Gan Y.,North China Institute of Aerospace Engineering |
Xu A.,CAS Beijing Institute of Applied Physics And Computational Mathematics |
Zhang G.,CAS Beijing Institute of Applied Physics And Computational Mathematics |
Yang Y.,China Petroleum Pipeline Bureau
EPL | Year: 2013
We present a simple and general approach to formulate the lattice BGK model for high-speed compressible flows. The main point consists of two parts: an appropriate discrete equilibrium distribution function (DEDF) feq and a discrete velocity model with flexible velocity size. The DEDF is obtained by feq = C-1M, where M is a set of moments of the Maxwellian distribution function, and C is the matrix connecting the DEDF and the moments. The numerical components of C are determined by the discrete velocity model. The calculation of C-1 is based on the analytic solution which is a function of the parameter controlling the sizes of discrete velocity. The choice of the discrete velocity model has a high flexibility. The specific-heat ratio of the system can be flexible. The approach works for the one-, two- and three-dimensional model constructions. As an example, we compose a new lattice BGK kinetic model which works not only for recovering the Navier-Stokes equations in the continuum limit but also for measuring the departure of the system from its thermodynamic equilibrium. Via adjusting the sizes of the discrete velocities, the stably simulated Mach number can be significantly increased up to 30 or even higher. The model is verified and validated by well-known benchmark tests. Some macroscopic behaviors of the system due to the deviation from thermodynamic equilibrium around the shock wave interfaces are shown. © EPLA, 2013.
Zhang J.,North China Institute of Aerospace Engineering |
Ling C.,China Petroleum Pipeline Bureau
Applied Mechanics and Materials | Year: 2014
In this paper, the stability of discrete singular bilinear systems is discussed by the method of Lyapunov function. Some asymptotic stability criterions are given according to the equivalent system and the equivalent transformation, and the regularity is considered. © (2014) Trans Tech Publications, Switzerland.
Gao H.,China Petroleum Pipeline Engineering Corporation |
Li G.,China Petroleum Pipeline Engineering Corporation |
Ma X.,China Petroleum Pipeline Engineering Corporation |
Guo J.,China Petroleum Pipeline Engineering Corporation |
Ma J.,China Petroleum Pipeline Bureau
ICPTT 2011: Sustainable Solutions for Water, Sewer, Gas, and Oil Pipelines - Proceedings of the International Conference on Pipelines and Trenchless Technology 2011 | Year: 2011
This paper presents eight horizontal directional drilling crossing cases and their problems and solutions. These crossings were conducted by horizontal directional drilling company of petroleum pipeline bureau in China, and to make it clear, these crossings are classified into three categories according to the major geological conditions. © 2011 ASCE.
Zhang X.,Chongqing Jiaotong University |
Liu J.,China Petroleum Pipeline Bureau
Advanced Materials Research | Year: 2011
Because double side drift excavation method named eye excavation method has been a mature and reliable excavation method, it has normally been used in tunnels with super cross-section and super large section area. However, the construction speed using this method is very slow. One of reasons is that the construction technology of this method would be more and complex. The other is that all construction workers, materials, equipment would be extremely difficult for their up and down, and that the ballast rock would have to be moved by artificial when the upper step of the middle guide hole would be excavated. In this paper, to speed up the process of excavating tunnel with super cross-section and super large section area underpass extra-high building, the elastic-plastic numerical simulations for the tunnel named Industry and Trade Station of the third line in Chongqing Rail Transit were made in four excavation methods conditions. The four excavation methods is respectively the double side drift excavation method to the first excavation in main building side, the double side drift excavation method to the first excavation in podium side, the single side drift excavation method in the upper step to the first excavation in main building side and the single side drift excavation method in the upper step to the first excavation in podium side. The main building is named Industry and Trade building with 22 floors. The results showed that the single side drift excavation method in the upper step could Insure the building and tunnel when the support measures were reasonable, that the guide hole beside the little surface load should firstly be excavated by whether double side drift excavation method or single side drift excavation method, and that these would provide a reference for some similar engineering. © (2011) Trans Tech Publications, Switzerland.
Di X.J.,Tianjin University |
An X.,Tianjin University |
Cheng F.J.,Tianjin University |
Wang D.P.,Tianjin University |
And 2 more authors.
Science and Technology of Welding and Joining | Year: 2016
The inter-critically reheated coarse-grained heat-affected zone (ICCGHAZ) of X70 pipeline steel with different second peak temperature and heat input was simulated in this study by means of Gleeble3500 simulator. The volume fraction, size, shape and distribution of martensite–austenite (M–A) constituent were analysed. The toughness of ICCGHAZ and corresponding fractographs were examined. The results showed that the distribution of M–A was strongly influenced by second peak temperature, and M–A constituent with necklace structure at lower second peak temperature led to worse toughness. The volume fraction and size of M–A were strongly affected by heat input, the volume fraction of M–A constituent increased with the increase of heat input; the volume fraction and size of M–A were key factors of toughness deterioration; the interfacial energies and the initiation of crack were related to the shape of M–A constituent. © 2016 Institute of Materials, Minerals and Mining.