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Transient Evaporation Simulation of the Forced Circulation Hot Water Boiler

IOP Conference Series: Materials Science and engineering 2020年第1期721卷

作者： Junjie Bao Di Wang Feng Liu Zhiguo Qu Hongtao Xu Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai 200093 China Shanghai Institute of Special Equipment Inspection and Technical Research Shanghai 200062 China China Special Equipment Inspection and Research Institute Beijing 10013 China Moe Key Laboratory of Thermo-Fluid Science and Engineering Xi'an Jiaotong University Xi'an 710049 China

This paper presents a comprehensive analysis of the water vaporization in a hot water boiler system. The Computational Fluid Dynamics (CFD) technology was adopted to simulate the transient water evaporation in the boiler termed as DZL14-1.25/115/70-AⅡ under the assumption of extreme conditions such as the water pump failure. The results indicated that the average pressure in the pipeline increased from 0.57Mpa to 0.66Mpa (the setting pressure of the safety valve) within 1050s. The pressure increased rapidly with the time increase. The average temperature of hot water changed linearly with time, and the internal thermal deviation of the hot water pipeline in the boiler decreased with time. The internal vaporization phenomenon of the hot water boiler became significant under the extreme condition. The steam flowed upward and accumulated in the upper part of the boiler shell. At 1050s, the vapor volume fraction in the hot boiler was 1.05%, which indicated that the safety valve above the stream shell need to be opened in time after 1050s to ensure the safety of the boiler.

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A mesh mapping method for MCNP and fluent coupling simulation

A mesh mapping method for MCNP and fluent coupling simulatio...

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2017 Transactions of the American Nuclear Society, ANS 2017

作者： Wang, Xinan Zhang, Dalin Wang, Mingjun Tian, Wenxi Qiu, Suizheng Su, Guanghui State Key Laboratory of Multiphase Flow in Power Engineering School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an710049 China

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Kinetics of hydrogen abstraction and addition reactions of 3-hexene by H radical

Kinetics of hydrogen abstraction and addition reactions of 3...

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11th Asia-Pacific Conference on Combustion, ASPACC 2017

作者： Yang, Feiyu Sun, Wuchuan Pan, Youshun Deng, Fuquan Jiang, Xue Zhang, Yingjia Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xianning West Road Xi’anShaanxi710049 China

Rate coefficients of H-atom abstraction and addition reactions of 3-hexene by the hydroxyl radical (H) were determined using canonical variational transition-state theory, with potential energy surface evaluated at the CCSD/CBS//BHandHLYP/6311G (d, p) level and quantum mechanical effect corrected by the multi-dimensional small-curvature tunneling method. Results reveal that accounting for approximate 70% of the overall H-atom abstractions occur in the allylic site via both direct and indirect channels. The indirect channel containing two Van der Waals pre-reactive complexes exhibits two times higher rate coefficient relative to the direct one. The H-addition reaction also contains two Van der Waals complexes, and its submerged barrier results in a negative temperature coefficient behavior at low temperatures. In contrast, the H-addition pathway dominates only at the temperatures below 590 K whereas the H-atom abstraction reactions dominate overwhelmingly at the temperature over 590 K. All of the rate coefficients calculated with an uncertainty of a factor of 5 were estimated. Analyses on the potential energy surface and minimum reaction path were also performed in this study. © 2018 Combustion Institute. All Rights Reserved.

关键词： Addition reactions

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Theoretical investigation on heat-electricity decoupling technology of low-pressure steam turbine renovation for CHPs

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IOP Conference Series: Earth and Environmental Science 2019年第4期227卷

作者： Qingbo Hu Kun Wang Li Zhang Liansheng Zhou Rong Chen Shan Wang Yu Zhang Guohao Li Tianjin Electric Power Science & Research Institute Tianjin 300384 State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiao Tong University Xi'an 710049.

The power grid peaking capacity is insufficient due to the increasing installed capacity of renewable power. Moreover, it is also restricted by the operation mode of combined heat and power units (CHPs), the minimum electricity loads of which are determined by the heat load. It is significant to study the heat-electricity decoupling technologies for CHPs. Therefore, the low-pressure steam turbine renovation technology is studied in this paper with a 300MW unit as reference case. Results show that the minimum electric load rate and the coal consumption are decreased, and the heat-electricity ratio is increased significantly for CHP with low-pressure steam turbine renovation. When the heat load is 1200 GJ/h, the minimum electric load rate and coal consumption with low-pressure steam turbine renovation can be reduced by 32.4 and 30.9 % respectively. The heat-electricity ratio can be increased by 68.8 % after renovation of low-pressure steam turbine.

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Flame front evolution and self-acceleration of hydrogen spherically expending flames 11

Flame front evolution and self-acceleration of hydrogen sphe...

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11th Asia-Pacific Conference on Combustion, ASPACC 2017

作者： Cai, Xiao Wang, Jinhua Zhao, Haoran Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University NO.28 Xianning West Road Xi’an710049 China

An experimental study on flame front evolution and self-acceleration of hydrogen spherically expending flames was conducted on a constant volume combustion chamber over a wide range of Lewis number at elevated pressures. Flame morphology, onset of flame acceleration and flame self-similar acceleration were analyzed. The results shows that the critical radius for onset of flame acceleration increases with the increase in effective Lewis number and the decrease in initial pressure. And the critical Peclet number increases nonlinearly with the increasing Markstein length. Thus, the onset of flame acceleration is controlled by the couple effects of hydrodynamic and diffusional-thermal instabilities. Furthermore, the self-similar acceleration exponent increases with the decrease in the effective Lewis number (or Markstein number) and almost keeps constant with initial pressure. It is concluded that the self-similar acceleration exponent is mainly affected by diffusional-thermal instability. © 2018 Combustion Institute. All Rights Reserved.

关键词： Acceleration

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Experimental study of n-decane decomposition with microsecond pulsed discharge plasma

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Plasma Science and Technology 2017年第12期19卷 89-95页

作者：宋飞龙金迪贾敏魏雯雯宋慧敏吴云 Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi'an 710038People's Republic of China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049People's Republic of China Science and Technology on Plasma Dynamics Laboratory Xi'an Jiaotong UniversityXi'an 710049People's Republic of China

A highly-integrated experimental system for the plasma decomposition of fuels was *** were conducted in a flow reactor at atmospheric pressure and confirmed that n-decane could be cracked by large-gap dielectric barrier discharge under the excitation of a microsecond-pulse power supply. Alkanes and olefins with a C atom number that is smaller than10 as well as hydrogen were found in the cracked products of n-decane（n-C10 H22）. The combination of preheating and plasma decomposition had strong selectivity for olefins. Under strong discharge conditions, small molecule olefins were found in the products. Moreover, there was a general tendency that small molecule olefins gradually accounted for higher percentage of products at higher temperature and discharge frequency.

关键词： plasma DBD decomposition n-decane

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Numerical Analysis of flow Instability in the Water Wall of a Supercritical CFB Boiler with Annular Furnace

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Journal of Thermal Science 2016年第4期25卷 372-379页

作者： XIE Beibei YANG Dong XIE Haiyan NIE Xin LIU Wanyu State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University

In order to expand the study on flow instability of supercritical circulating fluidized bed(CFB) boiler,a new numerical computational model considering the heat storage of the tube wall metal was presented in this *** lumped parameter method was proposed for wall temperature calculation and the single channel model was adopted for the analysis of flow *** on the time-domain method,a new numerical computational program suitable for the analysis of flow instability in the water wall of supercritical CFB boiler with annular furnace was *** verify the code,calculation results were respectively compared with data of commercial *** to the comparisons,the new code was proved to be reasonable and accurate for practical engineering application in analysis of flow *** on the new program,the flow instability of supercritical CFB boiler with annular furnace was simulated by time-domain *** 1.2 times heat load disturbance was applied on the loop,results showed that the inlet flow rate,outlet flow rate and wall temperature fluctuated with time eventually remained at constant values,suggesting that the hydrodynamic flow was *** results also showed that in the case of considering the heat storage,the flow in the water wall is easier to return to stable state than without considering heat storage.

关键词： supercritical CFB with annular furnace heat storage flow instability wall temperature numerical analysis

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Pressure drops and model modification for two-phase flow in porous beds with coarse particles 25

Pressure drops and model modification for two-phase flow in ...

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2017 25th International Conference on Nuclear engineering, ICONE 2017

作者： Li, Xumao Zou Liangxing Wang, Liubo Kong Huasheng State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xianning West Road 28# Xi'an city710049 China

ISBN: (纸本)9780791857823

Motivated by reducing the uncertainties in coolability analysis of a debris bed, this paper proposed a modified model for the pressure drops of two phase flow through packed beds with coarse particles based on the experimental studies. The experiments are carried out on the test facility of DEBECO-LT (DEbris BEd COolability-Low Temperature), which was designed to investigate single / two-phase flow in porous beds. The coarse particles are packed in the cylindrical test section with the inner diameter of 120 mm and the height of 600 mm. Through single-phase flow tests in homogeneous beds, the reliability of the whole experimental system is ensured. Then two-phase flow tests are performed to investigate the flow characteristics, to provide basic data for verifying and modifying the existing models. The results show that, the interfacial drag in beds with coarse particles will result in a decreasing tendency in the pressure drop curves along with the fluid velocity, and the the effect of interfacial drag should be considered in the debris coolability analysis models for beds with coarse particles. Compared with the existing models, the new model shows relatively satisfactory forecasting ability, and the predictions have favorable agreement with existing experimental data under various conditions. This modified model could be applied to calculate the pressure drops of twophase flow in coarse-particle beds. © Copyright 2017 ASME.

关键词： Pressure drop

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Experimental Research on flow Pulse Characteristics of Pressurized-Liquid-Screen Bed

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Kung Cheng Je Wu Li Hsueh Pao/Journal of engineering Thermophysics 2017年第10期38卷 2183-2189页

作者： Hu, Zheng-Tao Li, Lian Li, Na Zhou, Qu-Lan State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

The experimental monitoring system of pressurized-liquid-screen bed was designed and set in this paper. The flow characteristics were studied especially the analysis of differential pressure pulse characteristics and friction factors variation by the way of adjusting gas flow, liquid flow and operation pressure parameters. According to the analysis of comparing experiment data and theory, the variation principle of pressure pulse intensity and friction factors under different gas flow, liquid flow and operation pressure was revealed as well as the optimal operation parameter was analyzed through combining the principle of fume desulfurization gas-liquid interactive reaction. This paper provides the crucial design references to the industrial application of pressurized-liquid-screen gas-liquid reaction system. © 2017, Science Press. All right reserved.

关键词： flow of gases

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Effects of inertia on the deformation of drops enclosed by elastic interfaces in linear shear flow

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Kexue Tongbao/Chinese Science Bulletin 2017年第16期62卷 1682-1690页

作者： Luo, Zhengyuan Bai, Bofeng State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Droplets enclosed by elastic interfaces can be extensively found in nature and engineering applications. For instance, oil-water droplets in petroleum engineering can be surrounded by Asphaltene thin film;biological cells are usually surrounded by elastic biological membranes consisting of lipid bilayers with spectrin proteins;droplets enclosed by polymer membranes or lipid bilayers are also widely found in materials science and engineering. This type of droplets is also an excellent structure for encapsulation, transport and release of active agents due to the presence of elastic interface, thus they are widely used in applications such as cosmetics and drug delivery. To study the deformation behavior of single droplet enclosed by complex interfaces under shear flow is fundamental for understanding rheological characteristics of droplet suspensions and for developing droplet-based substance transport technologies. The presence of various molecules confers the drop interfaces various special mechanical properties, such as resistances to shear deformation, area dilatation and bending deformation. Those special mechanical properties significantly influence the transport characteristics of momentum and energy between droplets and surrounding fluids, thus conventional theories based on surface tension are no longer valid for understanding the dynamics of droplets enclosed by elastic interfaces. Generally, the deformation of droplets enclosed by elastic interfaces under shear flow is mainly governed by the coupling of fluid inertia, interface elasticity and fluid viscosity. Current literatures mostly focus on the deformation of drops with elastic interfaces with inertia neglected, which is based on the assumption of Stokes flow. However, the effects of fluid inertia are of great importance in many cutting edge technologies and in vivo bioprocesses, such as inertial microfluidic technologies for separation and manipulation of droplets, blood flow with moderate Reynolds nu

关键词： Numerical models

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