高温高剪切条件下润滑油粘度测定新技术

本文介绍润滑油在高温高剪切条件下测定粘度的方法及国内相关仪器动态,应用CANNON HTHS-1F高温高剪切粘度仪对润滑油进行测定并对结果进行总结。     

基于变粘度条件的流体静压支承摩擦转矩的研究

在研究圆形静压支承中,如果考虑到粘度随温度变化的特性,则与油膜厚度相关的摩擦转矩关系曲线不再是粘度为常数时的双曲线,这时曲线的形状发生了明显的变化。本文对油膜厚度和摩擦转矩的关系进行了深入的理论分析,从而揭示了其本质规律,为设计出结构合理、性能优良的静压支承提供了理论依据。     

考虑热效应影响的液黏调速离合器流体剪切转矩预测研究

为了更准确地对液黏调速离合器流体剪切转矩进行预测,以液黏调速离合器摩擦副间的流体为研究对象,建立了考虑热效应影响的三维CFD模型,并考虑了黏温特性的影响,应用计算流体力学软件CFD ACE+对流场进行求解,得到了摩擦副间流体的压力和温度分布以及流体剪切转矩的数值解;通过实验研究对比分析了不同转速和油膜厚度下的流体剪切转矩。结果表明：影响温度分布的主要因素是流体剪切线速度;热效应对摩擦副间流体的压力分布有较小的影响;由于流体温度对黏度的影响,流体剪切转矩随着转速差的增加而缓慢增大。因此,通过与实验数据对比分析,考虑热效应影响的三维CFD模型能够更为准确地对转矩进行预测。     

流体粘度的微观表达

应用相关函数理论及流体分子在微观状态下的力学表现 ,推导出流体在微观状态下的粘度表达式 ,对理解粘度与流体运动状态的关系及流体润滑轴承具有重要意义 ,特别是对解释超薄膜润滑状态下流体膜的形成及计算 ,对流体力学性质的模拟提供理论依据     

流体密封的磁流变流体粘度特性分析

叙述了流体密封中磁流变流体(Magnetorbelogical Fluid，简称MRF)的磁变效应。介绍了纳米Fe3O4磁流变流体的粘度特性实验，并对磁流变流体的粘度特性进行分析。为磁流变流体在流体密封中的应用提供参考依据。     

测量流体传输管道内压力脉动的新方法

流体传输管道内的压力脉动反映了流体动态流动的基本特性。准确可靠地测量压力脉动,对流体脉动的理论和试验研究都是非常重要的。本文介绍了作者近年来采用的管内压力脉动测试的新方法及应用实例,如无损管壁测压装置、计算机在线检测和处理等先进技术的应用。     

剪切间隙条件下铝合金板材剪切力学性能的研究

通过自行设计制造剪切装置,研究剪切速率对5052-H32、6061-T6、7075-T651三类铝合金板材力学性能的影响.实验结果表明:剪切速率对铝合金板材的剪切强度影响程度中,对6061-T 6的影响幅度最小(2.6％ 以内),7075-T651次之,5052-H32最大;在厚度为2 mm、4 mm和6 mm的三类板...     

基于电磁感应的液体粘度在线测量方法研究

在传统电磁流量计的基础上引入了层析成像技术,经理论分析后提出了一种非侵入、可在线测量牛顿流体及非牛顿流体粘度的新方法.通过对不同流体各类流变参数下的数值实验、仿真研究和误差分析,证明方法能有效地应用于流体粘度的在线测量,克服了离线分析法或侵入式测量法无法同时满足在线和非侵入的测量要求,具有较好的应用前景.     

测试数控锻压机械用伺服电机工作特性的一种新方法

本文论述了当前锻压行业先进机型数控伺服挤压机的伺服电机选型的若干重要问题，提出了通过伺服电机转矩测量挤压机实际工作压力的一种新方法，并以实际测量数据对如何充分利用伺服电机工作能力作了阐述，为配置高性价比的数控挤压机的伺服驱动系统提供了依据。     

磁流变液的流变性试验研究

磁流变液是一种新兴的智能材料,以其优良的物理特性、力学特性和可控性,广泛应用于工程领域。文中采用试验的方法对不同的磁场强度、不同的剪切速率以及不同的铁粉质量分数的百分比下的流变性进行研究,得到了磁流变液材料的性能随磁场强度、剪切速率、铁粉质量分数的百分比等变化的规律,为磁流变材料的开发研究和工程应用提供了基本依据。     

精确测量微量液体折射率的新方法

介绍了一种用玻璃毛细管精确测量微量液体折射率的新方法.该方法基于共轴球面光学系统的成像原理,通过读数显微镜对吸入待测液体后毛细管的焦点位置进行单一参数的测量,进而计算出待测液体的折射率.用此方法测量了纯水、乙醇、乙二醇、丙三醇的折射率,各种待测样品的需要量＜0.002 ml;测量结果表明,纯水和乙醇样品的折射率测量精度优于0.000 3;乙二醇和丙三醇样品的折射率测量精度优于0.000 7.选用适当的毛细管参数,可以进一步提高这种测量方法的测量精度,扩展折射率的测量范围.分析和讨论了实验测量误差以及进一步提高测量精度的方法.该方法具有待测液体用量极少、使用设备简单、操作方便和折射率测量精度高的特点.     

New method for measuring the thermal conductivity

A new experimental method is presented for measuring the thermal conductivity as a function of temperature. The basic innovation lies in extracting from the measured temperature profile of a sample in vacuo, the thermal conductivity of each individual cross-sectional sample element. The estimated experimental error is +/-1%. Not only is high accuracy achieved, but also a self-checking procedure offers the possibility of avoiding systematic errors. Measurements on two samples of type 304 stainless steel are presented. Three independent sets of measurements give consistent values for the thermal conductivity to well within the estimated error of +/-1%.     

一种精确测量微量液体折射率的新方法

摘 要：本文介绍了一种用玻璃毛细管精确测量微量液体折射率的新方法。这种方法基于共轴球面光学系统的成像原理,通过读数显微镜对吸入待测液体后毛细管的焦点位置进行单一参数的测量,进而计算出待测液体的折射率。用此方法测量了纯水、乙醇、乙二醇、丙三醇的折射率,各种待测样品的需要量小于0.002 ml;对纯水和乙醇样品,折射率测量精度优于0.0003;对乙二醇和丙三醇样品,折射率测量精度优于0.0007。选用适当的毛细管参数,可以进一步提高这种测量方法的测量精度,扩展折射率的测量范围。该方法具有待测液体用量极少、使用的设备简单、操作方便和折射率测量精度高的特点。论文对实验测量误差以及进一步提高测量精度作了详细的分析和讨论。     

液体表面张力激光快速测量法

基于插板法测液体表面张力系数的基本原理,介绍了一种利用半导体激光器及准直光学系统输出的矩形平行光束,结合线阵CCD传感器,实现液体表面张力系数快速测量的方法。通过测量激光束两边沿在液体表面的入射角来求得表面张力系数,解决了插板法测液体表面张力系数的液面上升高度和接触角检测难题,避免了人为因素的影响。推导了矩形激光束两边沿在液体弯月面的入射角与表面张力系数的关系,以及用CCD测量激光入射角的计算公式,并进行了参数设计和误差分析。结果表明:为了提高液体表面张力系数的测量精度,在满足测量条件下,应采用尽可能大的矩形激光束宽度、激光入射角和CCD相对距离。理论分析表明,当光束宽度的测量误差为5 μm时,水的表面张力系数测量精度为1%。若将光束宽度的测量误差减小到2 μm,则水的表面张力系数理论精度可达0.5%。实验结果证明了水的表面张力系数测量精度达到1%。     

New test method and apparatus for measuring galling resistance

Galling is a severe type of wear that can occur when relative motion exists between contacting surfaces. It is characterized by surface protrusions and an increase in surface roughness of one or both components. Galling can occur vary rapidly; under certain mating conditions it can occur in as little as one cycle and can even lead to the eventual seizure of mating components. In this study, a new test method and apparatus for measuring the galling resistance of mated materials was developed. Tests were conducted on self-mated stainless steel to determine the threshold galling stress. The new test method requires the use of two specimens, namely a stationary button and a rotating cylinder. The end of the stationary button contacted the rotating cylinder along the cylinder's length, thereby creating line contact. Galling occurred along the line of contact when the cylinder was rotated and the load between the specimens was increased. The threshold galling stress was calculated using force measurements from a load cell on the stationary button. In addition to measuring the force between the specimens, the torque required to rotate the cylindrical specimen was measured in order to determine the frictional force between the cylinder and button.     

New device and method for measuring thermal conductivity of thin-films

Thermal sensitive paints (TSPs) are used for global nonintrusive detection of boundary layer transition in flow over the surface of wind tunnel research models. Since the transition is a transient process, the TSP should have a fast response characteristic. A low paint thermal conductivity is required for fast response. A thin-film thermal conductivity meter (TFTCM) was designed and built to measure thermal conductivity of the TSPs, which are typically between 50 and 150 microm thick. In this paper, the design and operating features of the TFTCM are described. Measurement of the thermal conductivity with this TFTCM of three standard thin-film low conductivity specimens, Kapton, Teflon, and Borofloat glass, showed good agreement with the manufacturer quoted values, thus validating the instrument and the procedure. Consistently repeatable values for thermal conductivity (k=0.41 +/- 0.02 W/m K) were also obtained for the TSP specimen (TSB-B, 75 microm) tested.     

采用科里奥利质量流量计的流体黏度测量方法及装置设计

通过对弯曲振动运动进行分析,并结合流体运动及内摩擦力耗能情况,提出了一种新的黏度检测方法,导出了流体动力黏度与科里奥利质量流量计振动参数的关系,通过实验验证了方法的正确性.采用FPGA为主要器件,构成了黏度测量装置.该方法简单、实用,拓展了科氏流量计的应用领域,为其增加了一种新的功能.     

An automated setup for measuring the viscosity of metal melts

An automated setup for measuring the kinematic viscosity of metal melts using the method of damped torsional oscillations is described. The experimental errors in the viscosity determination are evaluated. The influence of the values of the damping factor, the oscillation period, and the sample radius and height on the value of the calculated viscosity error is analyzed. The methodological errors that are related to the consideration of the free-surface curvature, the thermal expansion, and the external friction in the inert atmosphere of the suspension system were analyzed. It is shown that these errors may have a significant effect on the viscosity determination accuracy. The viscosity of liquid lead in the range from the melting point to 1200°C is determined. The obtained data agree well with the literature data.     

A simple instrument for measuring the surface tension and viscosity of liquids

The surface tension and viscosity of liquids are usually measured using different instruments, which increases the measurement time. This time is often too long for certain biological liquids and solutions. The instrument proposed allows both quantities to be measured quickly with fewer manipulations of the liquid.__________Translated from Pribory i Tekhnika Eksperimenta, No. 2, 2005, pp. 144–145.Original Russian Text Copyright © 2005 by Man Singh.