“流体传动与控制”双室联动教学方案的探索

为提升学生对“流体传动与控制”课程的学习质量,以重视产出式培养目标为导向,提出采用“教室+实验室”的双室联动教学方案,重视实验操作的规范性以及理论支撑的必要性,更重要的是锻炼学生将理论应用于实践、根据实践反向审视课堂理论知识的思维习惯,激发学生对本课程理论知识的学习热情,充分发挥学生的主观能动性。     

基于触摸屏的夹具磁性开关信号故障诊断方法

焊夹具是一种对白车身进行定位和固定的工装,主要由气缸、气管、阀岛、磁性开关、操作按钮盒等构成,在出现电气信号故障后因磁性开关数量多难以快速定位,导致维修处理时间长。基于这一问题,文章通过对夹具的控制方式和触摸屏的应用技术进行分析,设计一种能够将夹具磁性开关信号状态快速反映到人机界面（HMI）上的诊断方法,并在HMI上建立三维视图和状态图形,以此来快速诊断夹具的磁性开关信号故障,减少设备的停机时间,为生产效率提供必要的保障。     

微波能污水处理技术前景广阔

微波能污水处理技术改变了传统的污水处理方式,使污水处理方法变得更简易有效：其原理是微波对流体中的不同物质进行选择性分子加热;微波对流体中的吸波物质的物化反应具有强烈的催化作用;流体中的固相微粒在微波场中能迅速汇聚沉降与水分离;微波加热是吸波物质分子直接加热,所以废水置于微     

Green-Naghdi理论的全非线性浅水波数值模拟(英文)

Green-Naghdi (G-N) theory is a fully nonlinear theory for water waves. Some researchers call it a fully nonlinear Boussinesq model. Different degrees of complexity of G-N theory are distinguished by “levels” where the higher the level, the more complicated and presumably more accurate the theory is. In the research presented here a comparison was made between two different levels of G-N theory, specifically level II and level III G-N restricted theories. A linear analytical solution for level III G-N restricted theory was given. Waves on a planar beach and shoaling waves were both simulated with these two G-N theories. It was shown for the first time that level III G-N restricted theory can also be used to predict fluid velocity in shallow water. A level III G-N restricted theory is recommended instead of a level II G-N restricted theory when simulating fully nonlinear shallow water waves.     

二维水翼型空化流的数值计算(英文)

In order to predict the effects of cavitation on a hydrofoil, the state equations of the cavitation model were combined with a linear viscous turbulent method for mixed fluids in the computational fluid dynamics (CFD) software FLUENT to simulate steady cavitating flow. At a fixed attack angle, pressure distributions and volume fractions of vapor at different cavitation numbers were simulated, and the results on foil sections agreed well with experimental data. In addition, at the various cavitation numbers, the vapor fractions at different attack angles were also predicted. The vapor region moved towards the front of the airfoil and the length of the cavity grew with increased attack angle. The results show that this method of applying FLUENT to simulate cavitation is reliable.     

非结构化网格浸入边界法的流固耦合数值模拟(英文)

This paper presents an improved unstructured grid immersed boundary method. The advantages of both immersed boundary method and body fitted grids which are generated by unstructured grid technology are used to enhance the computation efficiency of fluid structure interaction in complex domain. The Navier-Stokes equation was discretized spacially with collocated finite volume method and Euler implicit method in time domain. The rigid body motion was simulated by immersed boundary method in which the fluid and rigid body interface interaction was dealt with VOS (volume of solid) method. A new VOS calculation method based on graph was presented in which both immersed boundary points and cross points were collected in arbitrary order to form a graph. The method is verified with flow past oscillating cylinder.     

液压软管应用于坚硬的凿石作业

在凿石作业中．振动、灰尘、湿度对机器及其组件的要求特别高。领先的工程机械制造商因此信赖ContiTech流体技术公司。这家活跃在全球的液压软管制造商,一直以来都在工地的日常恶劣工况作业中证明着自己的成功,并且不断根据新的要求继续发展。     

基于流体逼近的路段交通流动态加载研究

路段交通流动态加载是动态交通网络分配模型中的重要组成部分,在路段交通流动态加载中,离散形式或者连续形式的点排队模型被广泛使用.本文在以往研究的基础上,提出基于流体逼近的连续型点排队模型,克服了原有点排队模型中排队负值的情况.通过分析可以发现,原有点排队模型实质上属于具有单一服务台和无限容量的排队模型,基于流体逼近的思想重新定义了原有点排队模型.其中3 个主要部分是流量守恒模型,车辆流出模型和时间相关的服务台模型,这3 个模型全部都是连续的.由于连续点排队对计算需求较高,本文将连续的排队模型离散化,模拟了3 种不同场景下车辆驶出、路段排队情况.本文模型克服了原有点排队中的负排队现象,并且排队过程满足先进先出的原则,模型具有良好的模拟效果.     

圆形直管湍流粗糙管区的摩擦因数计算

提出了简单适用的管路摩擦因数λ的计算方法,解决了柯尔布鲁克-怀特(Colebrook-white)公式中隐函数不易计算的问题,该方法计算精度高于其他现有简化公式;在10-8≤ε/d≤0.05、3000≤Re≤108时,该方程的计算结果与原Colebrook-White方程的平均相对偏差为0.3315%,最大偏差不超过2.0%。     

管道内污水两相流的阻力计算

目前的污水管道设计是将污水在管道内的流动视为单相均匀流,主要用谢才(Chezy)公式进行水力计算。由于存在管线长、流量大以及区域地形变化幅度较大等因素,建设区域排水系统需要采用新的方法,以便较准确的计算水头损失。文中将污水视为液-固两相流体。对于沿程阻力的计算,将流体分为均质流与非均质流,分别给出沿程阻力系数的计算公式;对于局部阻力,则借用气-固两相流动的局部阻力系数计算公式。最后得出了两相流情况下与单相流情况下的阻力系数区别。结论是沿程阻力系数的区别可不计,局部阻力系数差别较大,在进行设计时必须考虑。