节流口内空化流体的湍动特性

为了提高孔板空化器的水力空化强度并得到空化规律,考虑到脉动对空化模型的影响引入了脉动影响因子,得出流体脉动空化模型,采用多相流的方法通过Fluent软件得出流体的气液两相传质速率及湍流强度,最后得出流体空化规律.研究结果表明:当恢复压力一定时,适当增加入口压力可以提高流体的空化强度,在0.5～0.7 MPa可获得较大的空化强度,当压力继续增加时,使空化强度和发育程度均降低;相比于进口压力,出口压力对流体空化强度起主导作用,在0.4～0.6 MPa空化强度不断增强,当出口压力继续增加时,压差过小抑制了空化的发生;分析多孔出流的流体湍动模型和传质速率得出,在0.4～0.6 MPa多孔出流引起了流体的湍动叠加效应,导致空化强度增加.     

环形橡胶径向刚度特性仿真分析

利用ANSYS软件建立了环形橡胶的有限元参数化模型,将对模型仿真所得结果与已有数据进行对比,验证了仿真模型的正确性,实现了环形橡胶径向刚度的快速计算.在此基础上,分析了内外圆柱面半径与轴向长度对环形橡胶简化径向刚度值的影响,研究了环形橡胶的径向刚度特性,确立了在环形橡胶实际设计中需要考虑的要点,为环形橡胶的设计提供了依据.     

四种油腔形状重型静压轴承承载性能理论分析

重型静压轴承承载能力是体现其性能优劣的一个重要指标.针对油腔形状对重型静压轴承承载能力的影响问题,利用有限体积法,模拟了矩形、扇形、椭圆形和工字形油腔间隙油膜的压力场,探讨了在转速、腔深及油腔面积相同时四种腔形的压力分布规律,优化了油腔结构.结果表明:四种油腔形状的静压轴承间隙油膜压力分布规律基本相同,但其承载能力不同,承载能力由大到小分别是椭圆形腔、扇形腔、矩形腔和工字形腔.仿真结果与理论分析具有较好的一致性,为实际生产中静压轴承油腔形状的选择提供了有价值的理论依据.     

Influence of load capacity on hydrostatic journal support deformation in finite element calculation

Based on the application of the four-oil-pad radial hydrostatic bearing in heavy equipments, the deformation of the four-oil-pad radial hydrostatic bearing was calculated by using the finite element method. The formula of film stiffness, film thickness and carrying capacity were established; the influence of the main parameters, such as load, load area and deformation on the supportability was analyzed; and the capacity of the two kinds of bearings was compared. The result shows that the carrying capacity of typeⅠ is prior to that of type Ⅱ . Calculations provide a theoretical basis for the bearing choosing and structure designing in the actual project.     

不同腔形结构静压轴承油膜温升特性对比分析

静压轴承间隙润滑油膜的温升是导致轴承本体变形的主要因素,为了探究不同腔形结构下静压轴承油膜温升特性,对工程实际应用较广泛的扇形油腔、椭圆形腔、矩形油腔、工字形油腔四种腔形结构静压轴承油膜温度场数值计算,并对相同工况条件下等腔面积的四种腔形结构静压油膜温升特性进行了对比分析。结果表明:矩形腔和扇形腔静压推力轴承油膜温度场分布情况相似,与椭圆形和工字形腔不同,温升由高到低依次为工字形腔、椭圆形腔、扇形腔和矩形腔。该研究结果可为静压轴承热变形预测提供理论依据,并为工程中油腔结构设计提供参考。     

动力减振镗杆中环形橡胶径向刚度有限元分析

基于弹性力学经典理论,给出了内藏式动力减振镗杆中环形橡胶径向刚度的计算公式.建立了基于ANSYS的环形橡胶有限元模型,通过模型分析的结果与理论值的对比,验证了有限元模型及其分析结果的正确性.最后利用ANSYS中的优化分析功能,实现了环形橡胶径向刚度与其他参数之间的快速而准确的换算.     

大尺寸扇形静压推力轴承润滑性能的数值分析

针对重型装备中所应用的大尺寸工作台静压推力轴承的润滑问题进行了研究,建立了模拟静压轴承本体及导轨内部三维流动的数学模型及边界条件,并利用CFD(Computational Fluid Dynamic)原理,采用FLUENT软件和有限体积法对扇形腔的静压轴承内部流体压力场及速度场进行了仿真和计算,得到了静压轴承内部的流速及压力分布.通过该仿真程序可以模拟出不同参数下静压轴承的润滑性能,可提前实现对大尺寸静压轴承润滑的特性的预测.     

一种具有低截获特性的组合调制雷达信号

针对雷达在现代电子战争中采用简单调制的电磁波信号容易被远距离的敌方电子侦察设备截获的问题,提出了一种线性调频和Taylor四相码的组合调制雷达信号,通过理论分析和计算机仿真,给出了信号的波形,画出了模糊图,分析了距离分辨力、速度分辨力和低截获特性,结果表明该信号具有线性调频和Taylor四相码2种信号的优点,是一种具有“图钉”型模糊函数的低截获概率信号．     

Simulation and experimental analysis of supporting characteristics of multiple oil pad hydrostatic bearing disk

To study the heavy hydrostatic bearing with multiple oil pads, a reasonably simplified model of the pad is put forward, and the mathematical model of the bearing characteristics of the multiple oil pad hydrostatic bearing is built with consideration of variable viscosity. The pressure field in the clearance oil film of the hydrostatic bearing at various velocities is simulated based on the Finite Volume Method (FVM) by using the software of Computational Fluid Dynamics (CFD). Some pressure experiments on the hydrostatic bearing were carried out and the results verified the rationality of the simplified model of the pad and the validity of the numerical simulation. It is concluded that the viscosity has a great influence on the pressure in the heavy hydrostatic bearing and cannot be neglected, especially, in cases of high rotating speed. The results of numerical calculations provide the internal flow states inside the bearing, which would help the design of the oil cavity structure of the bearing in engineering practice.     

应用平衡计分卡理论建立KPI体系的实践

介绍了平衡计分卡的应用情况,对应用平衡计分卡理论建立KPI(关键绩效指标)体系进行了理论解读,结合安阳钢铁股份有限公司的管理实践,具体阐述了建立KPI体系的流程、方法、步骤和作用。