Applied Mechanics and Materials Vols. 275-277

Abstract: A fast approach to high-speed train co-simulation between aerodynamics and train-track coupling dynamics is presented. With this method, the fluid-structure dynamic performances of a high-speed train are simulated with different crosswind velocity and train velocity. The aerodynamic forces and train dynamics are compared under off-line simulation and equilibrium state method. Considering the fluid-structure interaction, there is significant influence on the head aerodynamics and train dynamics. The results show that it is necessary to consider changing attitude in crosswind

Abstract: A novel adaptive method for singular geometric regions was proposed. Combined with conventional cut cell adaption, curvature cell adaption and solution adaption, adaptively refined Cartesian grid was automatically generated after geometries had been specified by users. Solid wall boundary was implemented by ghost body-cell method which efficiently relieved the time step restriction of small cut cells. Flow field was well resolved on adaptively refined Cartesian grid with finite volume method. Transonic flow around the RAE2822 airfoil and subsonic flow around the Suddhoo four-element airfoil are carefully investigated, which validate the efficiency of current approach and its feasibility in complicated geometric regions.

Abstract: Through the establishment of the mixture model and the discrete phase model of aerosol cooling, the heat transfer characteristics between the aerosol and high temperature die steel plate are studied. When the discrete phase volume fraction is greater than 10%, mixed convection heat transfer model is used to study the effect of the gas-water volume fraction on heat transfer characteristics; when the discrete phase volume fraction is less than 10%, the discrete phase model is used to study the effect of the discrete phase mass flow rate and particle size on the heat transfer characteristics. The results can provide important references for the die steel quenching equipment design and production.

Abstract: In order to study the impact of the different structures in the air-suction seed metering device of no-tillage planter on seeding performance, based on the structural characteristics of vacuum chamber in air-suction seed metering device of no-tillage planter, the air flow finite element analysis of air-suction seed metering device and experimental verification were did. Mainly the law of the distribution of airflow field and seeding performance of the vacuum chamber under the situation of the different distribution diameters of the suction hole were studied in this paper. The result shows that the adsorption performance is best when the suction hole distribution diameter is 150 mm. The conclusion can provide a reference for structural optimization and performance improvement of the air-suction seed metering device of no-tillage planter.

Abstract: Calculation and optimization of hydraulic parameters remains one of major challenges when planning and drilling deepwater wells. Based on traditional drilling theory and the characteristics of deepwater drilling, the particularity of deepwater drilling hydraulic parameters design is analyzed. According to the different features of the riser segment, inclined segment and horizon segment, the method for calculating the optimum displacement is proposed in segmental way. Besides, an applicable optimization method is presented for designing deepwater drilling parameters. The predicted value exhibits good agreement with measured value in drilling field, and it has practically guiding significance to deepwater drilling hydraulic parameters design.

Abstract: Designed a new type of double inlet cylindrical cyclone. For search the separation performance in a cylindrical cyclone. By use of CFD，applied the RSM turbulence model and Euler two-phase flow method and ASM which to simulate separation process and flow field within a double inlet cylindrical cyclone. Then compared with the single inlet cyclone，obtained velocity distribution. Analyzed the differences of discrete phase volume fraction between different viscosity. The results show that the new-style cyclone caught more stable fluid field and higher separation efficiency. And when the viscosity is about 0.75 kg/m•s， the separation efficiency and stability of the oil core is higher. Preliminary flow field law is shown up.

Abstract: As an important component of large-scale extruder system for polymer material, Die-plate can be regarded as the final determinant for pelletization uniformity. Polymer melt was shaped in shaping channels and extruded from die-holes from Die-plate and then be diced. The design of shaping channels directly influences the uniformity for polymer-melt extrusion pressure and extrusion velocity of different die holes. In this paper, a three-dimensional flow model for polymer flow in Die-plate channel was presented, and then finite element simulation was used to analyze the distribution of extrusion velocity in each die-hole. Based on simulation result, a BP neural network model was applied to analyze the relationship between geometry factors of Die-plate, such as length of shaping channels, die hole extrusion velocity distribution, and extrusion uniformity. This optimization method can be used in the design of Die-plate to improve effect and quality of actual polymer production and processing.

Abstract: The numerical investigations presented in this paper deal with wind tunnel testing scheme design for 1/4 scaled MIRA model including supporting system. Based on the structure of aerodynamic and aero-acoustic full scale wind tunnel, using computational fluid dynamics (CFD), focus on MIRA model and supporting system, the drag force of scaled models and supporting system were calculated. By comparing with the wind tunnel testing results and drag force coefficient of reference, it is certain that the wind tunnel testing scheme is available and effective and that the value calculated by CFD is in good agreement with experiments.

Abstract: The computational fluid dynamics (CFD) software is used to compute three-dimensional concentric heat exchanger in this research. In order to reduce the burden of the computational time, the concentric heat exchanger is simplified sector of 5° for the regular arrangement of internal shape. The working fluids for hot flow and cold flow are helium and molten salt individually. The arrangements for hot and cold flow paths within a heat exchanger is opposite. This study is mainly focused on the distribution of field for the two layers of concentric heat exchanger. The width of the flow channel as well as the length, pitch, thickness and angle of fin have been changing to analyze the effectiveness-NTU method. The results showed that the best heat transfer of fin thickness, angle, space, length, and flow channel are under 5mm, 5°, 8mm, 44mm, and 12mm, respectively.

Abstract: Elliptical flow exists in the near vertical fracture area, or in anisotropic reservoirs, and the classical radial flow models cannot provide complete analysis for elliptical flow. This paper presents a mathematic model for gas elliptical flow in double porosity gas reservoirs. The differential equation of gas flow is written in Mathieu equation, so that the solution can be expressed also by Mathieu functions. The numerical calculation of relevant Mathieu functions , and its derivative is done to obtain the dimensionless pseudo pressure drop in Laplace space. Property sensitivities of double porosity systems including combination of , parameter related to anisotropy, storativity ratio , interporosity flow coefficient are studied by using the Laplace numerical inversion. The new solution not only includes factors considered for classic solutions in previous papers, but also incorporates the effect of reservoir anisotropy. It is kind of modification and supplementation to classic solutions.