检索结果-内蒙古大学图书馆

7th Asia-Pacific Conference on Combustion, ASPACC 2009

作者： Yu, W. Wei, L.X. Ma, Z.H. Huang, Z.H. Yuan, T. Tian, Z.Y. Li, Y.Y. State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei230029 China

Low pressure premixed laminar n-heptane/propane/O2/N2 flames were investigated with tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam sampling mass spectrometry. Three flames with different mass percentage of propane in the fuel blends of 0%, 10%, and 20% were studied. The combustion intermediates were identified by comparing the measured IEs with those values in literatures. Mole fraction profiles of the main species were compared among the three flames. The experimental results provide detailed experimental data in understanding the combustion of n-heptane and n-heptane/propane blends in engine. They are also helpful in establishing and verifying the kinetic model. © 2009 Combustion Institute. All rights reserved.

关键词： Combustion

来源：评论

学校读者我要写书评

暂无评论

Two-phase flow instability in parallel nine-channel system under rolling condition

引用

Yuanzineng Kexue Jishu/Atomic Energy Science and Technology 2009年第10期43卷 886-892页

作者： Zhang, You-Jia Su, Guang-Hui Qiu, Sui-Zheng Guo, Yu-Jun State Key Laboratory of Multiphase Flow in Power Engineering Department of Nuclear Science and Technology Xi'an Jiaotong University Xi'an 710049 China

Two-phase flow instability in parallel multi-channel system was studied under rolling motion condition. A parallel nine-channel model was established by using the control volume integrating method based on the homogeneous flow model with considering the rolling motion condition. The gear method was used to solve the control equations. The influences of the entrance, upward sections and the heating power on the flow instability under rolling motion condition were analyzed. The marginal stability boundary (MSB) under rolling motion condition was obtained. The unstable regions occur in both low and high equilibrium quality regions. The region with low inlet sub-cooling is also unstable. In high equilibrium quality region, the multiplied period phenomenon is found and the chaotic phenomenon appears at the MSB.

关键词： Stability

来源：评论

学校读者我要写书评

暂无评论

Numerical simulation of predicting and reducing solid particle erosion of solid-liquid two-phase flow in a choke

引用

Petroleum Science 2009年第1期6卷 91-97页

作者： Li Guomei Wang Yueshe He Renyang Cao Xuewen Lin Changzhi Meng Tao State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇an Shaanxi 710049 China China Special Equipment Inspection and Research Institute Beijing 100013 China School of Transport ＆ Storage and Civil Engineering China University of Petroleum Qingdao Shandong 266555 China Petroleum Exploration and Production Research Institute Sinopec Beijing 100083 China

Chokes are one of the most important components of downhole flow-control equipment. The particle erosion mathematical model, which considers particle-particle interaction, was established and used to simulate solid particle movement as well as particle erosion characteristics of the solid-liquid two-phase flow in a choke. The corresponding erosion reduction approach by setting ribs on the inner wall of the choke was advanced. This mathematical model includes three parts： the flow field simulation of the continuous carrier fluid by an Eulerian approach, the particle interaction simulation using the discrete particle hard sphere model by a Lagrangian approach and calculation of erosion rate using semiempirical correlations. The results show that particles accumulated in a narrow region from inlet to outlet of the choke and the dominating factor affecting particle motion is the fluid drag force. As a result, the optimization of rib geometrical parameters indicates that good anti-erosion performance can be achieved by four ribs, each of them with a height （H） of 3 mm and a width （B） of 5 mm equaling the interval between ribs （L）.

关键词： Solid-liquid two-phase flow discrete particle hard sphere model choke erosion rate antierosion numerical simulation

来源：评论

学校读者我要写书评

暂无评论

Numerical studies on natural circulation precooling loop of cryogenic liquid rocket engine

引用

Hangkong Dongli Xuebao/Journal of Aerospace power 2009年第3期24卷 698-704页

作者： Chen, Er-Feng Li, Yan-Zhong Cheng, Xiang-Hua School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

One set of one-dimensional unsteady homogenous mathematic models for flow and heat process of natural circulation precooling loop of cryogenic liquid rocket engine was established, whilst both inverted annular model and dispersed model were introduced for the prediction of filming boiling region. The results indicate the unstable characteristics of circulation flow rate in precooling process is caused by the unstable characteristics of natural circulation driving force, that is, the heat flux transferred to the cryogenic liquid from the natural circulation precooling loop. Moreover, about 80% of wall temperature drop takes place in filming boiling region, and the inverted temperature distribution law of the return pipe is well interpreted by introducing the two filming boiling models mentioned above.

关键词： Rockets

来源：评论

学校读者我要写书评

暂无评论

Atmospheric Pb levels over Mount Qomolangma region

引用

Particuology 2009年第3期7卷 211-214页

作者： Renjian Zhang Zhenxing Shen Han Zou Key Labaratory of Regional Climate-Environment Research far Temperate East Asia (REC-TEA) Institute of Atmaspheric Physics Chinese Academy of Sciences Beijing 100029 China State Key Laboratory of Multiphase Flaw in Power Engineering Deportment of Environmental Science and Engineering Xi'an Jiaotong University Xi'An 710049 China

The Pb spectral concentration of atmospheric aerosol samples observed over Mount Qomolangma site （28° 11＇33＂N, 86°49＇S9＂E, 4950m ASL） in 2002 was 13.3 ng/m^3, about 4.5 times higher than that in 2000. The Pb spectral distribution showed three peaks, located at 〈0.25 μm, 0.5-1 μm, and 4-8 μm in diameters. The peaks for 〈0.25 μm and 0.25-0.5 μm may be due to long-distant transport, while that for 4-8 μm probably results from local floating dust. The atmospheric Pb concentration over Mount Momolangma was lower than that of South Pole, most of the urban areas, and desert areas in the northern hemisphere. The enrichment factors for fine and coarse particles of atmospheric Pb in 2002 over Mount Qomolangma were 413.2 and 62,6, respectively, in support of the slight atmospheric pollution with Pb over the Qinghai- Tibetan Plateau.

关键词： Pb Mount Qomolangma Enrichment factor

来源：评论

学校读者我要写书评

暂无评论

Lattice Boltzmann model for axisymmetric thermal flows

引用

Physical Review E 2009年第3期80卷 037702-037702页

作者： Q. Li Y. L. He G. H. Tang W. Q. Tao National Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an Shaanxi 710049 China

A thermal lattice Boltzmann (LB) model is presented for axisymmetric thermal flows in the incompressible limit. The model is based on the double-distribution-function LB method, which has attracted much attention since its emergence for its excellent numerical stability over the multispeed LB method. Compared with the existing axisymmetric thermal LB models, the present model is simpler and retains the inherent features of the standard LB method. Numerical simulations are carried out for the thermally developing laminar flows in circular ducts and the natural convection in an annulus between two coaxial vertical cylinders. The Nusselt number obtained from the simulations agrees well with the analytical solutions and/or the results reported in previous studies.

关键词： Numerical methods

来源：评论

学校读者我要写书评

暂无评论

Modeling and optimization for increasing propylene in FCC gasoline secondary reactions process based on LM/SVM method

Modeling and optimization for increasing propylene in FCC ga...

引用

The 5th Joint China/Japan Chemical engineering Symposium

作者：周小伟杨伯伦袁俊 Department of Chemical Engineering State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong University

To improve the efficiency of parameters selection for support vector machines(SVM),a novel method of Levenberg-Marquardt(LM) algorithm coupling with SVM,called LM/SVM,was developed in this *** new method was applied in modeling and optimization for increasing propylene in secondary reaction of FCC *** LM algorithm was adopted in LM/SVM method to optimize the multiple parameters of the SVM model as to overcome the problem of difficult to selecting the parameters for SVM and to fit relational expression of high *** strategy which divided the training data into working data to train SVM and the testing data to avoid over-fitting was *** of LM/SVM with reported genetic algorithm based support vector regression indicated that LM/SVM had better generalization ability and higher *** performance of LM/SVM employing polynomial kernel was *** agreement between predicted results and experimental data suggested that the LM/SVM method was successfully developed and the SVM model for increasing propylene was well *** quadratic programming(SQP) algorithm was employed to optimize the operation conditions for maximizing the propylene yield of secondary *** proposed model was claimed to accurately predict the yields of propylene and liquefied petrochemical gas(LPG).

关键词： secondary reactions propylene support vector machines Levenberg-Marquardt algorithm

来源：评论

学校读者我要写书评

暂无评论

Kramers' problem and the Knudsen minimum: A theoretical analysis using a linearized 26-moment approach

Kramers' problem and the Knudsen minimum: A theoretical anal...

引用

作者： Gu, Xiao-Jun Emerson, David R. Tang, Gui-Hua Computational Science and Engineering Department STFC Daresbury Laboratory Warrington WA4 4AD United Kingdom School of Energy and Power Engineering State Key Lab of Multiphase Flow Xi'An Jiaotong University Xi'an 710049 China

A set of linearized 26 moment equations, along with their wall boundary conditions, are derived and used to study low-speed gas flows dominated by Knudsen layers. Analytical solutions are obtained for Kramers' defect velocity and the velocity-slip coefficient. These results are compared to the numerical solution of the BGK kinetic equation. From the analysis, a new effective viscosity model for the Navier-Stokes equations is proposed. In addition, an analytical expression for the velocity field in planar pressure-driven Poiseuille flow is derived. The mass flow rate obtained from integrating the velocity profile shows good agreement with the results from the numerical solution of the linearized Boltzmann equation. These results are good for Knudsen numbers up to 3 and for a wide range of accommodation coefficients. The Knudsen minimum phenomenon is also well captured by the present linearized 26-moment equations. © 2009 Springer-Verlag.

关键词： Method of moments

来源：评论

学校读者我要写书评

暂无评论

New Technology of Thermodynamic Cycle for Waste Heat Recovery of Vehicle Gasoline Engine

New Technology of Thermodynamic Cycle for Waste Heat Recover...

引用

IEEE PES Asia-Pacific power and Energy engineering Conference (APPEEC)

作者： Xin Xin Zhang Ke Zeng Mao Gang He State Key Laboratory of Multiphase Flow in Power Engineering Xi''an Jiaotong University Xi'an Shaanxi China

In this paper, the exothermic distribution of fuel was studied detailedly through conducting thermal equilibrium experiment when the vehicle gasoline engine was at different working conditions. Considering the characteristic of the exhaust temperature of the vehicle gasoline engine, the Organic Rankine Cycle (ORC) was adopted for the exhaust recovery. The thermodynamic parameter and thermodynamic performance of the main state points in the ORC were theoretically calculated via computer program. The optimal parameter was determined. On this basis, the organic working fluids were selected. In the last part, a new thermodynamic cycle configuration which can be used to recover the heat from exhaust gas, cooling water and lubricant of vehicle gasoline engine was put forward and introduced.

关键词： Thermodynamics Heat engines Heat recovery Waste heat Vehicles Petroleum Fuels Thermal conductivity Employee welfare Temperature

来源：评论

学校读者我要写书评

暂无评论

Comparative analysis of single droplet evaporation models in Cryogen Spray Cooling

引用

Kung Cheng Je Wu Li Hsueh Pao/Journal of engineering Thermophysics 2009年第4期30卷 653-656页

作者： Xin, Hui Zhou, Zhi-Fu Chen, Bin Wang, Guo-Xiang Wang, Yue-She State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China Department of Mechanical Engineering University of Akron Akron OH 44325 United States

Cryogen Spray Cooling is used for cooling human skin during selected laser treatment of Port Wine Stain. Transient state cryogen spray involves intricate droplets evaporation, intense heat convection and mass transfer. In present paper, mass transfer equation of single droplet evaporation model for cryogen spray equilibrium evaporation stage was improved and the effect of seven gas phase models on single droplet evaporation characteristic in R-134a cryogen spray is compared. It is pointed out that the gas phase model which takes the effect of superheat into account was most coincidence with experiment data. A parametric study of the influences of initial diameter and velocity on the droplet evaporation is then carried out by this gas phase model.

关键词： Heat convection

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：