Characteristics of hydrostatic bearing/seal parts for water hydraulic pumps and motors. Part 1: Experiment and theory

In this paper, the load-carrying capacity, power losses and stiffness of disk-type hydrostatic thrust bearings including the case of eccentric loading are discussed theoretically. The numerical analysis method is established based on a two-dimensional elastohydrostatic problem with an elastic deformation model, which is extended to adapt it for a non-axisymmetric load acting on the thrust bearing. The bearing is made of a combination of stainless steel/stainless steel and stainless steel/plastics. For the elastic materials, the maximum stiffness derived from, i.e., minimum film thickness is, larger than that of the rigid material in the range of a large ratio of pocket pressure and a hydrostatic balance ratio of over unity, which is defined as the ratio of the load to the maximum hydrostatic load-carrying capacity. The maximum load-carrying capacity and minimum power loss can exist in the domain of the hydrostatic balance ratio over unity for the case of the bearing consisting of elastic/rigid materials, in comparison with that composed of the same rigid materials. For the case of water, the power loss due to leakage flow is slightly larger but that due to frictional torque is much smaller than that in the case of hydraulic oil. Then, the total power loss is much smaller than that of hydraulic oil.     

椭圆封头水平接管部位应力分析和加强效果研究

针对椭圆封头水平接管部位的强度评定和加强效果研究,采用有限元法建立了接管部位的应力计算模型,运用ANASYS程序进行了应力计算,应用分析设计原理对接管部位的强度进行了强度评定,最后根据接管部位的应力分布特点,对接管部位的加强结构进行了设计。通过应力计算和强度分析可见,合理的加强后,接管部位的局部应力明显降低,加强效果显著,强度满足要求。     

长清模拟科威特油井灭火试验中的流体力学计算问题

根据当时灭火试验提供的数据和模拟灭火现场的具体条件,从流体力学理论的角度,计算出完成水压试验和最后灭火试验所需的基本参数,为试验圆满成功提供了理论依据。     

Numerical Study on the Effect of Cavitation on Flow and Diesel Fuel Atomization Characteristics

Computational fluid dynamics (CFD) models based on the turbulent mixture multiphase model were applied to consider the effect of cavitation on the spray of diesel fuel. The effects of injection pressure and length‐to‐width (L/W) ratio on the velocity distribution, cavitation number, discharged coefficient, and nozzle exit velocity were investigated and the performance of the model was compared with the experimental data. The results indicate that the cavitation generated in the nozzle has a strong impact on the fuel injection and spray quality, whereas the L/W ratio is a highly effective parameter for cavitation behavior. In addition, by increasing the L/W ratio, the range of cavitation number, wall friction, and flow resistance increase but in the cavitation region the velocity profile in radial and axial directions, spray cone angle, nozzle exit velocity, and the discharged coefficient decrease.     

锅炉汽包接管断裂失效分析

对汽包上连接安全阀管路接管的断裂失效原因进行了综合分析 ,在排除了可能引发事故的诸多因素之后 ,找出了断裂发生的根本原因是由于安全阀排气管路的出口方向在设计上是不合理的 ,并提出了改进措施     

形状记忆合金在固定翼飞机上的应用探索

针对固定翼飞机存在的问题，科研人员将集传感器、驱动器和致动器于一身的形状记忆合金（Shape memory alloy，简称SMA）驱动器应用到飞机中，以改善飞行性能，抑制喷射噪音等。综述了SMA驱动的变形机翼、涡轮发动机进气道、喷口以及喷射噪音抑制装置的原理、结构和控制方法，并讨论了SMA在飞机上的应用。随着研究的不断深入，SMA必将在飞机上获得更为广泛的应用。     

可调式气体喷射器调节性能计算分析

提出在喷射器喷嘴内插入喷针来调节喷射器工作参数的方案,建立了可调式喷射器性能计算模型,计算分析了喷嘴截面积变化对喷射系数、气体压力、气体流量等参数的影响。结果表明,通过对喷射器喉口面积的调节,可拓宽喷射器的有效工作范围,减小喷射器入口参数对出口参数的影响。     

高压水除鳞喷嘴与射流特性的试验研究

在热轧板带生产尤其是薄板坯连铸连轧工艺中 ,除鳞是提高产品表面质量的关键工序之一 ,目前国内外普遍采用高压水除鳞技术。其中除鳞喷嘴的结构直接影响到射流的打击力及其分布形式 ,对除鳞效果起决定性作用。对高压水除鳞喷嘴的结构及其和水射流的特性之间的关系进行了大量的试验研究 ,总结出了射流散射角、喷射宽度方向特性、轴心打击力的变化规律 ,并对喷嘴结构参数的选择提出了见解。     

基于PLC的堵板密封装置控制系统设计

为保证核电厂反应堆压力容器与蒸汽发生器检修工作能够同时进行,需使用堵板密封装置对主管道进行封堵.这可以使得反应堆一回路水位的升降不影响蒸汽发生器的检修工作,同时也可保证人员和设备安全,避免人员或异物掉入主管道.使用西门子S7-1200 PLC作为控制器,采用全集成自动化博途软件进行编程设计.根据工艺流程,设计了可编程逻...