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Prediction of Dissociation Process of Ceramic Powder Materials under Plasma Heating Conditions

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Journal of Thermal Science 1993年第1期2卷 70-75页

作者： WangBoyi TianWendong InstituteofMechaincs ChineseAcademyofSciencesBeijing100080China InstituteofMechaincs ChineseAcademy

A model of the thermal dissociation process has been developed for the numerical simulation.of ceramic powder processing in a d. c. plasma reactor. The temperature histories of zircon grains were calculated based on this model. Comparisons were carried out to determine the effects of plasma gas (N_2 and Ar), free stream temperature (6000-15000K) and Reynolds number (0.0-1.0) as well as particle diameter (20-200μm) on the zircon dissociation process. The influences of proper Nusselt number correlation and variable transport properties were discussed in detail.

关键词： plasma heating ceramic powder thermal dissociation numerical simulation.

numerical simulation.and Analysis Of PCM on Phase Change Process Consider Natural Convection Influence

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Numerical Simulation and Analysis Of PCM on Phase Change Pro...

simulation.of oasis breeze circulation in the arid region of the Northwestern China

2012年计算机应用与系统建模国际会议

作者： Lin Qiu Min Yan Zhi Tan Beijing University of Civil Engineering and Architecture

A phenomenon of heat energy storage and release in phase change materials (PCM) which used in building retaining structure has been investigated. In the reality process of phase change, liquid phase has two ways of heat exchange: pure heat conduction and natural convection. To analyze the reality melting and solidification of PCM , set up the PCM heat transfer model which considering liquid-phase natural convection in this paper and exploit CFD software to carry out numerical simulation. The result shows that the influence of natural convection has mainly something about circumfluence generated by liquid phase, the direction of circumfluence which is opposite when heat and cool, the circumfluence intensity enhances as the height of phase interface increase.

关键词： Energy storage Phase change materials Natural convection numerical simulation.

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Science China Earth Sciences 2004年第Z1期47卷 101-107页

作者： LU Shihua, AN Xingqin & CHEN YuchunCold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China

In this paper, the process of oasis-desert circulation (ODC) is simulated by MM5V3.5 model through designing an ideal oasis-desert scheme and assuming that initial atmosphere is at rest (V= 0). The findings showed that the key of forming special oasis boundary structure is the difference of energy and water between oasis and desert. The evaporation of oasis surface consumes heat energy, and the low temperature of oasis causes an oasis breeze circulation (OBC), which drives an ODC with a downdraft over the oasis and an updraft over the desert. Later, the cold, dry and stable boundary over oasis is gradually formed, on the contrary, the atmospheric boundary over desert on the edge of oasis is hot, humid and unstable and its height is about 600 hPa. The updraft over the desert forms a wet ring that acts as a vertical wall weakening the low-level moisture exchange between the oasis and desert. The downdraft of OBC increases the atmospheric stability that reduces the oasis evaporation. The low-level outflow from the oasis (into the desert) prevents the dry, hot air flowing from the desert into the oasis. Thus an oasis self-preservation mechanism may be formed due to OBC. The horizontal area influenced by oasis is twice as oasis area and the vertical range is four times as oasis. The ODC is strong in the daytime and reaches the strongest at 17:00, and the influenced area is the largest at 20:00.

关键词： oasis atmospheric boundary layer numerical simulation.

The Stress State of the Beichuan-Jiangyou Segment of the Longmenshan Fault before and after the Wenchuan M_S 8.0 Earthquake

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Journal of Earth Science 2014年第5期25卷 861-870页

作者： Chengjun Feng Qunce Chen Chengxuan Tan Xianghui Qin Peng Zhang Wen Meng Institute of Geomechanics Chinese Academy of Geological Sciences Key Laboratory of Neotectonic Movement & Geohazard Ministry of Land and Resources

After the Wenchuan MS 8.0 Earthquake, which occurred on May 12, 2008, in Sichuan Province, China, we conducted a series of hydraulic fracturing stress measurements in three 200 m deep boreholes（ZK01, ZK02, and ZK03） drilled in Beichuan and Jiangyou regions near the northeastern segment of Longmenshan fault belt in 2009. These measurements revealed the near-surface stress field in the fault region one year after the Wenchuan MS 8.0 Earthquake. However, the lack of the stress measurements before the earthquake in the same region makes it difficult to understand variations of the in situ stress field（near-surface） by comparative analysis. In order to determine the unknown horizontal principal stresses before the earthquake in Beichuan and Jiangyou regions, the following research method was tentatively applied. Firstly, we calculate the static co-seismic stress field by linear elastic finite element numerical simulation.with ANSYS, based on the co-seismic static displacement generated by the Wenchuan MS 8.0 Earthquake along the central Longmenshan fault plane in Beichuan and Jiangyou. Secondly, combining hydraulic fracturing measurements（after the earthquake） with the co-seismic stress（simulation., the magnitudes and orientations of horizontal principal stresses before the earthquake were calculated. Finally, the variation of the in situ stress（near-surface） in Beichuan and Jinagyou, both before and after the Wenchuan MS 8.0 Earthquake, were obtained by comparative analysis. To do this the magnitude of SHmax was decreased on average by 13.01 and 6.54 MPa after the earthquake in ZK02 and ZK03, respectively and the magnitude of SHmin was decreased by 2.54 and 5.29 MPa in ZK02 and ZK03, respectively. Following the earthquake, the average direction of SHmax rotated anticlockwise by 42.5°.

关键词： Longmenshan fault belt hydraulic fracturing situ stress co-seismic stress numerical simulation.

Mathematical modeling approach to the transmission dynamics of pine wilt disease with saturated incidence rate

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International Journal of Biomathematics 2018年第3期11卷 77-96页

作者： Muhammad Altaf Khan Kamil Shaht Yasir Khan Saeed Islam Department of Mathematics City University of Science and Information Technology Peshawar Khyber Pakhtunkhwa 25000 Pakistan Department of Mathematics University of Haft A1 Batin Hafr Al Batin 31991 Saudi Arabia Department of Mathematics Abdul Wall Khan University Mardan Khyber Pakhtunkhwa 23200 Pakistan

The present paper investigates the dynamics of pine wilt disease with saturated incidence rate. The proposed model is stable both locally and globally. The local stability of the disease-free equilibrium is determined by the basic reproduction R0. The disease-free equilibrium is stable locally and globally whenever R0〈 1. If R0 〉 1, then the endemic state is stable both locally and globally. Further, a brief discussion with conclusion on the numerical results of the proposed model is presented.

关键词： SEIVRS mathematical model pine wilt disease stability analysis numerical simulation.

A comparative study on 3-D solar wind structure observed by Ulysses and MHD simulation

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Science Bulletin 2005年第7期50卷 672-678页

作者： FENG Xueshang, XIANG Changqing, ZHONG Dingkun & FAN Quanlin SIGMA Weather Group, Key Laboratory of Space Weather Key Labo- ratory of Geospace Environment and Geodesy, Ministry of Education, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080, China SIGMA Weather Group Key Laboratory of Space Weather Beijing China Key Labo-ratory of Geospace Environment and Geodesy Ministry of Education Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China

During Ulysses’ first rapid pole-to-pole transit from September 1994 to June 1995, its observations showed that middle- or high-speed solar winds covered all latitudes except those between ?20° and +20° near the ecliptic plane, where the velocity was 300―450 km/s. At poleward 40°, however, only fast solar winds at the speed of 700―870 km/s were observed. In addition, the transitions from low-speed wind to high-speed wind or vice versa were abrupt. In this paper, the large-scale structure of solar wind observed by Ulysses near solar minimum is simulated by using the three-dimensional numerical MHD model. The model com- bines TVD Lax-Friedrich scheme and MacCormack II scheme and decomposes the calculation region into two re- gions: one from 1 to 22 Rs and the other from 18 Rs to 1 AU. Based on the observations of the solar photospheric magnetic field and an addition of the volumetric heating to MHD equations, the large-scale solar wind structure mentioned above is reproduced by using the three-dimensional MHD model and the numerical results are roughly consistent with Ulysses’ observations. Our simulation.shows that the initial magnetic field topology and the addition of volume heating may govern the bimodal structure of solar wind observed by Ulysses and also demonstrates that the three-dimensional MHD numerical model used here is efficient in modeling the large-scale solar wind structure.

关键词： Ulysses observation solar wind structure numerical simulation.

Dynamics of SVEIS epidemic model with distinct incidence

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International Journal of Biomathematics 2015年第6期8卷 99-117页

作者： N. Nyamoradi M. Javidi B. Ahmad Department of Mathematics Faculty of Sciences Razi University 67149 Kermanshah Iran Faculty of Mathematical SciencesUniversity of Tabriz Tabriz Iran Department of Mathematics Faculty of Science King Abdulaziz University P. O. Box 80203 Yeddah 21589 Saudi Arabia

In this paper, we study the global dynamics of a SVEIS epidemic model with distinct incidence for exposed and infectives. The model is analyzed for stability and bifurcation behavior. To account for the realistic phenomenon of non-homogeneous mixing, the effect of diffusion on different population subclasses is considered. The diffusive model is analyzed using matrix stability theory and conditions for Turing bifurcation are derived. numerical simulation. support our analytical results on the dynamic behavior of tile model.

关键词： SVEIS epidemic model diffusion Turing bifurcation stability basic repro-duction number numerical simulation.

Passive Control of Condensation Shock Wave in Prandtl-Meyer Expansion Flow

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Journal of Thermal Science 2003年第1期12卷 20-26页

作者： Shigeru Matsuo Masanori Tanaka Toshiaki Setoguchi Heuy-Dong Kim Department of Mechanical Engineering Saga UniversityDepartment of Mechanical Engineering Saga UniversityDepartment of Mechanical Engineering Saga UniversitySchool of Mechanical Engineering College of Natural Science Andong National University 388 1 Honjo-machi Saga-shi Saga 840-8502 Japan1 Honjo-machi Saga-shi Saga 840-8502 Japan 1 Honjo-machi Saga-shi Saga 840-8502 Japan Song-Cheon Dong Andong Kyung-Pook Korea

In this paper, the effects of the passive technique by using the slotted wall on the characteristics of a condensation shock wave generated in a Prandtl-Meyer flow were investigated experimentally. Furthermore, in order to clarify the variation of condensation properties in the flow field, Navier-Stokes equations were solved numerically using a 3rd-order MUSCL type TVD finite-difference scheme with a second-order fractional-step for time integration. Baldwin-Lomax model was used as a turbulence model in the computations. From experimental results, it was found that the shock strength on the slotted wall became weak in comparison with no passive case (solid wall), and the present passive technique was the most effective when a foot of the condensation shock wave was located at the middle of slotted wall. Furthermore, it was confirmed numerically that the passive technique was also effective for the unsteady condensation shock wave.

关键词： compressible flow Prandtl-Meyer flow condensation shock wave numerical simulation.

Dynamic analysis of a fractional order system

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International Journal of Biomathematics 2015年第6期8卷 157-173页

作者： M. Javidi N. Nyamoradi Faculty of Mathematical SciencesUniversity of Tabriz Tabriz Iran Department of Mathematics Faculty of Sciences Razi University 67149 Kermanshah Iran

In this paper, we investigate the dynamical behavior of a fractional order phytoplankton- zooplankton system. In this paper, stability analysis of the phytoplankton zooplankton model （PZM） is studied by using the fractional Routh-Hurwitz stability conditions. We have studied the local stability of the equilibrium points of PZM. We applied an efficient numerical method based on converting the fractional derivative to integer derivative to solve the PZM.

关键词： Phytoplankton-zooplankton model Routh-Hurwitz stability conditions numerical simulation.