钢渣在流化床中碳酸盐化的数值模拟

文章采用数值模拟的方法来模拟钢渣在流化床中的碳酸盐化反应。运用双流体模型来描述流化床中的气固两相流动。采用未反应核模型计算反应速率,扩散系数根据反应过程中颗粒孔隙结构的变化进行了相应的修正。通过UDF自定义程序导入化学反应速率,实现流化床内气固两相流动、传质和化学反应之间的耦合。模拟结果可知颗粒粒径、反应温度、吹气速度、CO_2浓度均对反应有一定的影响,缩小颗粒粒径,提高反应温度、吹气速度、CO_2浓度都可以提高反应效率,其中CO_2浓度对反应速度影响较大。     

Numerical Simulation of Concrete Plate Damaged Under Explosive Loading

The grisliness after-effects can be induced by explosion accident with the collapsing of the structures, the demolishing of the equipments and the casualty of the human beings. Isolation belt constructed between the blast point and the construction is one of the useful design schemes for blast resistance. The nonlinear procedure ANSYS/LSDYNA970 is used to simulate the contact detonation and the isolation belt of blast resistance filled with the air or water respectively. The results indicate that the maximal damage can be caused by the contact detonation, and the isolation belt of blast resistent filled with water can reduce the damage greatly.     

基于数据融合与互相关技术的气固两相流固相流速测量技术研究

将信息处理技术引用到气固两相流参数检测中,初步探讨了应用数据融合技术及互相关技术进行固相颗粒界面平均速度的检测。采用两种方案确定上、下游传感器渡越时间,包括每对传感器采集的数据先进行互相关分析再进行数据加权融合,以及对所有传感器采集的数据先进行融合处理,再对其进行相关分析。通过对这两种信息处理方案进行仿真研究,得到稳定且正确的仿真结果。     

Numerical and experimental investigations of human swimming motions

This paper reviews unsteady flow conditions in human swimming and identifies the limitations and future potential of the current methods of analysing unsteady flow. The capability of computational fluid dynamics (CFD) has been extended from approaches assuming steady-state conditions to consideration of unsteady/transient conditions associated with the body motion of a swimmer. However, to predict hydrodynamic forces and the swimmer’s potential speeds accurately, more robust and efficient numerical methods are necessary, coupled with validation procedures, requiring detailed experimental data reflecting local flow. Experimental data obtained by particle image velocimetry (PIV) in this area are limited, because at present observations are restricted to a two-dimensional 1.0 m² area, though this could be improved if the output range of the associated laser sheet increased. Simulations of human swimming are expected to improve competitive swimming, and our review has identified two important advances relating to understanding the flow conditions affecting performance in front crawl swimming: one is a mechanism for generating unsteady fluid forces, and the other is a theory relating to increased speed and efficiency.     

热泵/制冷循环模拟实验台的设计

运用世纪星组态软件设计了热泵/制冷循环演示模拟实验台,可以动画演示整个实验过程,可以更直观地看到各种实验现象,并能通过热力计算随时了解系统的性能,显著提高了实验教学的效果。     

基于多体系统理论的机床运动学仿真与应用研究

从多体系统运动学理论的角度, 构建了机床各部件之间的拓扑结构和约束关系, 建立了三维多体模型, 开发了运动学仿真系统. 设计者可在虚拟环境下观察到整个机床的运动加工过程, 准确了解零部件的位置、速度和加速度等运动参数, 判断零部件的姿态, 并可在样机试制前对设计中可能出现的问题作出精确的预测和改进, 保证设计方案的可行性, 缩短产品的研制周期和降低成本. 该仿真系统用于CK1416高速高精度数控车床的设计, 所得到的滚珠丝杆角速度曲线、拖板位移曲线与理论结果一致, 从而证明了模型的正确性.     

自由圆管在横向冲击载荷下的动力学行为研究

对自由圆管在其中心部位经受刚性平头弹体横向冲击时的动力学行为进行了实验研究和计算机仿真.研究了不同管径、管长以及不同材质的自由圆管在3种不同直径和质量的平头弹体的横向冲击下的变形历程、最终的变形模态以及能量的分配方式,得到了自由圆管被穿透时子弹的临界速度和临界动能.并把实验和模拟的结果与自由梁模型的情况作了比较和分析.     

IFS分形图的透视变换模拟

在给定IFS码的基础上,应用透视变换的方法将三维空间上的分形投影到二维屏幕上加以显示,并通过参数调整产生大量具有特殊视觉效果的分形图,研究了参数变化时分形图的演化.     

Simulation study on fluctuant flow stress scale effect

INTRODUCTION With the continuous development of science and technology, especially the rapid progress of electronic industry and micromachine, microparts are needed more and more, and their technical requirements are higher and higher (Geiger et al., 1994; 1996; Geiger and Engel, 2002). However, traditional processing technologies, like cutting, etc., do not meet these requirements. Traditional plastic forming technology has merits like high production rate, excellent me-chanical proper…     

基于VHDL的数字计时器的设计

文章论述了数字计时器的设计原理、设计步骤以及用VHDL语言设计数字计时器的方法。数字计时器的设计主体是计数部分和译码部分,仿真结果表明,设计的计时器精度高。