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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Yue-long Bai) Jun Xu) Zhi-feng Zhang) Wei-min Mao) Hong Xu) ) General Research Institute for Non-ferrous Metals Beijing China ) School of Materials Science Engineering University of Science Technology Beijing Beijing China ) Research Center for Foundry Engineering North University of China Taiyuan China 《北京科技大学学报(英文版)》2009,16(4):422-426
The effect of injection pressure, piston velocity, and the forming temperature of semisolid slurry on the filling behavior of the semi-solid A356 aluminum alloy was investigated by simulation methods. The simulation results show that these processing parameters have an important effect on the filling behavior of the semi-solid A356 aluminum alloy. The slurry flows steadily in the cavity when the injection pressure, the piston velocity, and the forming temperature are low, but it is prone to turbulent flow w... 相似文献
992.
In order to investigate Joule heating power, a three-dimensional finite element model (FEM) was developed to predict Joule
heating power in the channels of double-loop inductor. The simulated results were compared with experimental data from low
load trials for a 400 kW inductor. The results, such as power factor and Joule heating power, show reasonable correlation
with experimental data, and Joule heating rate reaches the maximum at the corners and the minimum at the centre of the cross-section
area. With increasing relative permeability of iron core, length of coils, current frequency and resistivity of metal melt,
the power factor and Joule heating power change. It is concluded that current frequency, the resistivity and length of the
coil play a critical role in determining the power factor and Joule heating power, whereas relative permeability of the magnetic
core shows no significant influence on them. 相似文献
993.
A new hydraulic system of a novel automatic transmission (AT) was designed. The dimension and structure of valves and cylinders
were designed by theoretical calculation. The dynamic simulation model of hydraulic system of AT was established by ITI-SimulationX.
Simulation results and theoretical design results were compared to confirm the simulation model. Based on the confirmed simulation
model, the simulation results of pressure and flow of the hydraulic system were analyzed. The dynamic simulation method is
very helpful for designing and analyzing the performance of hydraulic system and further optimization design. The theoretical
design method and dynamic simulation model are feasible for the real industrial applications. The research results can be
used in hydraulic system design and optimization.
Foundation item: Project(911901204) supported by Youth Innovation Foundation of Beijing University of Aeronautics and Astronautics 相似文献
994.
脉冲清灰是袋式除尘器的过滤再生循环过程,相关的流场分布特性直接影响其清灰性能。针对清灰过程喷吹时间短、速度变化快的特点,建立相应的质量通量方程及非稳态流场模型。通过改变喷嘴结构及喷吹控制参数,采用数值模拟方法获得各种条件下的压力、速度分布云图。实际应用表明:基于数值模拟探讨影响清灰效果的因素及其规律,可为袋式除尘器喷吹清灰的优化设计提供重要参考。 相似文献
995.
Non-contact atomic force microscopy(nc-AFM) atomic-scale imaging process of monocrystalline silicon surface using capped single-wall carbon nanotube tip is simulated by molecular dynamic method. The simulation results show that the nc-AFM imaging force mainly comes from the C-Si and C-C chemical covalent bonding forces, especially the former, the nonbonding Van der Waals force change is small during the range of stable imaging height. When the tip-surface distance is smaller than the stable imaging height, several neighboring carbon atoms at the tip apex are attracted, and some of them jump onto the sample surface. Finally the tip apex configuration is destroyed with the tip indenting further. 相似文献
996.
To investigate the influence of design parameters on the performance of separation device,the structure and air-operated test of a low-shock separation device are introduced and analyzed in this paper.According to the law of energy conservation and aerodynamics,a mathematical model is built.Because the preload used to ensure the connection reliability has the discreteness,which will influence the separation process,the influence of preload discreteness on the air-operated separation process is simulated and tested.Simulation results are consistent with the experimental results.It is shown that the change of preload has an obvious influence on the separation process.The study is useful for the design and optimization of separation device. 相似文献
997.
998.
A similar material model and a numerical simulation were constructed and are described herein. The deformation and failure of surrounding rock of broken and soft roadway are studied by using these models. The deformation of the roof and floor, the relative deformation of the two sides and the deformation of the deep surrounding rock are predicted using the model. Measurements in a working mine are compared to the results of the models. The results show that the surrounding rock shows clear rheological features under high stress conditions. Deformation is unequally distributed across the whole section. The surrounding rock exhibited three deformation stages: displacement caused by stress concentration, rheological displacement after the digging effects had stabilized and displacement caused by supporting pressure of the roadway. Floor heave was serious, accounting for 65% of the total deformation of the roof and floor. Floor heave is the main reason for failure of the surrounding rock. The reasons for deformation of the surrounding rock are discussed based on the similar material and numerical simulations. 相似文献
999.
Overburden rock movements and fracture developments occur during mining activities. Consequently, relief gas reservoirs and migration in coal seams being mined as well as in near distant coal seams appear. We considered a gas disaster management project and rules on stope relief of gas flows together and explored a gas reservoir and the evolution of stope surrounding rock fractures in the process of mining near distant protective layers by physical simulation, numerical simulation and field testing. Different techniques provide evidence of the rules of interaction of gas reservoirs and the evolution of surrounding rock fractures and are able to find accurately the gas-rich regions around the stope. Finally, we found that these rules can provide a basis for taking measures to prevent gas accidents in the protective layer of the coalface as well as for demonstrating and designing programs to drain high concentrations of gas from the gob. 相似文献
1000.
郭昆丽 《陕西科技大学学报》2009,27(3):125-129
建立了VSC-HVDC系统的数学模型,基于鲁棒控制理论,将系统对VSC-HVDC的控制目标转化为对其交流侧有功和无功电流的控制来实现,并进行了控制方案设计.仿真实验表明所设计的控制器能够快速反应达到预定的指令目标,具有良好的鲁棒性. 相似文献