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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

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

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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.

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

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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.

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Experimental Study of Falling Film on the Outside of Horizontal Tube

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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.

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Measurement and control system in process of carbon dioxide capture based on sparse support vector machine

Measurement and control system in process of carbon dioxide ...

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Global Congress on Intelligent Systems

作者： Yan, Liwei Lu, Hongfang Yu, Yunsong Zhang, Xu Li, Yun Zhang, Zaoxiao State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 China

ISBN: (纸本)9780769543048

Capturing CO2 from the flue gas of a power plant based on chemical absorption method is an effective way to cut down the emission of CO2. However, the principal components in the solvent are very difficult to be measured online. Therefore an online measurement and control system was designed for the process of capturing CO2 by MEA chemical absorption. The feature selection was done according to Bayesian networks. Furthermore based on the principle of a new sparse support vector machine (SLS-SVM), the measurement of ionic species distribution in the absorption solution was predicted, and the results agreed well with the data obtained by Nuclear Magnetic Resonance (NMR) measurement. The mean square error is 3.8645×10-7. The measurement of solution species distribution was carried out online by using infrared sensors and NMR technology. Meanwhile the sampling system and NMR unit were linked for the online analysis based on variable-temperature and variable-pressure NMR technology. Finally a measurement and control platform was constructed based on VI technology. It shows that the performance of traditional equipment can be improved by the novel system, which will provide a more effective method for CO2 capture process. © 2010 IEEE.

关键词： Bayesian networks

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

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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.

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THE VELOCITY FIELD OF multiphase flow AND EFFICIENCY OF BIOLOGICAL AERATION FILTER

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Journal of Hydrodynamics 2010年第2期22卷 260-264页

作者： CHENG Wen HU Bao-wei YANG Chun-di CHENG Wen-juan Environment Research Institute Xian University of Technology Xi＇an 710048 China State Key Laboratory of Multiphase Flow in Power Engineering Xi＇ an Jiaotong University Xi＇an 710049 China Key Laboratory of Northwest Water Resources and Environmental Ecology of Education Ministry Xi＇anUniversity of Technology Xi＇an 710048 China Yuanpei College Shaoxing University Shaoxing 312000 China Environment Research Institute Xi＇an University of Technology Xi＇an 710048 China

Aeration is an important factor affecting the biological aeration *** a set of experiment device specially designed for the purpose,and the particle image velocimetry technique,the velocity field of the gas-liquid two-phase flow is studied under different *** various simulated aeration states were actually applied to the experimental device of sewage treatment,and the results of the numerical simulation were *** final experimental results indicate that the most efficient state occurs when the ratio of water in aeration tank h / w =1,the diameter of capillary tubes d=0.6mm and the velocity of bubbles v=0.3m/s.

关键词： ratio of water diameter of capillary tube bubbles velocity sewage disposal efficiency

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Numerical simulation of a buried hot crude oil pipeline during shutdown

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Petroleum Science 2010年第1期7卷 73-82页

作者： Xu Cheng Yu Bo Zhang Zhengwei Zhang Jinjun Wei Jinjia Sun Shuyu Beijing Key Laboratory of Urban Oil and Gas Distribution Technology China University of Petroleum Beijing 102249China Zhejiang Department Preparatory Team PetroChina West East Gas Pipeline Company Hangzhou Zhejiang 310000 China State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇an Shaanxi 710049 China Department of Mathematical Sciences Clemson University Clemson SC 29634-0975 USA

In this paper a mathematical model is built for a buried hot crude oil pipeline during shutdown, and an unstructured grid and polar coordinate grid are respectively applied to generating grids for the soil region and the three layers in the pipe （wax layer, pipe wall, and corrosion-inhibiting coating）. The governing equations are discretized using the finite volume method. The variations in temperatures of static oil and soil were investigated during pipeline shutdown in both summer and winter, in which some important parameters of the soil and crude oils of a Northeast pipeline are employed.

关键词： Moving boundary stagnation point equivalent thermal conductivity thermal influence region unstructured grid

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Experimental study on the characteristics of weak corrosive surfactant drag reducer

Experimental study on the characteristics of weak corrosive ...

引用

12th International Conference on Engineering, Science, Construction, and Operations in Challenging Environments - Earth and Space 2010

作者： Su, Wen-Tao Li, Feng-Chen Dong, Yong Cai, Wei-Hua Jiao, Li-Fang Wei, Jin-Jia Yu, Bo School of Energy Science and Engineering Harbin Institute of Technology Harbin 150001 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiao Tong University Xi'an 710049 China Beijing Key Laboratory of Urban Oil and Gas Distribution Technology China University of Petroleum Beijing 102249 China

ISBN: (纸本)9780784410967

Experimental study on drag-reducing characteristics of a zwitterionic surfactant additive (C20H43NO) in a circulation system has been carried out. It was based on the optimum concentration, temperature effect and the characteristics of resisting shear in DN27.5 pipeline. The results showed that C20H43NO additive has a significant drag-reducing effect depending on concentration and temperature. The most effective concentration in the tested flow loop was 900ppm at 60°C. The temperature range of the drag-reducing effect was in the range of 40 ∼ 70°C. The maximum drag reduction (DR) of 900ppm C20H 43NO aqueous solution was 77% at the beginning of circulation with system running between 41°C and 43°C. The drag-reducing effect does not decrease remarkably after the circulation system ran for a period of seven hours, but reduces to only 5% of DR after a period of twenty-three hours. In order to study the drag-reducing characteristics of C20H 43NO aqueous solution in the practical district heating system, the experiments with C20H43NO aqueous solution flow in different inner-diameter pipelines including DN50 and DN100 with rough wall were performed. The results indicated that the optimum drag-reducing concentrations are 1500ppm and 2500ppm at 45∼50°C in the DN50 and DN100 circular pipes, respectively. Finally, the technique of drag-reducing additive applying into the district heating system is discussed. And some problems in the practical application were brought forward, such as, the poor life-span of surfactant, the instabilities of drag-reducing effect and the inherent corrosion of additive itself. According to these problems, the corrosion research of C 20H43NO aqueous solution was also conducted based on immersion method. The results show that: C20H43NO aqueous solution is weakly corrosive for iron-based metallic pipe comparing with CTAC aqueous solution and water. © 2010 ASCE.

关键词： Pipelines

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Exergy analysis of solar dynamic closed Brayton cycle for space applications

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Taiyangneng Xuebao/Acta Energiae Solaris Sinica 2010年第3期31卷 351-356页

作者： Chen, Shuangtao Hou, Yu Chen, Liang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 China

Exergy analysis of solar dynamic closed Brayton cycle (SDCBC) for space applications was presented in this paper. An integrated model for the system and specific models for its components were proposed. Influence of main parameters on system exergy efficiency was discussed. The results shown the efficiencies of expander, compressor, and regenerating temperature of the regenerator have significant influence on the exergy efficiency of SDCBC system. Therefore, besides the enhancement of component efficiencies, the matching among components of SDCBC system should be also taken into account. Moreover, it would be always desirable to enhance the effectiveness of recuperator within the requirements of flow resistance and system weight.

关键词： Space applications

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