用黏度液黏温常数对旋转黏度计期间核查的探讨

本文介绍了一种在常温条件下,用精确而简便的方法核查旋转黏度计,利用现有的温度在20℃条件下定值的标准黏度液,常温再检测在该温度的运动粘度值,根据黏度液的黏温关系,确定并先后求得黏温常数B和A,最终判别旋转黏度计指示值,是否在允差范围自内。     

二级标准黏度液的研制

为了满足新疆地区对黏度标准物质的需求,研制了三种常用的标准黏度液。标准黏度液以精制甲基硅油为原料配制。使用MCR302流变仪分析甲基硅油的流动性和黏温性。使用标准毛细管黏度计对配制的黏度液进行均匀性、稳定性考察和定值,采用方差分析法和趋势分析法进行统计检验。评定了运动黏度值的不确定度并与国家一级标准物质比对,结果表明研制的黏度液量值准确可靠,相对扩展不确定度U=(0. 33～0. 40)%(k=2),均匀性和稳定性符合二级标准物质的要求,有效期1年,可以用于检定或校准工作用黏度计。     

油类与硅油型黏度标准液的量值差异

通过比较油类黏度标准液与硅油型黏度标准液在不同型号黏度计上的测量结果,以及两种黏度标准液的黏温特性、表面张力特性,探讨了油类黏度标准液与硅油型黏度标准液间的差异,为两种黏度标准液的实际使用提供参考。     

黏度标准物质研制

为满足液体黏度测量仪器量值溯源、黏度测量质量控制对黏度标准物质的需求,研制具有不同黏度水平的系列黏度标准物质.以精制甲基硅油为原料,采用哈克旋转流变仪、标准毛细管黏度计和基准恒温槽测试该系列标准物质的流动性、黏度、黏度-温度变化率以及表面张力,并对其均匀性、稳定性和不确定度进行检验和评定.实验结果表明:该系列黏度标准物质均匀性和稳定性良好,在(20±5)℃下可保存一年,相对扩展不确定度为0.24％～0.61％(k=2).通过与国家一级黏度标准物质量值比对,其定值结果的准确性达到国家二级标准物质的技术指标要求.该系列标准物质可用于黏度测试过程中的方法验证和检测结果质量控制等.     

黏度标准物质研制

为满足液体黏度测量仪器量值溯源、黏度测量质量控制对黏度标准物质的需求,研制具有不同黏度水平的系列黏度标准物质。以精制甲基硅油为原料,采用哈克旋转流变仪、标准毛细管黏度计和基准恒温槽测试该系列标准物质的流动性、黏度、黏度-温度变化率以及表面张力,并对其均匀性、稳定性和不确定度进行检验和评定。实验结果表明:该系列黏度标准物质均匀性和稳定性良好,在(20±5)℃下可保存一年,相对扩展不确定度为0.24%~0.61%(k=2)。通过与国家一级黏度标准物质量值比对,其定值结果的准确性达到国家二级标准物质的技术指标要求。该系列标准物质可用于黏度测试过程中的方法验证和检测结果质量控制等。     

多温度点黏度标准物质制备及定值技术

文章以加氢精制的石油产品为原料进行减压蒸馏制备标准物质候选物，分析候选物牛顿性、黏温性等，制得在20℃时标称值范围为(2～170) mm²·s^-1黏度标准物质。研究毛细管法多温度点定值技术，分析试验温度对黏度计常数的影响，通过对玻璃的热膨胀修正得到定值温度为20℃～100℃的多温度点黏度标准物质，定值结果的不确定度为0.40%～0.62%(k=2)。该标准物质可用于黏度测定仪的检定以及黏度测定方法的验证。     

硫系玻璃熔体的黏度测试方法和黏温方程

黏度作为硫系玻璃重要的物理性质,是控制玻璃制备过程和评估玻璃应用情况的重要参数。黏度测试方法和黏温关系数学方程一直是硫系玻璃研究领域的热点。本文介绍了硫系玻璃熔体多种黏度测试方法的适用范围和开发历程;综述了硫系玻璃熔体黏温关系数学方程的演化过程,对不同黏温关系方程的准确性进行了分析和讨论;最后针对硫系玻璃熔体黏温关系方程的探索,进行了讨论和展望。     

氟硅油用作高温航空润滑油的研究

对氟硅油的性能进行了研究,主要包括热氧化安定性、润滑性和黏温性能等.结果表明:氟硅油的热氧化稳定性温度可达250℃；通过分子结构中引入了Cl元素,其润滑性能得到明显的提高；此外还具有优异的黏温性能和低温性能.该油的最高使用温度比酯类油提高了50℃以上.     

非室温下一种黏度传递液定值方法的探讨

甲基硅油具有稳定、均匀、准确的黏度量值特性,是美、日、德等国使用的黏度标准物质的主要成分。文中采用标准毛细管黏度计装置在20～100℃温度区间内对其进行定值尝试,并用振动管法进行密度测量。动力黏度结果的相对扩展不确定度为0. 6%(k=2),经比较验证具有一定的可靠性。     

基于聚醚的热增黏接枝聚合物的合成及性能

聚合物水溶液黏度通常会随温度升高而降低。为了解决高温下聚合物溶液的增黏难题,文中利用聚醚(F127)分别与丙烯酸、丙烯酰胺、2-丙烯酰胺基-2-甲基丙磺酸接枝共聚,得到了系列热增黏聚合物。考察了聚合条件、聚合物浓度、亲水单体的性质对聚合物溶液热增黏能力的影响。结果表明,聚合物浓度越高、聚合物相对分子质量越高,聚合物的热增黏性能越好,热缔合温度也越低。     

Propagation of Uncertainty in Establishing the Viscosity Scale

The viscosity scale is established by step up method, in which several master viscometers and standard liquids are used. Starting point is the distilled water. The basic measurand is the efflux time. Uncertainty in the determination of viscometer constant of a viscometer or the kinematic viscosity of standard liquid at a particular step is carried forward for subsequent steps. The expressions for uncertainty for viscometer constant of the viscometer and kinematic viscosity of the liquid in nth step have been derived. Various applicable corrections and their contribution to uncertainty have been discussed.     

热塑增韧环氧树脂体系的黏温特性

采用增韧用热塑性塑料粉料与常用环氧树脂的共溶和共混物的黏温特性进行研究。研究表明,溶解于环氧树脂中的热塑性塑料粉料是环氧树脂体系基础黏度的主要贡献源,不同的热塑性塑料粉料在环氧树脂中的溶解特性具有显著不同的特点,环氧树脂/热塑性塑料粉料共混物也可以获得最低黏度,但不如共溶物显著,共混物黏度的提高主要表现为升温过程中热塑性塑料粉料在环氧树脂中的物理溶解。采用共混方法和共溶方法都可对环氧树脂/热塑体系的黏温特性进行有效调控。     

Comparison of Several Diffusion Equations in the Calculation of Viscosity and its Relation to Dissolution Rate

The viscosity of polymeric solutions as measured by a rotational viscometer may not be the viscosity of the environment through which a solute molecule diffuses. By use of the Stokes-Einstein equation a viscosity, which is not affected by the mechanics of the viscometer, may be calculated if the size and diffusivity of the solute molecule are determined. The values of such viscosity calculated by using several diffusion equations compare favorably with the value calculated with the Stokes-Einstein equation. The dissolution rates of benzoic acid in aqueous solutions of three non-ionic suspending agents is related to the viscosity.     

铁磁材料阿留麦尔居里温度测试研究

铁磁材料阿留麦尔合金具有稳定的居里温度,常作为热分析温度校准的标准物质。介绍了阿留麦尔合金原料的选择、成分测试以及成分差异对居里温度的影响、居里温度的测量方法。采用可溯源的温度有证标准物质对仪器进行温度校正后,选取铟熔点标准物质作为外标物质,实现溯源至SI单位。测试了铁磁材料阿留麦尔居里点国家有证标准物质GBW(E)130668(居里温度为161.6℃,U=2.1℃,k=2),测试值为161.8℃,测试结果在认定值的不确定度范围内。     

An accurate estimation method of kinematic viscosity for standard viscosity liquids

Deming's method of least squares is introduced to make an accurate kinematic viscosity estimation for a series of 13 standard-viscosity liquids at any desired temperature. The empirical ASTM kinematic viscosity-temperature equation is represented in the form loglog(v+c)=a–b log T, where v (in mm². s^–1) is the kinematic viscosity at temperature T (in K), a and b are the constants for a given liquid, and c has a variable value. In the present application, however, c is assumed to have a constant value for each standard-viscosity liquid, as do a and b in the ASTM equation. This assumption has since been verified experimentally for all standard-viscosity liquids. The kinematic viscosities for the 13 standard-viscosity liquids have been measured with a high accuracy in the temperature range of 20–40°C using a series of the NRLM capillary master viscometers with an automatic flow time detection system. The deviations between measured and estimated kinematic viscosities were less than ±0.04% for the 10 standard-viscosity liquids JS2.5 to JS2000 and ±0.11% for the 3 standard-viscosity liquids JS15H to JS200H, respectively. From the above investigation, it was revealed that the uncertainty in the present estimation method is less than one-third that in the usual ASTM method.     

Liquid viscosities and densities of HFC-134a+glycol mixtures

Liquid viscosity and density of six binary mixtures of HFC-134a with glycols [ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (400), and polypropylene glycol (2000)] have been measured in the temperature range from 273 to 333 K. The viscosity was measured by a rolling-ball viscometer calibrated with standard liquids of viscosities and densities (JS5, JS10, JS20, and JS50). The density was measured with a glass pycnometer. The uncertainties of the measurements were estimated to be less than 3.4 % for viscosity and 0.04 % for density, respectively. An equation is given to represent the obtained viscosity values as a function of weight fraction and temperature.     

The viscosity of five liquid hydrocarbons at pressures up to 250 MPa

This paper reports new measurements of the viscosity of toluene, n-pentane, n-hexane, n-octane, and n-decane at pressures up to 250 MPa in the temperature range 303 to 348 K. The measurements were performed with a vibrating-wire viscometer and with a relative method of evaluation. Calibration of the instrument was carried out with respect to reference values of the viscosity of the same liquids at their saturation vapour pressure. The viscosity measurements have a precision of ±0.1% but the accuracy is limited by that of the calibration data to be ±0.5%. The experimental data have been represented by polynomial functions of pressure for the purposes of interpolation. The data are also used as the most precise test yet applied to a representation of the viscosity of liquids based upon hard-sphere theory.     

Viscosity measurement of Newtonian liquids using the complex reflection coefficient

This work presents the implementation of the ultrasonic shear reflectance method for viscosity measurement of Newtonian liquids using wave mode conversion from longitudinal to shear waves and vice versa. The method is based on the measurement of the complex reflection coefficient (magnitude and phase) at a solid-liquid interface. The implemented measurement cell is composed of an ultrasonic transducer, a water buffer, an aluminum prism, a PMMA buffer rod, and a sample chamber. Viscosity measurements were made in the range from 1 to 3.5 MHz for olive oil and for automotive oils (SAE 40, 90, and 250) at 15 and 22.5degC, respectively. Moreover, olive oil and corn oil measurements were conducted in the range from 15 to 30degC at 3.5 and 2.25 MHz, respectively. The ultrasonic measurements, in the case of the less viscous liquids, agree with the results provided by a rotational viscometer, showing Newtonian behavior. In the case of the more viscous liquids, a significant difference was obtained, showing a clear non-Newtonian behavior that cannot be described by the Kelvin-Voigt model.     

Effect of hydrogen bonding on the viscosity of alcohols at high pressures

Viscosities of several alcohols and vinyl acetate were measured with a rollingball viscometer. The viscosity measurements were performed at temperatures from 298 to 413 K and pressures up to 195 MPa with an accuracy of ±2%. The viscosities of the alcohols show a stronger dependence on temperature compared with that of substances that do not form hydrogen bonds. In addition, the secondary and tertiary alcohols show a viscosity-temperature dependence not in accordance with an Arrhenius law. An effect of pressure on the association of alcohol molecules resulting from hydrogen bonding was not resolved by means of viscosity data. Separation of the effect of association size upon increasing temperature from the viscosity caused by the change of specific volume was carried out using the Utracki free volume model.     

比较振荡管法和比重瓶法测定15~80℃原油视密度换算标准密度的研究

原油标准密度(20℃)是原油理化指标中重要的一项。通过使用安东帕(Anton Paar)DMATM 35 V4 Ex Petrol防爆便携密度计等设备,对多个油田的油井采出液原油试样在15～80℃时分别用比重瓶法、震荡管密度计法进行密度检测,绘制密度-温度曲线,推导和完善了经验公式,并给出了一个以测试密度和温度为参数的计算公式。将振荡管密度测试法与石油计量表联合求解原油标准密度,相对误差控制在±0.5%以内,使在现场快速得到原油标准密度参数成为可能。