自由旋转粘度计的研究与设计

给出一种借助单片机与FPGA/CPLD技术的自由旋转粘度计设方方法.自由旋转粘度计首先将流体粘度转换成转子的角位移信号,然后通过编码盘将角位移转移为测量脉冲,其后采用FPGA精确测量其脉冲参数,最终获取粘度测量结果.详细介绍了自由旋转粘度计的基本结构与工作原理,并对测量误差进行了简单分析,同时介绍了基于FPGA技术进行角位移测量的详细设计方法.该粘度计可以在很低的转速、很短的时间测得流体的粘度,这对于提高测量精度是非常有效的.     

一种带有粘温转换功能的新型旋转粘度计的设计

为测得不同温度下和剪切率下的牛顿液体粘度,利用液体粘度与温度的关系,设计了一基于单筒旋转粘度计的带有粘温转换功能的新型旋转粘度计,解决了对于需要测得不同温度下的液体粘度的难题.该仪器以PIC18F877单片机为核心,利用定时/计数器(Timer0)模块进行角位移测量,通过程序中的粘温转换算法,实现了粘度测量和粘温转换功能.测试证明,该新型粘度计能够满足实际应用要求.     

吊丝旋转粘度计

粘度是冶金熔渣、熔融硅酸盐等熔体的一个重要物理化学性质。粘度的研究具有十分重要的意义。目前,国内外广泛采用的是内圆柱体旋转法。其特点是适应于变化范围较大的熔体粘度的测量,但其缺点是测量精度较低,内圆柱体旋转时摆动产生测量偏差等等。这种落后的方法与工业发展是不相适应的。为了开展炉渣粘度研究工作,我们研制了一台具有光电脉冲数字显示记录系统的吊丝旋转粘度计。一、原理本装置属于内圆柱体旋转粘度计,所谓     

粘度测定原理与应用

粘度的测量在石油、化工、国防，医学等行业起着越来越重要的作用，我们在测量流体粘度时必须了解不同粘度的测量原理和它们的适应范围，选择合适的粘度计，本文主要分析粘度测量中常用的细管法、落体法和旋转法的以及采用此方法粘度计的应用场合。     

直击现场

<正> 全球科学服务领域的领导者赛默飞世尔科技公司在2010年3月23～26日德国慕尼黑举办的国际实验室技术、分析与生化博览会(Analytica 2010)上,公开展示各种流变特性和粘度测定产品组合。目前,Thermo Scientific粘度计与流变仪在全球实验室中享有盛誉,被广泛应用于各种场合。Thermo Scientific HAAKE Viscotester 550旋转粘度计可简单、快速、精确地测量液态和半固态测试材料的粘度与流动特性,如土壤、油漆、     

卧式旋转圆筒粘度计的测试原理

卧式旋转圆筒粘度计是一种新型的粘度计。它不同于常见的直立式旋转圆筒粘度计,在结构、测试原理、测试方法等方面都有它自己的特点。本文简单地介绍了卧式旋转圆筒粘度计的结构;从牛顿内摩擦定律出发,讨论了流体在旋转圆筒间的动平衡流动;讨论了它的流速表达式、粘度表达式、流变方程;简要地介绍了宾汉流体和幂律流体的相应表达式;最后简述了这种粘度计的优点。     

NXS—11型实验室旋转粘度计

“粘度”是一个重要的物理参数,常用来表示流体物质的流动性和粘滞性。而粘度计又是用来检定流体产品质量必不可少的仪器,如测定润滑油的粘度,就需要使用粘度计。NXS—11型实验室旋转粘度计是一种通用性较强的上旋式粘度计,它适用于工矿企业和科研部门的实验室对各种流体物质进行常规粘度的精密测量,也可以测定各种非牛     

微型粘度计

英国研制出一种能自动重复测量低粘度液体粘度的粘度计。它所用的液体试样只要60毫升就足够了。这是一种微型落球或自动粘度计,液体的粘度与球体在圆筒形管内     

NXS-11型旋转粘度计的研制

一、概述“粘度”是一个重要的物理参数,表示液体内部阻碍其相对流动的特性。它是液体中液体分子之间、固体颗粒之间及液体分子与固体颗粒之间内摩擦的结果。不同类型的液体有不同的粘度。NXS-11型旋转粘度计是一种通用性较强的粘度计,适用于工矿企业和科研部门实验室对各类液体作常规粘度精密测量,也可以测定     

毛细管校正系数简易测定法

毛细管较正系数又称粘度计常数,测定油品运动粘度用的平氏毛细管,其常数应由检量单位测得,新购置的运动粘度仪,都附带有一组(内径从0.4～4.0毫米,共11支)已知常数的毛细管。在测定粘度过程中,由于毛细管容易折断(特别是弯管部位),需要不断补充未知常数的毛细管,为了较迅速地测出未知常数,我们拟定了一个简易的测定方法,经对0.8毫     

Measurements of blood viscosity using a pressure-scanning slit viscometer

A newly designed pressure-scanning slit viscometer is developed to combine an optical device without refraction while measuring blood viscosity over a range of shear rates. The capillary tube in a previously designed capillary viscometer was replaced with a transparent slit, which is affordable to mount optical measurement of flowing blood cells. Using a pressure transducer, we measured the change of pressure in a collecting chamber with respect to the time, p(t), from which the viscosity and shear rate were mathematically calculated. For water, standard oil and whole blood, excellent agreement was found between the results from the pressure-scanning slit viscometer and those from a commercially available rotating viscometer. This new viscometer overcomes the drawbacks of the previously designed capillary viscometer in the measuring whole blood viscosity. First, the pressure-scanning slit viscometer can combine an optical instrument such as a microscope. Second, this design is low cost and simple (i.e., ease of operation, no moving parts, and disposable).     

On-line acoustic viscometry in oil condition monitoring

The paper describes the theoretical standpoints of developing magnetoelastic viscometers and a concept of viscosity measurement. The magnetoelastic viscometer has shown the readings close to the capillary viscometer. Testing of the oils with PMMA viscosity-index improvers by viscometers has indicated changes in rheological properties observed in the non-Newtonian behavior of the oils. With increase in content or molecular weight of the improver, the non-Newtonian behavior of the oil appeared at lower frequencies of viscosity measurements.     

SVM3000斯塔宾格黏度计测定液体石油产品的运动黏度

利用奥地利Anton Paar公司生产的SVM 3000斯塔宾格黏度计（Stabinger viscometer）测定了基础油、润滑油、燃料油和原油等透明和不透明石油产品的运动黏度。对不同黏度等级基础油的重复测定结果符合ASTM D7042规定的重复性限要求,三个实验室对润滑油、燃料油和原油的测定结果相对标准偏差在1％以下。分别用斯塔宾格黏度计和毛细管黏度计测定了多种基础油的运动黏度,结果表明两种方法测定40℃运动黏度的结果相关性为Y＝0.9995 X （Y 为斯塔宾格黏度计的测定结果,X为毛细管黏度计的测定结果）,100℃运动黏度的结果相关性为Y＝1.0033 X ,说明两种方法的测定结果一致,无显著性差异。     

Blood viscosity measurements using a pressure-scanning capillary viscometer

A previously designed capillary viscometer with measuring differential pressure was modified to measure the viscosity of non-Newtonian fluids including unadulterated blood continuously over numerous shear rates in a single measurement. Because of unavoidable experimental noise and a limited number of data, the previous capillary viscometer experienced an inaccuracy and could not directly determine a viscosity without an iterative calculation. However, in the present measurement there are numerous data available near the point of interest so that the numeric-value of the derivative,d(lnQ)/dln τω), is no longer sensitive to the method of differentiation. In addition, relatively low and wide shear rate viscosity measurements were possible because of the present precision pressure-scanning method with respect to time. For aqueous polymer solutions, excellent agreement was found between the results from the pressure-scanning capillary viscometer and those from a commercially available rotating viscometer. In addition, the pressure-scanning capillary viscometer measured the viscosity of unadulterated whole blood without adding any anticoagulants.     

Measurement of the viscosity of biodiesel by using an optical viscometer

In this paper, we report the characterization of the viscosity of biodiesel produced from jatropha curcas. The viscosity measurement has been carried out by using a modified falling ball viscometer as well as optical technology. The viscosity was measured from 28 to 70 °C, which is the interest for determining the quality of biodiesel. We found that the falling ball optical viscometer offers a resolution of a viscosity measurement of ±0.039 mPa s with a relative error of 1.47933%. The measurement process was compared with a commercial viscometer, and it has been demonstrated that the biodiesel produced in Chiapas has good quality.     

A magnetoelastic viscometer for on-line monitoring of viscosity of lubricating oils

The paper discusses the prospects for developing means for on-line measurement of the viscosity of lubricating oils, including diagnostic instrumentation based on magnetoelastic interaction. The theoretical basis for the development of magnetoelastic sensors and the main concept of measuring the fluid viscosity are presented. Two methods of measuring the viscosity are described. The first method is based on estimating variations in the natural frequency of oscillations of a sensitive element and the second involves analysis of the decay rate of the amplitude of oscillations. The design of the developed magnetoelastic sensor and the experimental results of comparing the two measurement methods are reported. The paper also presents the comparative results of measurement of the oil viscosity by a magnetoelastic sensor, a capillary viscometer, and a solid-state piezoacoustic sensor. It is shown that the reliability of the magnetoelastic sensor is high from the viewpoint of on-line monitoring; owing to its relatively low cost and ease of maintenance, it has wide potential for application in monitoring of lubricating oils in tribosystems.     

In situ Measurement of Journal Bearing Lubricant Viscosity by Means of a Novel Ultrasonic Measurement Technique Using Matching Layer

An ultrasonic viscometer was used to measure the circumferential viscosity variation in a journal bearing noninvasively. This sensing technique is based on the reflection of a shear wave at a solid–liquid boundary that depends on the viscosity of the liquid and the acoustic properties of the solid. Very little ultrasonic energy can propagate into the oil at a metal–oil interface because the acoustic mismatch is significant. Interleaving a matching layer between the metal and the lubricant enables accurate ultrasonic viscosity measurements (M. Schirru, et al., Tribology Leters, Vol. 60, No. 3, 2015). This technique has been used to build a miniaturized ultrasonic viscometer that is accommodated inside a journal to obtain the circumferential viscosity profile. Four viscosity regions are identified due to the variations in the localized temperatures and loads. The results are compared with the isothermal solution of the Reynolds equations for hydrodynamic lubricated bearings. The ultrasonic viscometer locates the angle at which the maximum load occurs and the length of the loaded contact with good accuracy. Finally, the viscosity results are used to estimate the frictional power losses. It is shown that over 70% of the total losses in the journal bearing occur in the region where the load is maximum.     

Rheological properties of high‐viscosity‐index mineral base oils for automotive engine lubricants

Viscosity‐pressure‐temperature relations for paraffinic mineral base oils at pressures up to 0.7 GPa and temperatures between 30 and 90°C were determined using a falling‐ball‐type viscometer. The oils used were solvent refined oils, hydrocracked oils, and an oil produced by a wax isomerisation process. The viscosity at pressures higher than those possible with the viscometer was then derived by applying a simplified solution to the traction curves determined using an elastohydrodynamic disc‐on‐ball tester. When the measured viscosity and the calculated viscosity were plotted against pressure, for the oils with a viscosity index higher than 120 the viscosity derived from traction measurements followed the curve extrapolated to the high‐pressure region using either the Yasutomi or Roelands equations (the parameters for which were obtained using the viscometer). However, the calculated viscosity for the lower‐viscosity‐index oils deviated upwards from the extrapolated curve.     

气油两相流粘度特性的试验研究

建立了一台实用的旋转式气油两相流粘度测试装置。在此装置上试验研究了容积气体体积分数、油膜厚度、以及切应变速率等因素对气油两相流粘度特性的影响。归纳出气油两相流粘度特性的一般表达式为：在改装后的ＭＰＶ－１５００试验机上，试验证明了在高剪切速率下，该一般表达式仍然成立。     

The High-Pressure Rheology of a Soap-Thickened Grease

The high-pressure rheology of a soap-thickened grease and the base oil has been characterized using a falling-body viscometer, high-pressure Couette viscometer, and a high-pressure penetrometer. At shear stress from 0.1 to 1 MPa, the response of the grease was approximately linear with rate of shear with a viscosity about twice that of the base oil. Apparent yield stress behavior is observed at lower shear stress. A new modified Bingham model is offered to describe the experimental observations. These results are relevant for simulations of elastohydrodynamic lubrication and journal bearings operating at elevated ambient pressure.