De-Ming Wang, Xi-Bin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

In this paper, the statues and development trends of combustion research in internal combustion engines are discussed from several aspects. Some key issues in combustion of internal combustion engines are raised. The combustion in internal combustion engines is a complex process with chemical reaction and energy conversion and there are still many aspects needed to be clarified, especially the chemical reaction mechanism and soot formation. Meanwhile, combustion diagnostic is playing an increasing role in the understanding of combustion. The motivation to deepen the research is the continuous requirement of high-efficiency and low-emission engines. Remarkable progress has been achieved in developing low-emission combustion concept like HCCI and low-temperature combustion. Alternative fuel engines become an important aspect in engine research and development. Advanced combustion technology combined with fuel control technology and after-treatment can realize the high-efficient and low-emission target.

关键词： Internal combustion engines

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Preparation and characterization of ZnO/ZnS hybrid photocatalysts via microwave-hydrothermal method

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Frontiers of Environmental Science & Engineering 2008年第4期2卷 415-420页

作者： Jinglian ZHAO Liang ZHAO Xinping WANG State Key Laboratory of Multiphase Flow in Power Engineering Department of Environmental EngineeringXi’an Jiaotong UniversityXi’an 710049China Department of Physics and Astronomy Rice UniversityHoustonTX 77005-1657USA

The photocatalytic performance of ZnO/ZnS hybrid nanocomposite was largely higher than that of the mere ZnO or ZnS nanoparticles,but the complicated procedure and misdistribution of final products limited its large-scale *** exploration of a novel synthesis route of ZnO/ZnS hybrid photocatalysts with high catalytic performance is becoming a crucial step for the large-scale application of ZnO/ZnS hybrid photocatalytic *** and characterization of nanosized ZnO/ZnS hybrid photocatalysts were studied in this *** photocatalysts were obtained via microwavehydrothermal crystallization with the help of sodium *** products were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),particle size distribution(PSD),and Fourier transformed infrared spectroscopy(FT-IR).The results indicated that so-synthesized ZnO/ZnS samples consisted of the high pure cubic(sphalerite)ZnS and hexagonal ZnO nanocrystallines with a narrow particle size *** possible formation mechanisms of ZnO/ZnS nanocrystallines were mainly attributed to the superficially protective effect of *** photocatalytic experiments demonstrated that the ZnO/ZnS photocatalysts exhibited a higher catalytic activity for the degradation of acid fuchsine than other monocomponents.

关键词： photocatalyst ZnO/ZnS sodium citrate hydrothermal microwave

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Research on holographic interference pattern of laser holographic interferometric technique

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Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument 2008年第SUPPL. 2期29卷 438-442页

作者： Guo, Ying He, Maogang Zhong, Qiu Zhang, Ying State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

The processing of interference fringe is the most important step in holographic interferometric technique. The interference fringe of mass diffusion were gathered and proposed, and 3 key steps in the process which reduce the precision mostly were improved in this paper. The improvements include the following steps: wavelet de-noise, frequency-domain wave filtering, phase unwrapping. The categories of noise were analyzed and some specific methods were used to reduce the noise. The improvements increased the precision greatly, and established a solid foundation for the using of laser holographic interferometric technique.

关键词： Wavelet transforms

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PIV measurement of turbulent mixing layer

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Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics 2008年第11期29卷 1867-1871页

作者： Guo, Fu-De Chen, Bin Wang, Zhi-Wei Guo, Lie-Jin Zhang, Xi-Min State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

In present paper a turbulent mixing layer with the velocity ratio 4:1 which was produced by a special designed splitter plated placed in a vertical rectangular channel was experimentally investigated by PIV. The Reynolds number based on the velocity difference of two steams and hydraulic diameter of the channel ranges from 4400-158400. It is found that the scale of coherent vortex structure increases with increasing the Reynolds number and then decreases with continuously increasing the Reynolds number. The injected bubble will delay or hinder the evolution of the coherent structures. Afterwards the statistical and instantaneous distributions of Reynolds stress, turbulent intensity, vorticity and swirling strength are obtained. The results show that all these turbulent parameters exist only in a very narrow conical region in the downstream of the mixing layer. The Reynolds stress and turbulent intensity first increase and then decrease with increasing the Reynolds number and decrease with the evolution of mixing layer, while vorticity and swirling strength increase with increasing the Reynolds number and decrease with the evolution of mixing layer.

关键词： Reynolds number

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Influence of the initial condition on pool water instantaneous flash evaporation

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Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics 2008年第8期29卷 1335-1338页

作者： Guo, Ying-Li Deng, Wei Yan, Jun-Jie Wang, Gui-Fang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

An experimental study has been performed to investigate pool water instantaneous flash evaporation in a rectangle chamber. The water level was at 40 mm, 60 mm, 100 mm, 150 mm. Initial conditions of the liquid varied from 55 to 88C temperature and 3 to 35C superheat. Visualization of the phenomenon using a CCD camera lets us firstly point out the influence of the initial conditions on the flashing phenomenon. The experimental results show that at a constant initial water temperature, the greater the superheat approaches, the more quickly the liquid temperature will decrease. At a constant superheat, the initial water temperature has little influence on the decrease rate of the water temperature. The higher the water level will be, the slower the water temperature will decrease as well as the higher the water temperature will be when the flashing is finished. Experimental study allows us to correlate the water temperature with the initial water temperature and the superheat while flashing is going.

关键词： Water temperature

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Measurement of diffusion coefficient using Michelson interferometry

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Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument 2008年第SUPPL. 2期29卷 488-492页

作者： Guo, Ying He, Maogang Zhang, Ying Zhong, Qiu State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

In this paper, an experimental system for the measurement of mass diffusion coefficient using Michelson laser holographic Interferometry was designed and constructed. The experimental system include: the subsystem of Michelson interferometer, the diffusion cell for the mass diffusion of liquid-liquid, the subsystem of thermostatic water bath, the subsystem of image collecting and image processing. The mass diffusion coefficients of 0.33 molL-1 KCI solution with water at the temperature of 289.15 K were measured, and the result shows that the average of relative deviations is 1.30% compared with the literature values, and it verified the accuracy and reliability of the system. The mass diffusion coefficients of 0.1 molL-1 saccharose with water at 5 different temperature were measured, and the result shows that the biggest relative deviations is within 5% which verified the reliability of the system further.

关键词： Michelson interferometers

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