检索结果-内蒙古大学图书馆

Experimental and numerical study on flow separation control in rectangle diffuser

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical engineering 2010年第5期30卷 92-99页

作者： Xie, Yong-Hui Fan, Tao Zhang, Di Ye, Dong-Ting Wang, Shun-Sen State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi Province China

To investigate the mechanism of active control for flow separation in rectangle diffuser by vortex generator jets (VGJs) method, numerical analysis with large-eddy simulation and experimental measurement by particle image velocimetry (PIV) were carried out for the flow field. The numerical results show good agreement with experimental data. The two dimensional vortical structure was discussed in detail via the analysis of their velocity and vorticity distribution. Based on the three dimensional identification of vortex, several vortical structure, with emphasis on the dynamic process of its generation and development, was also discussed. The results show that the jet shear-layer vortices evolved from vortex loops to vortex rings as time go on. Horseshoe vortices wrap around the jet nozzle have the strong stability. The counter-rotating vortex pair has mean-flow definition although they may also have unsteady components. Moreover, to investigate the effect of VGJs on separation control, the surface pressure coefficient, the length of separation zone, the flow characteristics in diffuser and pressure power spectra were compared with and without VGJs. It revealed the longitudinal vortices generate at the downstream of jet increase cross-stream mixing of streamwise momentum and then suppress or delay the separation in diffuser. © 2010 *** ***.

关键词： Large eddy simulation

来源：评论

学校读者我要写书评

暂无评论

Research on the Preparation of (CuAg)xIn2xZn2(1−2x)S2 Solid Solution Photocatalysts

引用

AIP Conference Proceedings 2010年第1期1207卷 1066-1069页

作者： K. Zhang D. W. Jing C. J. Xing L. J. Guo State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University China

ZnS‐CuInS2‐AgInS2 solid solution photocatalysts were successfully prepared by co‐precipitation method with heat treatment under different atmosphere ( N2 and H2S). XRD, XRF, UV‐vis, and SEM were used to characterize the prepared photocatalysts, indicated that the composition of result photocatalysts were different from each other and also the rate of charge, though they possessed a wurtzite‐type phase structure. The photocatalysts all showed photocatalytic activities for H2 evolution from aqueous solutions containing SO32− and S2− as sacrificial reagents under visible light irradiation with Ru loading, but sample treated under H2S atmosphere performed better, the possible reason was proposed.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Emission Characteristics and Axial Flame Temperature Distribution of a Circumferential Reverse flow Combustor

引用

Journal of Energy and power engineering 2010年第7期4卷 9-14页

作者： C. Dong Q.L. Zhou X.G. Zhang P. Sun T.M. Xu S.E. Hui Q.X. Zhao State Key Laboratory of Multiphase Flow in Power Engineering Xi ＇an Jiaotong University Xi ＇an 710049 China

In partially premixed combustion of gas turbine, the combustion temperature should be lowed in order to reduce NOx. One solution is lean premixed combustion. However, the problem is that large excess air ratio may make the combustion unstable. A novel combustor with circumferential reverse flow of fuel gas is proposed for settling this problem. A 10 kw furnace is established to test performance of this combustor. Three factors such as primary air ratio, position of secondary air, total excess air ratio are studied. The emission characteristics and axial flame temperature distribution are studied. Basing on experimental results, the axial flame temperature and NOr emission increase with primary air ratio and axial length of second stream, and decrease with total excess air ratio. When the total excess air ratio is larger than 1.05, the combustor presents a lower temperature field and much lower NOx emission （less than 10 ppm）.

关键词： Partially premixed combustor secondary air distributor NOx emission axial flame temperature experimentalinvestigation.

来源：评论

学校读者我要写书评

暂无评论

Experimental Study of Falling Film on the Outside of Horizontal Tube

引用

AIP Conference Proceedings 2010年第1期1207卷 238-243页

作者： L. B. Yan H. X. Li B. Guo Y. Q. Zhang Z. Zhang Y. F. Zhang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China

Evaporating falling film on horizontal tubes has been widely used in desalinization, refrigeration, chemical process industries, and so on. In this paper, the flow characteristics of falling film outside horizontal tubes in horizontal air flows was studied theoretically and experimentally. Two low patterns of the falling film, i.e., droplet flow pattern and columnar flow pattern, were considered. Effects of the velocity of airflow, the flux of falling film flow, the external diameter of tube and the surface property of tube on the falling film flowing characters were investigated. Experimental study indicated that, in a definite flow scale, as the flow increased, the diameters of falling droplets and falling columns of the liquid enlarged, and the liquid film became thick and the area covered by the liquid film increased. As the air velocity increased, the offset of the droplet and the column to the top of the tube enlarged, and the rate of increase come down until it complete depart from the the top of the horizontal tube. Besides, a theoretical model was established about the offset of the droplet and liquid column from the top of the tube under the force of the horizontal air flows, and the model was validated by a comparison between the numerical predictions and experimental data.A further analysis about the excursion law of falling film flow outside horizontal tube was also made at the last paprt of the paper.

关键词：

来源：评论

学校读者我要写书评

暂无评论

1‐Dodecane‐sulfonic‐acid‐sodium‐salt(LAS) assisted hydrothermal synthesis of CdxZn1−xS solid solution as efficient photocatalysts under visible light irradiation

引用

AIP Conference Proceedings 2010年第1期1207卷 1048-1052页

作者： B. Jia L. J. Guo aState Key Laboratory of Multiphase Flow in power Engineering Xi’an Jiaotong University China bState Key Laboratory of Multiphase Flow in power Engineering Xi’an Jiaotong University China

With anionic surfactant LAS assisted, series of zinc cadmium sulfide semiconductor photocatalysts were synthesized by hydrothermal method. These products were characterized by X‐ray diffraction (XRD), UV‐Vis absorption spectra (UV‐Vis) and scanning electron microscopy (FESEM). The photocatalytic activities of as‐prepared samples were evaluated by photocatalytic hydrogen production from water under visible‐light irradiation. The best synthesis parameters are: Composition 0.9:0.1 (Cd:Zn molar ratio), Temperature 160 °C, Hydrothermal Time 48 Hour, LAS Concentration 1.7 mmol/L, the maximum visible‐light‐catalytic hydrogen production rate is 161.25 μmol/h (λ>430 nm) which is higher than those of by coprecipitation method. The experiment results indicate that surfactant assisted hydrothermal method is an effective way to get highly active CdZnS solid solution photocatalyst.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Simulation of a standing‐wave thermoacoustic engine using compressible SIMPLE algorithm

引用

AIP Conference Proceedings 2010年第1期1207卷 939-944页

作者： Dongwei Zhang Yaling He Yong Wang Jing Huang aState Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University China

In present paper, a two‐dimensional numerical study on a standing‐wave thermoacoustic engine was performed with compressible SIMPLE algorithm based on a pressure‐correction method. First, the simulation model was developed, and the time‐dependent compressible thermoacoustic engine system was chosen through substantive numerical tests. Appropriate governing equations for mass, momentum and energy were introduced. Then, the computational results of the onset of the self‐excited oscillations across the entire evolution process and the acoustical characteristics of the pressure and velocity wave were presented and analyzed. In addition, the standing‐wave of the pressure and velocity along the center of the two stacks are investigated. The crucial nonlinear phenomenon that cannot be captured by the existing linear theory, like high harmonic frequencies, is also revealed in present paper. It is concluded that compressible SIMPLE algorithm could be employed in our future work to simulate and optimize thermoacoustic system. The present result is an important step toward development to predict the high‐amplitude thermoacoustic systems and optimize thermoacoustic engine performance.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Experimental Research on the Performance of Exhaust Steam Reclaim Device With a Swirling flow Vane

引用

AIP Conference Proceedings 2010年第1期1207卷 374-379页

作者： X. L. Li J. J. Yan P. F. Zhang J. J. Yang J. P. Liu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University P.R. China

This paper experimentally studied the performance of exhaust steam reclaim device with a swirling flow vane at different inlet water pressures, temperatures, different inlet steam pressures and different distances between the throat and spout. The results indicated that the injection coefficient decreased as the inlet water pressure and temperature increased, respectively. There is a best distance between the throat and spout which makes the injection coefficient reached to its maximal value at the same experimental pressure and temperature, and the value equals to 130 mm in our experimental system. The resistance coefficient has a minimum value which makes the device have the highest outlet water pressure. Compared with the device without a swirling flow vane, it improves the heating performance for higher injection coefficient and exergy efficiency.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Optical Analysis of Fresnel lens for concentrating PV system

引用

AIP Conference Proceedings 2010年第1期1207卷 244-251页

作者： F. Q. Cui Y. L. He R. J. Xu Y. B. Tao aState Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University China

Concentrating PV systems usually use Fresnel lens as radiation concentrator. In this paper, in order to study the concentrating performance of the Fresnel lens, modular Fresnel lens mode was developed and its optical performance was analyzed by the ray tracing method. The imaging characteristic of Fresnel was studied and the optimal imaging location and the size of dispersion spot with different inlet angle were figured out. Flux distribution of the different imaging plane were also examined and compared. The results show that the dispersion spot deviates from the focus and the size of the dispersion spot is enlarged as the incidence angle increase, especially at the high geometric concentration ratio. Then in order to solve the problem, a flat light pipe was applied to reflect sun light onto the absorber plane. The simulation results show that with the new design, sun lights with large inlet angle could also be casted on the absorber.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Research on the Hydrodynamic Characteristics and Metal Temperature Distribution in Spiral tube Water Wall of an Ultra Supercritical Boiler

引用

AIP Conference Proceedings 2010年第1期1207卷 199-204页

作者： Weijing Zhang Dong Yang Jie Pan Xu Zhou State Key Lab of Multiphase Flow in Power Engineering Xi’an Jiaotong University China

On the basis of a 350 MW supercritical pressure OTSC boiler, established the mathematical model for the circulation loop flow and grid pressure in a complex flow network system, and an iteration method was used to solve the nonlinear equations. The water wall flow distribution and temperature profile of the boiler were computed. The results show that the flow difference and heat difference are small in spiral tube water wall at BMCR, 75%BMCR load and 30%BMCR load. The metal temperatures are all in the range of allowable range, and the operation of boil is safe and reliable.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Slagging characteristics on the superheaters of a 12 MW biomass-fired boiler

Slagging characteristics on the superheaters of a 12 MW biom...

引用

作者： Niu, Yanqing Tan, Hongzhang Ma, Lin Pourkashanian, Mohamed Liu, Zhengning Liu, Yang Wang, Xuebin Liu, Haiyu Xu, Tongmo State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xian Jiaotong University Xian 710049 China School of Process Environmental and Materials Engineering University of Leeds Leeds LS2 9JT United Kingdom

In an attempt to understand the problem of severe slagging in biomass-fired boilers, slags formed on the fourth-, second-, and first-stage superheaters in a 12 MW biomass-fired grate furnace have been collected, sampled, and analyzed using X-ray fluorescence (XRF) and X-ray diffraction (XRD) techniques. The slag collected on each superheater has a unique morphology and structure. The slag on the fourth-stage superheater is loose and porous, while on the secondary and the primary superheaters, the slag shows a clear layered structure of different colors and levels of hardness. Aluminosilicate is the major component in the slag on the fourth-stage superheater, which is formed by Si, Al, and alkali species. On both the secondary and primary superheaters, the sticky sylvine, potassium calcium sulfate, and aphthitalite in the bottom layer trap coarse, large particles, resulting in further slagging. In the alternating layers, the particles containing high concentrations of K, Na, and Cl form the initial deposit layer, the yellow layer in the secondary superheater. Then, it traps the coarse, large particles containing high Si, Al, Ca, Mg, and Fe to form the brown layer. Similarly, the particles in the pale-yellow layer of the primary superheater containing high concentrations of K, Na, and Cl form the initial deposit layer, and then, it traps the coarse, large particles containing high Si, Al, Ca, Mg, and Fe to form the black layer. Accompanied by the periodic blowing, the alternating layer is formed and the slag gradually becomes thicker. © 2010 American Chemical Society.

关键词： Iron

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：