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Theoretical investigation on the steady-state natural circulation characteristics of a new type of pressurized water reactor

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Nuclear Science and Techniques 2006年第5期17卷 314-320页

作者： GOU Jun-Li QIU Sui-Zheng SU Guang-Hui JIA Dou-Nan State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇an 710049 China

This article presents a theoretical investigation on the steady-state natural circulation characteristics of a new type of pressurized water reactor. Through numerically solving the one-dimensional steady-state single-phase conservative equations for the primary circuit and the steady-state two-phase drift-flux conservative equations for the secondary side of the steam generator, the natural circulation characteristics were studied. On the basis of the pre- liminary calculation analysis, it was found that natural circulation mass flow rate was proportional to the exponential function of the power and that the value of the exponent is related to the operating conditions of the secondary side of the steam generator. The higher the outlet pressure of the secondary side of the steam generator, the higher the pri- mary natural circulation mass flow rate. The larger height difference between the core center and the steam generator center is favorable for the heat removal capacity of the natural circulation.

关键词：核反应堆压水堆稳态自然循环高度差理论研究

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Analysis of flow instabilities in forced-convection steam generator

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Nuclear Science and Techniques 2006年第3期17卷 185-192页

作者： WU Ge-Ping QIU Sui-Zheng SU Guang-Hui JIA Dou-Nan State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇ an 710049 China

Because of the practical importance of two-phase instabilities, substantial efforts have been made to date to understand the physical phenomena governing such instabilities and to develop computational tools to model the dynamics. The purpose of this study is to present a numerical model for the analysis of flow-induced instabilities in forced-convection steam generator. The model is based on the assumption of homogeneous two-phase flow and ther- modynamic equilibrium of the phases. The thermal capacity of the heater wall has been included in the analysis. The model is used to analyze the flow instabilities in the steam generator and to study the effects of system pressure, mass flux, inlet temperature and inlet/outlet restriction, gap size, the ratio of do / di, and the ratio of qi / qo on the system be- havior.

关键词：蒸汽发生器强迫对流流动不稳定性双相不稳定性

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An investigation of flow characteristics and critical heat flux in vertical upward round tube

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Nuclear Science and Techniques 2006年第3期17卷 170-176页

作者： FAN Pu QIU Sui-Zheng JIA Dou-Nan State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇an 710049 China

Prediction of critical heat flux (CHF) in annular flow is important for the safety of once - through steam generator and the reactor core under accident conditions. The dryout in annular flow occurs at the point where the film is depleted due to entrainment, deposition, and evaporation. The film thickness, film mass flow rate along axial distribution, and CHF are calculated in vertical upward round tube on the basis of a separated flow model of annular flow. The theoretical CHF values are higher than those derived from experimental data, with error being within 30%.

关键词：环流临界热通量沉积挟带核反应堆工程

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Experimental analysis on adjusting performance of vapor-liquid two-phase flow controller

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Journal of Harbin Institute of Technology(New Series) 2006年第5期13卷 525-530页

作者：李慧君屠珊 School of Energy and Power Engineering North China Electric Power UniversityBaoding 071003ChinaState Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

The vapor-liquid self-adjusting controller is an innovative automatic regulating *** order to ensure adjusted objects run safely and economically,the controller automatically adjusts the liquid flux to keep liquid level at a required level according to physical properties of vapor-liquid two-phase *** adjusting mechanics,the controller’s performance and influencing factors of its stability have been analyzed in this *** theoretical analysis and successful applications have demonstrated this controller can keep the liquid level steady with good *** actual application in industry has shown that the controller can satisfactorily meet the requirement of industrial production and has wide application areas.

关键词： vapor-liquid two-phase flow adjusting performance liquid level controller

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Development of Liquid Slug Length in Gas-Liquid Slug flow along Horizontal Pipeline: Experiment and Simulation

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Chinese Journal of Chemical engineering 2006年第5期14卷 626-633页

作者：王鑫郭烈锦张西民 State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University

The liquid slug length distribution is crucial for designing the downstream processing system with mul-tiphase pipeline. Experiments were conducted in a 133m long horizontal test loop. The measurements were per-formed by conductivity probes to determine the liquid slug length distribution. The data covered both the slug and plug flow regimes. From experimental results, the mean liquid slug lengths were relatively insensitive to gas and liquid flow rates in the higher mixture velocity range. But in the lower mixture velocity range, the mean liquid slug length decreased and then increased with mixture velocity. It shows that the development length of slug flow was longer than x/D=1157. A slug tracking model was adapted to study the evolution of liquid slug length distribution in a horizontal pipeline. In the present model, the wake effect of elongated bubble and the pressure drop due to accel-eration are taken into account and random slug lengths are introduced at the entrance. The results of the model are compared with the measured slug length distributions of slug flow regime. It shows that the predicted mean and maximum slug lengths are in agreement with the experimental data at x/D=1157 and the form of the slug length distributions is also predicted well by the model.

关键词： two-phase flow slug flow liquid slug length slug tracking

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Experimental research on dryout point of flow boiling in narrow annular channels

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Nuclear Science and Techniques 2006年第4期17卷 252-256页

作者： WU Ge-Ping QIU Sui-Zheng SU Guang-Hui JIA Dou-Nan LU Dong-Hua State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇an 710049 China Reactor Engineering Research Division Nuclear Power Institute of China Chengdu 610041 China

An experimental research on the dryout point of flow boiling in narrow annular channels under low mass flux with 1.55 mm and 1.05 mm annular gap, respectively, is conducted. Distilled water is used as working fluid and the range of pressure is limited within 2.04.0 MPa and that of mass flux is 26.069.0 kg·m(?2)·s(?1). The relation of critical heat flux (CHF) and critical qualities with mass flux and pressure are revealed. It is found that the critical qualities decrease with the increasing mass flux and increase with the increasing inlet qualities in externally heated annuli. Under the same conditions, critical qualities in the outer tube are always larger than those in the inner tube. The appearance of dryout point in bilaterally heated narrow annuli can be judged according to the ratio of qo/qi. key words: Narrow annular channel; flow boiling; Dryout point

关键词：临界热通量流动沸腾干燥核沸腾狭窄环形通道

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An investigation on heat transfer to supercritical water in inclined upward smooth tubes

An investigation on heat transfer to supercritical water in ...

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作者： Yin, Fei Chen, Ting-Kuan Li, Hui-Xiong National Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China National Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

Within the range of pressures from 23 to 30 MPa, mass velocities from 600 to 1200 kg/(m 2 s), and heat fluxes from 200 to 600 kW/m 2 , experiments have been performed for an investigation on heat transfer to supercritical water in inclined upward smooth tubes with an inner diameter of 26 mm and an inclined angle of 20° from the horizon. The results indicated that heat transfer characteristics of supercritical water are not uniform along the circumference of the inclined tube. An increase in the mass velocity of the working fluid can decrease and even eliminate the non-uniformity. Properties of supercritical fluid acutely vary with the temperature near the pseudocritical point. While the ratio of the mass velocity to the heat flux exceeded 2.16 kg/(kWs), heat transfer enhancement occurred near the pseudocritical point;conversely, heat transfer deterioration occurred while the ratio of the mass velocity to the heat flux was lower than 2.16 kg/(kWs). As the pressure increased far from the critical pressure, the amount of deterioration decreased. Correlations of heat transfer coefficients of the forced-convection heat transfer on the top and bottom of the tube have been provided, and can be used to predict heat transfer coefficient of spirally water wall in supercritical boilers.

关键词： Pipe flow

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Numerical investigation of edl effects on the flow characteristics of polar fluids in rectangular microchannels

Numerical investigation of edl effects on the flow character...

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4th International Conference on Nanochannels, Microchannels and Minichannels, ICNMM2006

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

ISBN: (纸本)0791847608

Recently, a large number of experiments have been conducted to examine the applicability of Navier-Stokes equations to predict the friction factor for the laminar flow of polar fluids in microchannels. However, significant discrepancies still exist between various results. In order to investigate the effect of electric double layer on the pressure-driven flow of polar fluid in smooth rectangular microchannels and to reveal whether continuum model can still be applied, numerical investigations are conducted in this paper. The simulated microchannels are made of silicon engraved substrate with Pyrex cover, and the measured relative roughness of channels is less than 0.5%. Deionized water and tap water with different ion concentration and electrical conductivity are used as the working fluid. The governing equations include the two-dimensional, non-linear Poisson-Boltzmann equation, the modified N-S equation and the electric field Ez equation. The steady state electric field E z equation is coupled with the momentum equation. The FVM (finite volume method) is adopted to discretize the governing equations. The non-uniform grid systems 152×102 is applied and the Reynolds number ranges from 0.1 to 300. Good agreements are achieved between the numerical results and the experimental data available in the literature. The effects of electrical potential, fluid ion concentration, electrical conductivity and the channel dimensions on the EDL profile, and the electroviscous effect and the friction coefficient are presented in detail. The simulation results reveal that the Debye thickness depends on ion concentration greatly. Only when the ratio of Dh/δ (the ratio of channel hydraulic diameter to the Debye thickness) is low, the electroviscous effect should be considered. According to the experimental conditions, the numerical results show that if the ratio of Dh/δ is greater than 15, the predicted friction factors agree well with the macroscale classical law, and the disparities

关键词： Channel flow

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Synthesis of a novel ZnMoS4 photocatalyst and its performance for photocatalytic production of hydrogen

Synthesis of a novel ZnMoS4 photocatalyst and its performanc...

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16th World Hydrogen Energy Conference 2006, WHEC 2006

作者： Liang, Huirong Liu, Guanjie Zhang, Yaojun Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University 710049 Xi'an China

ISBN: (纸本)9781622765409

The production of hydrogen by photocatalytic decomposition of water using zinc tetrathiomolybdate catalyst was studied. Zinc tetrathiomolybdate catalyst was prepared by coprecipitation and hydrothermal method based on ZnSO 4 and self-prepared [NH4]2MoS4 crystal. It was characterized by XRD, XRF, BET and UV-Vis spectra. The photocatalytic activities of the catalysts were ascertained by the production of hydrogen in an aqueous Na2S-Na2SO3 solution under the ultraviolet and visible light irradiation. It was observed that the photocatalysts showed the visible-light photocatalytic activity, and the ZnMoS4 photocatalyst prepared under hydrothermal condition for about 24h had the highest activity.

关键词： Photocatalysts

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WS2 sensitized mesoporous TiO2 for efficient photocatalytic hydrogen production from water under visible light

WS2 sensitized mesoporous TiO2 for efficient photocatalytic ...

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16th World Hydrogen Energy Conference 2006, WHEC 2006

作者： Jing, Dengwei Guo, Lie-Jin Xing, Chanjuan Yan, Qiuhui State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049 China

ISBN: (纸本)9781622765409

Nanosize WS2 sensitized mesoporous TiO2 was prepared to extend the adsorption of the wide band gap TiO2 into visible light region. Compared with nonporous particle TiO2 substrate, it was found that the existence of mesopore is important for larger amount of WS 2 loading and inhibition of the light-induced detachment of WS 2 particles from the TiO2 substrate during photocatalytic reaction, which leads to higher photocatalytic activity and stability. We also found that the rate-determining step for photocatalytic hydrogen production is the transfer of electrons from TiO2 substrate to H+ in solution, when the recombination between electrons and holes within TiO 2 could be neglected. In this case, deposition of Pt at the surface of semiconductor is indispensable for efficient hydrogen production.

关键词： Titanium dioxide

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