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ASME 2000 International Mechanical engineering Congress and Exposition, IMECE 2000

作者： Guo, Lie-Jin Feng, Zi-Ping Xi'an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Province Xi'an710049 China

ISBN: (纸本)9780791826621

In the present paper the experiments for subcooled water flow and steam-water two-phase flow were conducted to investigate the effects of pulsation upon transient heat transfer characteristics in a closed-circulation helical-coiled tube steam generator. The non-uniform property of local heat transfer with steady flow was also examined. The secondary flow mechanism and the effect of interaction between the flow oscillation and secondary flow were analyzed cm the basis of the experimental data. Some new phenomena were observed and explained. A series of correlations were proposed for the average and local heat transfer coefficients both under steady and oscillatory flow conditions. The results showed that there were considerable variations in local and peripherally time-averaged Nusselt numbers for pulsating flow in a wide range of parameters. Systematic investigations of pressure drop type oscillations and their thresholds for steam-water two-phase flow in a uniformly heated helical tube were also reported. Copyright © 2000 by ASME

关键词： Drops

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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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1.t 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 1.0 microns show that the friction factors are in good agreement with the conventional predictions. The friction factors in stainless-steel tubes with diameters from 1.9 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 1. 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 50-1.70 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 373-1.70 microns with uniform heat flux do not accord with th

关键词： Glass

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Remote open-path laser-induced breakdown spectroscopy for the analysis of manganese in steel samples at high temperature

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Plasma Science and Technology 2019年第3期21卷 52-59页

作者： Minchao CUI Yoshihiro DEGUCHI Zhenzhen WANG Seiya TANAKA Min-Gyu JEON Yuki FUJITA Shengdun ZHAO School of Mechanical Engineering Xi'an Jiaotong University Graduate School of Advanced Technology and Science University of Tokushima State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Division of Mechanical Engineering Korea Maritime and Ocean University School of Mechanical Engineering Xi’an Jiaotong University

A remote open-path laser-induced breakdown spectroscopy(LIBS) system was designed and studied in the present work for the purpose of combining the LIBS technique with the steel production line. In this system, the relatively simple configuration and optics were employed to measure the steel samples at a remote distance and a hot sample temperature. The system has obtained a robustness for the deviation of the sample position because of the open-path and alloptical structure. The measurement was carried out at different sample temperatures by placing the samples in a muffle furnace with a window in the front door. The results show that the intensity of the spectral lines increased as the sample temperature increased. The influence of the sample temperature on the quantitative analysis of manganese in the steel samples was investigated by measuring ten standard steel samples at different temperatures. Three samples were selected as the test sample for the simulation measurement. The results show that, at the sample temperature of 500 ℃, the average relative error of prediction is 3.1. and the average relative standard deviation is 7.7%, respectively.

关键词： remote open-path LIBS steel manganese sample temperature quantitative analysis

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Multi-objective optimization research of open and closed air brayton cycle

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International Journal of Advanced Nuclear Reactor Design and Technology 2024年第1期6卷 21-31页

作者： Song, Meihui Qian, Yiran Leng, Yuyang Liu, Tao Yu, Lianyun Chen, Weixiong State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an710049 China Reactor Engineering Technology Research Institute China Institute of Atomic Energy Beijing102413 China

Air Brayton cycle obtains the significant advantages of high efficiency, compact structure, easy medium requirement and so on, which is one of the most suitable choices for the mobile nuclear power conversion system. In this paper, system-component combined design method is used to establish the open and closed air Brayton cycle of diverse configurations. Based on performance and compactness targets, the multi-objective optimization is carried out to find the optimal design by nondominated sorting genetic algorithm II and entropy weight method. According to the analysis, the closed intercooling reheating recuperating cycle is the configuration with the best comprehensive performance, with cycle efficiency of 33.58 %, power density of 1.5.39 kW m−3 and power mass ratio of 68.60 kW t−1. The open simple recuperating cycle is the configuration with the smallest volume and mass, with cycle efficiency of 20.01.%, system volume of 6.56 m3 and system mass of 1..98 t. The closed intercooling recuperating cycle is the most balanced configuration, with cycle efficiency of 31.33 %, volume of 9.06 m3 and system mass of 24.97 t. Based on the optimal results, off-design performance analysis of different environmental conditions is also carried out for the configurations above. © 2024 Xi'an Jiaotong University

关键词： Brayton cycle

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Application-oriented hydrolysis reaction system of solid-state hydrogen storage materials for high energy density target:A review

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Journal of Energy Chemistry 2022年第11期31卷 218-238,I0007页

作者： Jing Yao Zhen Wu Huan Wang Fusheng Yang Jianwei Ren Zaoxiao Zhang School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an 710049ShaanxiChina Department of Mechanical Engineering Science University of JohannesburgJohannesburg 2092South Africa State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049ShaanxiChina

Hydrogen storage and delivery technology is still a bottleneck in the hydrogen industry *** all kinds of hydrogen storage methods,light-weight solid-state hydrogen storage(LSHS)materials could become promising due to its intrinsic high hydrogen *** reaction of LSHS materials occurs at moderate conditions,indicating the potential for portable *** present,most of review work focuses on the improvement of material performance,especially the catalysts *** part is important,but the others,such as operation modes,are also vital to to make full use of material potential in the practical *** operation modes of hydrolysis reaction have an impact on hydrogen capacity to various *** example,hydrolysis in solution would decrease the hydrogen capacity of hydrogen generator to a low value due to the excessive water participating in the ***,application-oriented operation modes could become a {1. problem for hydrolysis reaction of LSHS *** this paper,the operation modes of hydrolysis reaction and their practical applications are mainly *** implements of each operation mode are discussed and compared in detail to determine the suitable one for practical applications with the requirement of high energy *** current challenges and future directions are also discussed.

关键词： Solid-state hydrogen storage High energy density Hydrogen generator Hydrolysis reaction Portable applications

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A new model of selective photothermolysis to aid laser treatment of port wine stains

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Chinese Science Bulletin 2013年第3期58卷 416-426页

作者： LI Dong HE YaLing WANG GuoXiang WANG YongXian YING ZhaoXia State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Department of Mechanical Engineering The University of AkronAkron 44325-3903USA Department of Dermatology Medical School of Xi'an Jiaotong University

Pulsed dye lasers equipped with cryogen spray cooling(CSC) are now widely used to treat vascular malformation such as port wine stains(PWSs).This paper presents a new integrated model that can quantitatively simulate the cooling of the skin and the heating of the targeted blood vessels in PWSs during laser *** new model is based on the classical homogeneous multi-layer skin model that treats PWS-containing dermis as a mixture of dermal tissue and homogeneously distributed *** propagation in skin and PWSs is simulated by a Monte-Carlo method,which provides accurate description of the light scattering and absorption in the *** response of a targeted vessel in the new model is then obtained from the thermal analysis of a Krogh-unit that consists of the vessel and the surrounding dermal tissues and is buried in *** results from the multi-layer skin model provide appropriate laser influence input as well as the initial thermal condition for the micro-model of the Krogh-unit.A general dynamic relation is also introduced on the surface of skin to quantify the convective cooling of *** model is then applied to dye-laser treatment(wavelength of 585 nm) of PWSs with *** results demonstrate that the present model is able to quantify thermal response of a deeply buried blood vessel in PWSs as a discrete blood vessel does,with a more realistically estimate of the sheltering effect of the dermal tissue(scattering) and blood vessels(absorption) in front of the targeted *** understand the poor response of PWSs in clinic,the thermal characteristics of a targeted vessel was simulated under various *** effects of two morphological parameters,the vessel diameter and the burying depth of the vessel,are then systematically investigated under various pulse durations and fluences of laser.A threshold fluence for given vessel diameter and depth is then estimated quantitatively under the condition of the optimal laser pulse durat

关键词：激光治疗仪 Monte-Carlo方法鲜红斑痣脉冲持续时间激光能量密度热作用皮肤组织集成模型

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Experimental study on air-staged combustion in a W-shaped boiler furnace 9

Experimental study on air-staged combustion in a W-shaped bo...

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9th International Conference on power {1., ICOPE 2009

作者： Liu, Ruwei Zhou, Qulan Hui, Shien Zhao, Qinxin Fan, Qingwei Xu, Tongmo Yu, Zhanying State Key Laboratory of Power Engineering Multiphase Flow Department of Energy and Power Engineering Xi'an Jiaotong University Xi'an Shaan xi710049 China

The experimental study was carried out on the air-staged combustion of different coal in a 1.MW W-shaped furnace. The combustion process occurred in two zones: the pre-stage combustion zone and the primary combustion zone. A variable SR was introduced to represent the air stoichiometric ratio in the pre-stage combustion zone. It is found that as SR decreases in the test range, the flame penetration depth is lengthened, and the temperature at the exit of the furnace decreases. Meanwhile, the maximum temperature in the central of the furnace first increases and then decreases, whereas the combustible loss and nitrogen oxides (NOx) emissions first decrease and then increase. The value of SR corresponding to the optimal combustion performance is 0.67 for lean coal and 0.65 for anthracite. Besides, it is also indicated that the effects of air-staging method are more significant on the lean coal than that on the anthracite.

关键词： Furnaces

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Function-reversible facets enabling SrTiO_(3)nanocrystals for improved photocatalytic hydrogen evolution

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Frontiers in Energy 2024年第1期18卷 101-109页

作者： Bin WANG Bei AN Xiaoqian LI Shaohua SHEN School of Physics Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter(Ministry of Education)Key Laboratory of Shaanxi for Advanced Materials and Mesoscopic PhysicsXi’an Jiaotong UniversityXi’an 710049China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049China

It has been widely reported that,for faceted nanocrystals,the two adjacent facets with different band levels contribute to promoted charge separation,and provide active sites for photocatalytic reduction and oxidation reaction,*** such cases,only one family of facets can be used for photocatalytic hydrogen ***,by using SrTiO_(3)nanocrystals enclosed by{023}and{001.facets as a model photocatalyst,this paper proposed a strategy to achieve the full-facets-utilization of the nanocrystals for photocatalytic hydrogen via chemically depositing Pt nanoparticles on all *** photo-deposition experiment of CdS provided direct evidence to demonstrate that the{023}facets which were responsible for photooxidation reaction can be function-reversed for photocatalytic hydrogen evolution after depositing Pt nanoparticles,together with the{001.***,the full-facets-utilization led to a much-improved activity for photocatalytic hydrogen,in contrast to those SrTiO_(3)nanocrystals with only{001.facets deposited by Pt nanoparticles via a photo-deposition method.

关键词： SrTiO_(3)nanocrystals crystal facets photocatalysis hydrogen evolution

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Nanoparticle-induced drag reduction for polyacrylamide in turbulent flow with high Reynolds numbers

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Chinese Journal of Chemical engineering 2023年第4期56卷 290-298页

作者： Xiaoping Li Jiaxin Pan Jinwen Shi Yanlin Chai Songwei Hu Qiaorong Han Yanming Zhang Xianwen Li Dengwei Jing State Key Laboratory of Multiphase Flow in Power Engineering&International Research Center for Renewable Energy Xi'an Jiaotong UniversityXi'an 710049China Oil and Gas Technology Research Institute of Petrochina Changqing Oilfield Company Xi'an 710018China

Although having been increasingly studied, there is still controversy as to when the addition of nanoparticles could improve the drag reduction performance of polymer drag reducer and particularly what is the underlying mechanism from the fluid dynamics viewpoint. The drag reduction effects of adding SiO_(2) nanoparticles to various polymer polyacrylamide(PAM) solutions were examined in this *** optimal combination of SiO_(2) nanoparticles with cationic polyacrylamide was ***,the addition of SiO_(2) nanoparticles to cationic polyacrylamide solution was shown to be quite efficient for reducing drag, but only at higher flow rates with Reynolds numbers more than 6000, below which the nanoparticle addition is even negative. The addition of SiO_(2) nanoparticles to the PAM solution is supposed to play a dual role. The first is an increase in flow resistance caused by the Brownian motion of nanoparticles, while the second is a decrease in flow resistance caused by acting as nodes to protect the polymer chain from shear-induced breaking under high shear action. At optimal nanoparticle concentration and under higher Reynolds numbers, the later effect is dominant, which could improve the drag reduction performance of polymer drag reducers. Our work should serve as a guide for the application of natural gas fracturing, where the flow rate is frequently very high.

关键词： Drag reduction SiO_(2)nanoparticle Cationic polymer Brownian motion

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Comparison of hydrogen generation rate between cora-1. test and MELCOR simulation: Clad solid-phase oxidation models using self-developed code MYCOAC

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Nuclear Technology 2015年第1期192卷 25-34页

作者： Wang, Jun Corradini, Michael L. Haskin, Troy Zhang, Yapei Lu, Qing Tian, Wenxi Su, Guanghui Qiu, Suizheng Xi'an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an710049 China University of Wisconsin-Madison College of Engineering MadisonWI53706 United States Nuclear Power Institute of China Chengdu610041 China

To better understand the MELCOR oxidation and degradation models, past work compared the MELCOR model to a CORA experiment (CORA Test 1.). These MELCOR analyses specifically focused on fuel bundle heatup and clad oxidation when compared to CORA test data. The comparison allowed the authors to investigate differences between hydrogen generation data and simulation results. Several potential reasons were considered for hydrogen generation rate differences, including MELCOR input power, heat transfer modeling, the clad solid-phase oxidation model, and the gaseous steam diffusion model. This work focuses on the possible uncertainty in the clad oxidation models used in MELCOR. First, the MELCOR nodalization approach for the CORA test was reviewed. Then, the temperature history and spatial variation were examined. One main focus was to consider other clad solid-phase oxidation models to compare the MELCOR models. This was accomplished by developing a separate model, MYCOAC, using MELCOR temperature predictions as input. Finally, the mass transfer resistance of steam diffusion to the clad surface was examined and found to be a small effect. While the Baker-Just solid-phase oxidation model showed better agreement with CORA data at low temperatures, the conclusion in this paper is that the oxidation models are not the major source of uncertainty in hydrogen generation rate differences. Future work will focus on heat transfer modeling of the CORA test.

关键词： Diffusion

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