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Secondary side flow field of steam generator with coupled heat transfer from primary to secondary side fluid

Yuanzineng Kexue Jishu/Atomic Energy Science and Technology 2014年第8期48卷 1398-1405页

作者： Cong, Teng-Long Tian, Wen-Xi Qiu, Sui-Zheng Su, Guang-Hui Department of Nuclear Science and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

The 3D flow characteristics in SG can provide input for the analysis of flow induced vibration (FIV). The secondary side flow field was simulated based on the porous media model with FLUENT solver. The flow resistances of flow along and cross tubes as well as flow resistances of downcomer, support plates and separators were added to the momentum equation. The 3D heat transfer from primary to secondary side fluid was calculated during iteration and set as the energy source of secondary side fluid, and the calculation results agree well with the design values. Meanwhile, the results show that the resultant localized thermal-hydraulic characteristics were unevenly distributed. The maximum and minimum flow vapor qualities flowing into the primary separators are 0.75 and 0.07, respectively. The average heat transfer coefficients of primary and secondary sides are 1. 856.5 and 63 623.0 W/(m2·K), respectively. The maximum heat transfer coefficient of secondary side is 1.2 862.9 W/(m2·K). The average heat flux of U-tube is 1.9.9 kW/m2. The maximum cross flow velocity and cross flow energy (ρu2) through the U-bend region are 4.06 m/s and 1.1.5 J/m3, respectively.

关键词： Porous materials

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Sensitive detection of iodine by low pressure and short pulse laser-induced breakdown spectroscopy (LIBS)

Sensitive detection of iodine by low pressure and short puls...

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作者： Zhang, Xiaobo Deguchi, Yoshihiro Wang, Zhenzhen Yan, Junjie Liu, Jiping State Key Laboratory of Multiphase Flow in Power Engineering Xi'An Jiaotong University Xi'an 710049 China Graduate School of Advanced Technology and Science University of Tokushima Tokushima 770-8501 Japan

In this study, Laser-Induced Breakdown Spectroscopy (LIBS) technology was applied to detect iodine, an essential element for human body. Iodine in buffer gases of N2 and air was detected using nanosecond and picosecond breakdowns of CH3I at reduced pressure. Compared with the conventional methods of iodine measurement, LIBS technology without sample preparation shows the merits of fast response, real-time detection and enhanced detection limit. The measurement results of iodine demonstrated that low-pressure LIBS is the favourable method for trace species measurement in analytical applications. The plasma generation processes of multi-photon ionization and electron impact ionization can be controlled by pressure and laser pulse width for the larger ionization and excitation processes of iodine, which was discussed by the intensity ratio of iodine emission at 1.3 nm to nitrogen emission at 1.4.3 nm. The detection limit of iodine measurement in N2 was 60 ppb in nanosecond breakdown at 700 Pa. Iodine in air as the buffer gas was also detected using nanosecond and picosecond breakdowns to examine the effect of oxygen. This journal is © the Partner Organisations 201..

关键词： Impact ionization

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Simulation Investigation on the Dynamic Characteristics of a 600MW Supercritical Lignite-fired Pulverized Boiler

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Energy Procedia 2014年 61卷 1434-1437页

作者： Xiaoqu Han Zhaonan Xue Ming Liu Junjie Yan Jinshi Wang Daotong Chong Jiping Liu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China

The real-time dynamic simulation model of a 600MW lignite-fired pulverized boiler, which is a supercritical once-through boiler with fan mill three drying media direct fired system, was established. The step reduction of hot flue gas flow rate was simulated. The dynamic responses of live and reheat steam temperatures were obtained and analyzed. Results show that the response of steam temperature is an oscillation process. The superheat and reheat steam overtemperature values are influenced by the boiler load, the hot flue gas extracting percent and the inertia time of pulverizing system.

关键词： Simulation Dynamic Characteristics Hot Flue Gas Extracting Percent Steam Overtemperature

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Study on Steam-Water Solar Cavity Receiver

Study on Steam-Water Solar Cavity Receiver

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201.第四届国际新能源产业大会——主题：助力一个美丽、洁净、可持续发展的家园

作者： Jinjia Wei State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University

Solar energy is clean without pollution,rich and free,so solar thermal power has the huge potential for future energy *** type concentrating technology can be used for large-scale solar power *** the power tower system,the heat receiver is the key equipment for sunlightheat *** thermal performance of the receiver will affect the efficiency of the entire power *** is no rich experience on the design of receiver,which is mainly based on the coal-fired *** to the non-uniform and instantaneous characteristics of sunlight,the receiver should differ greatly from the conventional coal-fired *** it is necessary to study the receiver according to the sunlight *** experiment platform for testing the thermal performance of a water/steam cavity receiver was firstly designed and *** start-up curves under different operating pressures were obtained and the receiver has low thermal efficiency of only about 55-70%.The low thermal efficiency is attributed to the low mass flow rate.A combined method was proposed to evaluate the thermal performance of the cavity receiver for start up and *** numerical results are in good agreement with the *** results suggested that an appropriate mass flow rate of 200 kg/h should be chosen for the design and operation of the experiment *** thermal performance of a solar cavity receiver under windy conditions was numerically *** heat flux and temperature distributions on boiling tubes in the cavity were *** convective and radiative heat losses were analyzed in *** the wind flow angle or velocity can obviously affect the air velocity inside the cavity,which reaches the maximum value for side on wind,resulting in a large convective heat *** on the experimental and numerical studies,a water/steam cavity receiver was designed and *** receiver is now being used in 1.W power tower plant in China with a

关键词： Study on Steam-Water Solar Cavity Receiver

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Thermodynamic Analysis on a Pre-dried Lignite-fired power System: Comparison on Energy Supply Systems for Dryer

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Energy Procedia 2014年 61卷 1424-1427页

作者： Ming Liu Junjie Yan Jinshi Wang Daotong Chong Jiping Liu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China

Pre-drying is a potential way to improve the electric generation efficiency of lignite-fired power plant, and steam is a main kind of drying heat source. In conventional pre-dried lignite-fired power system, the steam extraction of regenerative system is led to the dryer directly. The steam extraction must be used by the dryer after throttling, if the energy mismatch exists between the supply of steam extraction and the need of dryer. Two systems of energy supply for the dryer, that the energy of the steam extraction is supplied to the dryer via compressor or ejector, were proposed in this paper to further increase the energy utilization efficiency. These systems were thermodynamic analyzed, and the electric generation efficiencies of these systems were compared. The energy saving boundary was gotten.

关键词： Thermodynamics Lignite pre-drying Compressor Ejector

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Research on the two-phase flow and separation mechanism in the oil-gas cyclone separator

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IOP Conference Series: Materials Science and engineering 2015年第1期90卷

作者： L Z Wang X Gao J M Feng X Y Peng School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049China

The cyclone separator has attracted increasing attention due to its small size, rapid construction and high separation efficiency. This study investigated its gas-liquid two-phase flow and separation characteristics experimentally and numerically. A numerical model of two- phase flow in the cyclone separator was proposed using the Euler-Lagrange method. The distribution of pressure, tangential and axial velocity in the gas-phase flow field was obtained, and the oil droplet movement was traced. Separation efficiency was also studied experimentally, and the diameter distributions of oil droplets at the inlet and the outlet of the separator were measured by a Malvern laser particle size analyser to verify the simulation model. Based on high-speed photography technology, the oil film distribution and flow pattern on the wall of the cyclone separator were visualised. The variation of oil-gas two-phase flow in the cyclone separator was compared under various inlet flow rates. Based on the results, an improved structure was proposed, and the performance of the improved separator was investigated experimentally.

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Preliminary study of coupling CFD code FLUENT and system code RELAP5

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Annals of Nuclear Energy 2014年 73卷 96-107页

作者： Wei Li Xiaoli Wu Dalin Zhang Guanghui Su Wenxi Tian Suizheng Qiu Department of Nuclear Science and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China

The present paper discusses a coupling strategy of the 3D (three-dimensional) computational fluid dynamics (CFD) code ANSYS-FLUENT with the best estimate 1. (one-dimensional) thermal–hydraulic system code RELAP5/MOD3.1. Preliminarily, by using DLL (Dynamic Link Library) technology and FLUENT UDF (User Defined Functions), an explicit coupling method expected to be able to support the analysis of multi-purpose thermal–hydraulic phenomena in nuclear reactor systems has been developed. Calculations for two test cases using the coupled FLUENT/RELAP5 code have been carried out to test and demonstrate the coupling capability: (i) the first one consisting of single-phase water transient flow in a square straight tube with well controlled mass flow rates; (ii) the second one illustrating the process of single-phase water flow in a system including two closed loops and one vessel, on which loss of loop water flow due to pump trip and increase of loop water temperature are studied. Both reasonable 1. systematic behaviors and 3D distribution information are naturally obtained for the test cases. Besides, a study of a highly transient experiment problem, i.e. Edwards–O’Brien pipe blowdown problem, has been performed by using the coupled FLUENT/RELAP5 code. The results are compared with standalone RELAP5 calculation and available experimental data, which shows the coupled FLUENT/RELAP5 code’s acceptable potential for the capability of analyzing either simple single-phase or complex two-phase flow problem.

关键词： Explicit coupling method DLL FLUENT RELAP5

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The development of Module In-vessel degraded severe accident Analysis Code MIDAC and the relevant research for CPR1.00 during the station blackout scenario

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Progress in Nuclear Energy 2014年 76卷 44-54页

作者： Jun Wang Wenxi Tian Yapei Zhang Lie Chen Longze Li Luteng Zhang Yukun Zhou Guanghui Su Suizheng Qiu State Key Laboratory of Multiphase Flow in Power Engineering Department of Nuclear Science and Technology Xi'an Jiaotong University Xi'an 710049 China

To meet the domestic demand of software autonomous scheduling, Xi'an Jiaotong University had developed MIDAC (a Module In-vessel degraded severe accident Analysis Code) which can not only analyze the processes of in-vessel severe accident, but also provide the related results of each one. This code was composed of five modules: the early behavior module, the core degradation module, the debris bed module, the melting materials IVR module and the connecting module. In this paper, the basic mathematic-physical models of those modules were briefly introduced. Then, the CPR1.00 station blackout scenario severe accident was set as an example to calculate the primary system thermal-hydraulic transient, the core degradation and the debris behavior, as well as the creep rupture of heat structures in primary loop pressure boundary. At last, the accuracy of MIDAC was verified in partial comparison with SCDAP/RELAP5 in primary system thermal-hydraulic transient analyzing part.

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MAAP5 simulation of the PWR severe accident induced by pressurizer safety valve stuck-open accident

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Progress in Nuclear Energy 2014年 77卷 141-151页

作者： Longze Li Yapei Zhang Wenxi Tian Guanghui Su Suizheng Qiu State Key Laboratory on Power Engineering and Multiphase Flow School of Nuclear Science and Technology Xi’an Jiaotong University Xi'an 710049 China

The Modular Accident Analysis Program version 5 (MAAP5) is a computer code that can simulate the response of light water reactor power plants during severe accident sequences. The present work aims to simulate the severe accident of a typical Chinese pressure water reactor (PWR) with MAAP5. The pressurizer safety valve stuck-open accident is essentially a small break loss-of-coolant accident (SBLOCA), which becomes one of the major concerns on core melt initiating events of the PWR. Six cases with different assumptions in the pressurizer (PZR) safety valves (SVs) stuck-open accident stuck open accident were analyzed for comparison. The results of first three cases show that the severe accident sequence is correlated with the number of the stuck open valve . The primary system depressurized faster in a more SVs stuck open case, and the consequences in which is hence slighter. The remaining 3 cases along with the case 2 were then analyzed to study the effect of operator intervention to the accident. The results show that the auxiliary feed water (AFW) is effective to delay the core degradation and hence delayed the finally system recovery. The high pressure injection (HPI) operation and manually opening the steam generator (SG) SVs are effective to mitigate this kind of severe accident. The results are meaningful and significant for comprehending the detailed process of PWR severe accident, which is the basic standard for establishing the severe accident management guidelines.

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Li-DOPED CERIUM TERNARY OXIDE IN CO2-SPLITTING VIA SOLAR THERMOCHEMICAL CYCLE

Li-DOPED CERIUM TERNARY OXIDE IN CO2-SPLITTING VIA SOLAR THE...

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1.th IUPAC International Conference on Novel Materials and their Synthesis NMS-X(IUPAC第十届新材料及其合成国际会议)

作者： YOUJUNLU CHUNLEI ZHANG LIYA ZHU State Key Laboratory of Multiphase Flow in Power Engineering Xi ''an Jiaotong UniversityXi ''an710049China

Ceria-based oxides have been wildly investigated for thermochemical two-step CO_2-splitting cycle. Among various dopants, cations with small ionic radius and/or multi-valence have shown obvious advantage and are believed to modify ceria in different way. Considering this, CeO_2 doped with both Li and transition metal (Ni, Fe, Cr) were synthesized via sol-gel method and tested for their CO_2-dissociation performance. The cycle proceeded at the reduction temperature of 1.73K through a ramp rate of 1.K/min and the oxidation temperature of 1.73K with a isothermal environment. Ce_(1.x)Li_xO_y(x=0,0.025,0.05,0.075,0.1. were tested at first. Ce_(0.975)Li_(0.025)O_y exhibited the best performance with the highest rate and yield of CO(5.23 mL·g-1.. Analysis shows that small radius and low valence of Li~+ lead to lattice disorder and high O~(2-) diffusion rate, which could enhance the Ce~(4+) reduction. Transition metal oxides (MO_x, M=Ni, Fe, Cr) were then added to Ce_(0.975)Li_(0.025)O_y, and among them, Ce_(0.935)Ni_(0.04)Li_(0.025)O_y exhibited the best performance with the highest rate and yield of CO(5.96 mL·g-1.. XPS analysis indicates that Ni~(2+) with better redox property could promote the reduction of Ce~(4+). Meanwhile Ce_(0.935)Ni_(0.04)Li_(0.025)O_y, and Ce_(0.955)Ni_(0.02)Li_(0.025)O_y also exhibited excellent performance. For the reduction step, nonisothermal kinetics analysis was performed and it turns out that the reduction process can be well discribed by shrinking core model. As for CO_2 splitting reaction, master plot method was used to determine the mechanism. Results indicate that the surface chemical reaction seem to be the controlling step.

关键词： ternary cerium oxide thermochemical cycle CO2-splitting Li

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