检索结果-南通市图书馆

Effect of inlet volute wrap angle on the flow field and performance of double inlet gas cyclones

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2023年第6期77卷 29-36页

作者： Zetao Wang guogang sun Zhengyuan Song Shiwei Yuan Zhen Qian College of Mechanical and Transportation Engineering China University of PetroleumBeijing102249China State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China

In response to the divergent understanding of double inlet cyclone performance in the literature,the effect of inlet volute wrap angle on the performance and flow field of double inlet cyclone separator was studied by Computational Fluid Dynamic(CFD)*** results showed that the inlet volute wrap angle can affect the comparison results of the single and double inlet gas cyclones with the same total inlet cross-sectional area and velocity.0°and 90°volute double inlet improved the efficiency mainly by separating particles below 10μm,while 180°volute double inlet had no separation advantage for any particles,so the symmetrical double inlet does not always improve the efficiency,and the appropriate inlet volute wrap angle should be selected according to the actual situation,otherwise,the expected performance requirements of the symmetrical double inlet cyclone cannot be *** with the flow field,it is found that the inlet volute wrap angle changed the tangential velocity of the sym-metrical double inlet cyclone separator,thus changing the performance.

关键词： Cyclone separator Inlet volutewrapangle Efficiency Pressure drop Double inlet

Effects of Expansion Chamber on the Flow Pattern and Performance of Cyclones

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Petroleum Processing & Petrochemical Technology 2017年第2期19卷 114-122页

作者： Han Xiao sun guogang sun Zhanpeng Han Xiaopeng State Key Laboratory of Heavy Oil Processing China University of Petroleum Beijing 102249 Beijing Key Laboratory of Process Fluid Filtration and Separation Beijing 102249

To improve the performance of the Stairmand cyclone, the effects of an expansion chamber on the flow field, the pressure drop and the separation efficiency were investigated numerically and experimentally. The experimental results showed that compared with the Stairmand cyclone, the cyclone with an upper expansion chamber worked better at low inlet velocity(less than 14 m/s in this study), while the cyclone with a lower expansion chamber achieved higher efficiency at a relatively high inlet velocity(14-20 m/s). The presence of an expansion chamber can generally result in a slight decrease in the cyclone pressure drop. The simulated results, which were used to further analyze the reason behind the experimental phenomena, suggested that the expansion chamber had insignificant effects on the tangential velocity profiles in the cylindrical part of cyclones. While in the cone part, the expansion chamber and the dipleg, the tangential velocity slightly decreased. Nevertheless, the expansion chamber decreased the possibility of the vortex end to sweep the wall and then reduce the particle re-entrainment. Therefore, installing the expansion chamber at a proper position could improve the separation performance of Stairmand cyclones. Both the experimental and simulated results represent a potential improvement of the Stairmand cyclone performance.

关键词： expansion chamber numerical simulation flow field separation efficiency

Numerical Simulation of Particle Concentration in a Gas Cyclone Separator

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2007年第3期4卷 76-83页

作者： Xue Xiaohu sun guogang Wan Gujun Shi Mingxian School of Chemical Science and Engineering China University of Petroleum Beijing 102249 China

The particle concentration inside a cyclone separator at different operation parameters was simulated with the FLUENT software. The Advanced Reynolds Stress Model （ARSM） was used in gas phase turbulence modeling. Stochastic Particle Tracking Model （SPTM） and the Particle-Source-In-Cell （PSIC） method were adopted for particles computing. The interaction between particles and the gas phase was also taken into account. The numerical simulation results were in agreement with the experimental data. The simulation revealed that an unsteady spiral dust strand appeared near the cyclone wall and a non-axi-symmetrical dust ring appeared in the annular space and under the cover plate of the cyclone. There were two regions in the radial particle concentration distribution, in which particle concentration was low in the inner region （r/R≤0.75） and increased greatly in the outer region （r/R〉0.75）. Large particles generally had higher concentration in the near-wall region and small particles had higher concentration in the inner swirling flow region. The axial distribution of particle concentration in the inner swirling flow （r/R≤0.3） region showed that there existed serious fine particle entrainment within the height of *** above the dust discharge port and a short-cut flow at a distance of about 0.25D below the entrance of the vortex finder. The dimensionless concentration in the high-concentration region increased obviously in the upper part of the cyclone separation space when inlet particle loading was large. With increasing gas temperature, the particle separation ability of the cyclone was obviously weakened.

关键词： Cyclone separator particle concentration distribution simulation

Study on the Hydrodynamic Characteristics of Venturi-Rod Deck Tray

在线全文

学校读者我要写书评

暂无评论

China Petroleum Processing & Petrochemical Technology 2017年第3期19卷 97-104页

作者： Liu Jianxin sun guogang Wang Xincheng Zhao Fei State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing 102249

The Venturi-rod deck tray is a type of dual flow trays used in flue gas desulfurization(FGD) process. In this paper, the hydrodynamic characteristics of the Venturi-rod deck tray were studied in the experiments and compared with the conventional sieve tray. Results showed the turndown ratio of this tray was in the range of 2.71—3.77, which was by 9% higher than the sieve tray. Besides, the pressure drop of this tray was by more than 50% lower than the sieve tray. Based on the experimental data, the correlation functions for the pressure drop and the froth height, respectively, were obtained. The industrial scale up practice of this tray in FGD process was described with the efficiency of this tray demonstrated.

关键词： dual flow tray scrubber Venturi hydrodynamic characteristics

Investigation of Different Coke Samples Adhering to Cyclone Walls of a Commercial RFCC Reactor

在线全文

学校读者我要写书评

暂无评论

China Petroleum Processing & Petrochemical Technology 2016年第1期18卷 8-14页

作者： Li Xiaoman Song Jianfei sun guogang Yan Chaoyu Wei Yaodong State Key Laboratory of Heavy Oil Processing China University of Petroleum

The microstructure and properties of the coke samples collected from 4 different wall regions of the cyclone in the reactor of a residue fluid catalytic cracking unit(RFCCU) were analyzed by using the scanning-electron microscope(SEM), and the possible coke formation processes were investigated as well. The results showed that some of the heavy nonvolatile oil droplets entrained in the flowing oil and gas mixture could possibly deposit or collide on the walls by gravity settling or turbulence diffusion, and then were gradually carbonized into solid coke by condensing and polymerization along with dehydrogenation. Meanwhile some of fine catalyst particles also built up and integrated into the solid coke. The coke can be classified into two types, namely, the hard coke and the soft coke, according to its property, composition and microstructure. The soft coke is formed in the oil and gas mixture's stagnant region where the oil droplets and catalyst particles are freely settled on the wall. The soft coke appears to be loose and contains lots of large catalyst particles. However, the hard coke is formed in the oil and gas mixture's flowing region where the oil droplets and catalyst particles diffuse towards the wall. This kind of coke is nonporous and very hard, which contains a few fine catalyst particles. Therefore, it is clear that the oil and gas mixture not only carries the oil droplets and catalyst particles, but also has the effects on their deposition on the wall, which can influence the composition and characteristics of deposited coke.

关键词： FCC reactor cyclone coke formation microstructure characteristics

Stochastic analysis of particle-fluid two-phase flows

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2000年第9期45卷 806-810页

作者： sun guogang LI Jinghai GONG Fuzhou LUO Shunlong MA Zhiming Institute of Chemical Metallurgy Chinese Academy of Sciences100080 BeijingChina Institute of Applied Mathematics Chinese Academy of Sciences100080 BeijingChina

This paper is devoted to exploring approaches to understanding the stochastic characteristics of particle-fluid two-phase flow. By quantifying the forces dominating the particle motion and modelling the less important and/or unclear forces as random forces, a stochastic differential equation is proposed to describe the complex behavior of a particle motion. An exploratory simulation has shown satisfactory agreement with phase doppler particle analyzer (PDPA) measurements, which indicates that stochastic analysis is a potential approach for revealing the details of particle-fluid flow phenomena.

关键词： two-phase flow random force stochastic simulation and modelling.

NUMERICAL SIMULATION OF FINE PARTICLE SEPARATION IN A ROTATIONAL TUBE SEPARATOR

在线全文

学校读者我要写书评

暂无评论

China Particuology 2005年第4期3卷 219-223页

作者： Jinyu Jiao Ying Zheng guogang sun Department of Chemical Engineering University of New Brunswick 15 Dineen Drive P.O. Box 4400 Fredericton N.B. E3B 5A3 Canada Departments of Chemical Engineering University of Petroleum Beijing 102249 P. R. China

This paper presents a numerical analysis of gas-solid separation in a rotational tube separator. This separator which collects fine particles from gas in laminar flow is effective for fine particle separation. The separation efficiency and critical particle diameter of the separator were simulated using CFD package （FLUENT 6.0）. The simulation showed that separation efficiency can be significantly decreased due to the presence of turbulence. The simulation also showed that the Saffman lift force has little effect on the efficiency of this separator. The critical particle diameter of this tube separator was also calculated theoretically, Some experimental data were provided to validate the simulation results. Comparison between experimental results and simulation predictions on separation efficiency showed satisfactory agreement.

关键词： fine particle separation numerical simulation rotational tube separator

Modeling the gas flow in a cyclone separator at different temperature and pressure

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2010年第4期4卷 498-505页

作者： Gujun WAN guogang sun Cuizhi GAO Ruiqian DONG Ying ZHENG Mingxian SHI State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing 102249China Department of Chemical Engineering University of New BrunswickPO Box 4400FrederictonNB CanadaE3B 5A3

The gas flow field in a cyclone separator,operated within a temperature range of 293 K-1373 K and a pressure range of 0.1-6.5 MPa,has been simulated using a modified Reynolds-stress model(RSM)on commercial software platform FLUENT *** computational results show that the temperature and pressure significantly influence the gas velocity vectors,especially on their tangential component,in the *** tangential velocity decreases with an increase in temperature and increases with an increase in *** tendency of the decrease or increase,however,reduces gradually when the temperature is above 1000 K or the pressure goes beyond 1.0 *** temperature and pressure have a relatively weak influence on the axial velocity *** outer downward flow rate increases with a temperature increase,whereas it decreases with a pressure *** centripetal radial velocity is strong in the region of 0-0.25D below the vortex finder entrance,which is named as a short-cut flow zone in this *** on the simulation results,a set of correlations was developed to calculate the combined effects of temperature and pressure on the tangential velocity,the downward flow rate in the cyclone and the centripetal radial velocity in the short-cut flow region underneath the vortex finder.

关键词： cyclone separator high temperature high pressure flow field numerical simulation

Neuropeptide Y and nestin expression in the hippocampal CA3 region following restrained and inverted stress in rats

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2011年第3期6卷 206-212页

作者： sun, guogang Chen, Bo Fan, Guangbi Xiao, Hongwen Chen, Yue Xu, Jie Nie, Ye Zhang, Bing Gong, Lin Li, Ailing Luzhou Med Coll Dept Anat Luzhou 646000 Sichuan Peoples R China Luzhou Med Coll Dept Nucl Med Affiliated Hosp Luzhou 646000 Sichuan Peoples R China sun Yat Sen Univ Sch Preclin Med Dept Human Anat Guangzhou 510080 Guangdong Peoples R China Luzhou Med Coll Sch Humanities & Social Sci Luzhou 646000 Sichuan Peoples R China Luzhou Keyuan Biotechnol Co Ltd Luzhou 646000 Sichuan Peoples R China Luzhou Med Coll Dept Histol & Embryol Luzhou 646000 Sichuan Peoples R China Luzhou Med Coll Dept Publ Hlth Luzhou 646000 Sichuan Peoples R China

Our preliminary study demonstrated that neuropeptide Y （NPY）/nestin-positive cells exhibit a consistent spatial distribution in the hippocampus of normal adult rats. However, following severe acute and chronic stress-induced impaired learning and memory, synchronous decreased expression of nestin and NPY takes place in the hippocampus, and the underlying mechanisms remain unclear. In the present study, acute and chronic stress rat models were established using combined restrained and inverted stress. Results showed that learning and memory significantly decreased in acute and chronic stress rats. In addition, hippocampal cells were damaged, in particular in the acute stress rats, and nestin and NPY expression, as well as the number of NPY/nestin-positive cells in the CA3 region, significantly decreased. Furthermore, mature neurofilament 200-positive neurons were absent in the chronic stress rats. The NPY and cytoskeletal protein system equally contributed to stress-induced early learning and memory deficits as well as sustained cerebral iniurv in the adult hippocampus.

关键词： CA3 region learning and memory neuropeptide Y nestin restrained and invertedstress rats