Calibration of rolling ball viscometer in the intermediate reynolds number region

The applicability of proposed correlations for the calibration of a rolling ball viscometer in the intermediate Reynolds number region (0.3 < Re 1000) has been studied. The constants for the equation correlating ball roll time with viscosity have been derived and compared with their experimental values. The dependency of these constants on temperature and on the dimensions of the viscometer has also been described which may help in the optimal design of a rolling ball viscometer.     

Statistical mechanics and artificial intelligence to model the thermodynamic properties of pure and mixture of ionic liquids

In this paper, the volumetric properties of pure and mixture of ionic liquids are predicted using the developed statistical mechanical equation of state in different temperatures, pressures and mole fractions. The temperature dependent parameters of the equation of state have been calculated using corresponding state correlation based on only the density at 298.15 K as scaling constants. The obtained mean of deviations of modified equation of state for density of al pure ionic liquids for 1662 data points was 0.25%. In addition, the performance of the arti-ficial neural network (ANN) with principle component analysis (PCA) based on back propagation training with 28 neurons in hidden layer for predicting of behavior of binary mixtures of ionic liquids was investigated. The AADs of a col ection of 568 data points for al binary systems using the EOS and the ANN at various temperatures and mole fractions are 1.03%and 0.68%, respectively. Moreover, the excess molar volume of all binary mixtures is predicted using obtained densities of EOS and ANN, and the results show that these properties have good agree-ment with literature.     

VISCOSITY OF GLYCEROL AND ITS AQUEOUS SOLUTIONS MEASURED BY A TANK-TUBE VISCOMETER

In this paper we demonstrate several series of experiments for the measurement of viscosity of neat glycerol and its aqueous solutions using a tank-tube viscometer. Measuring viscosity of highly viscous liquids with the tank-tube viscometer is easier than other types of viscometers. This inexpensive viscometer continuously generates numerous reproducible viscosity data of highly viscous neat glycerol and its aqueous solutions under given experimental conditions such as a desired temperature and a desired concentration of water in aqueous glycerol solutions.

Fabricating the tank-tube viscometer is inexpensive, since this viscometer does not need sophisticated accessories such as a high-pressure liquid pump, a sensitive pressure sensor, and an accurate flow meter. The tank-tube viscometer consists of a large-diameter reservoir and a long, small-diameter, vertical tube.

The viscosity equation was developed under the following assumptions. Both the quasi steady state approach and the negligible friction loss due to a sudden contraction between the reservoir tank and the tube are valid. The kinetic energy of the emerging stream from the bottom end of the vertical tube of the tank-tube viscometer also is assumed to be negligible. Very viscous glycerol and its aqueous solutions were used to test the viscometer by comparing viscosity values from the viscometer with those from literatures.

The main objective of this study is to demonstrate effects of water as well as temperature on viscosity of aqueous glycerol solutions, applying experimental data of accumulated amounts of aqueous glycerol solutions at various drain durations to the newly-developed viscosity equation for the fabricated tank-tube viscometer.     

A rotating sphere viscometer

The use of a rotating sphere viscometer for the measurement of parameters in the flow curves of inelastic as well as viscoelastic liquids is examined. An experimental investigation of the primary flow around a sphere rotating in Newtonian and viscoelastic liquids is carried out by using a new “three-dimensional particle technique.” Currently available theoretical analyses of rotation of a sphere in viscoelastic liquids are shown to be inadequate to describe the experimental primary velocity distribution data. Theoretical results for the primary distribution derived on the basis of a creeping flow of a power law liquid are found to describe the experimental data well. This distribution is then used to derive torque–angular velocity relationships, which are then confirmed experimentally for both inelastic and viscoelastic liquids. The results of this work justify the use of a rotating sphere viscometer as a useful tool for the measurement of parameters of flow curves of inelastic and viscoelastic liquids.     

聚合物的内压与新溶解度参数

由文献发表的pVT数据回归得到了许多液态聚合物的Tait方程参数。据此能够获得各种密度下聚合物的等容线。将这些等容线斜率的对数与密度作图,则无例外地发现这些作出的线是很好的直线,故可建立一个聚合物的通用内压方程。它有两个特性常数,分别决定于直线的斜率和截距。它能用来准确地计算298．15K时各种液态聚合物的内压;据此,得到了90个聚合物的新溶解度参数值。     

THE TWO-THIRDS POWER MODEL FOR PREDICTING DIFFUSION COEFFICIENTS IN LIQUIDS

Most of the models found in the literature for predicting diffusion coefficients in liquids take the viscosity of the solution as inversely proportional to the diffusivity. A model (previously derived for sucrose-water system)which considers the viscosity raised to the two-third power, is evaluated here using published data for the Benzene—Cylohexane, Ethanol-Water and Acetone-Chloroform systems. These results, and results for the sucrose-water system are compared with the experimental values, and with those obtained using the Hartley—Crank equation. Better agreement with the experimental values at low and in the middle of the concentration range was found when diffusivities were calculated using the model proposed than when using the Hartley-Crank equation.     

RHEOLOGICAL CHARACTERIZATION OF NON-NEWTONIAN FLUIDS WITH A NOVEL VISCOMETER

A hydrostatic head viscometer and its novel viscosity equation were developed to determine flow characteristics of Newtonian and non-Newtonian fluids. The objective of this research is to test capabilities of the hydrostatic head viscometer and its novel non-Newtonian viscosity equation by characterizing rheological behaviors of well-known polyethylene oxide aqueous solutions as non-Newtonian fluids with 60 wt.% sucrose aqueous solution as a reference/calibration fluid. Non-Newtonian characteristics of 0.3-0.7 wt.% polyethylene oxide aqueous solutions were extensively investigated with the hydrostatic head viscometer and its non-Newtonian viscosity equation over a 294-306 K temperature range, a 0.14-40 Reynolds number range, and a 55-784 s^-1 shear rate range at atmospheric pressure. Dynamic viscosity values of 60 wt.% sucrose aqueous solution were determined with the calibrated hydrostatic head viscometer and its Newtonian viscosity equation over a 3-5 Reynolds number range at 299.15 K and atmospheric pressure and compared with the literature dynamic viscosity value.     

RHEOLOGICAL CHARACTERIZATION OF NON-NEWTONIAN FLUIDS WITH A NOVEL VISCOMETER

A hydrostatic head viscometer and its novel viscosity equation were developed to determine flow characteristics of Newtonian and non-Newtonian fluids. The objective of this research is to test capabilities of the hydrostatic head viscometer and its novel non-Newtonian viscosity equation by characterizing rheological behaviors of well-known polyethylene oxide aqueous solutions as non-Newtonian fluids with 60 wt.% sucrose aqueous solution as a reference/calibration fluid. Non-Newtonian characteristics of 0.3–0.7 wt.% polyethylene oxide aqueous solutions were extensively investigated with the hydrostatic head viscometer and its non-Newtonian viscosity equation over a 294–306 K temperature range, a 0.14–40 Reynolds number range, and a 55–784 s^?1 shear rate range at atmospheric pressure. Dynamic viscosity values of 60 wt.% sucrose aqueous solution were determined with the calibrated hydrostatic head viscometer and its Newtonian viscosity equation over a 3–5 Reynolds number range at 299.15 K and atmospheric pressure and compared with the literature dynamic viscosity value.     

Viscosity of coal-derived liquids in the brown coal liquefaction (BCL) process

The viscosity of the liquids derived from Victorian brown coal in the two-stage Brown Coal Liquefaction (BCL) process was measured by using a rotational viscometer. The effects of temperature and liquid properties on the viscosity were determined for a wide variety of the samples which were prepared at different liquefaction and/or distillation conditions. The equations for estimating their viscosities were obtained by using these results.These equations are similar to Andrade's and involve two parameters of temperature and the liquid properties. The latter is represented by the 50 vol.%-off boiling point for the distillate fractions and the ratio of benzene insolubles-pyridine solubles content to benzene solubles content for the heavy fractions (vacuum residue).     

The temperature dependence of the doolittle equation parameter for polymer liquids

The Doolittle equation parameter for polymer liquids is a function of temperature. Its dependence on temperature can be expressed by a quadratic equation. The constants in the equation are determined for four vinyl-type polymer liquids: polystyrene (PS), poly(vinyl acetate) (PVAc), polydimethylsiloxane (PDMS), and polyisobutylene (PIB). It was found that the Doolittle parameter decreases with increasing temperature. Equations are presented for the pressure and temperature coefficients of viscosity, isoviscous temperature coefficient of volume, and the constant K_m in the Miller equation. Comparisons of the predictions of the equations, with those in the literature, are favorable. © 1993 John Wiley & Sons, Inc.     

Application of grinding kinetics analysis of inorganic powders by a stirred ball mill

The need for ultra fine particles has been increasing in the preparation field of raw powders such as fine ceramics and high functional products. A series of wet grinding experiments were carried out on inorganic powders such as calcite, pyrophyllite and talc by a stirred ball mill. The grinding rate constant K’ in the equation of grinding kinetics was examined based on the grinding kinetics analysis as the same type of function of a previous paper on a vertical type planetary ball mill. The experimental particle size distribution of the ground products was obtained in various grinding conditions. The grinding rate constants K and K’ were expressed by empirical equation involving experimental conditions by a stirred ball mill. The empirical equation on the grinding rate constant was expressed in terms of a function involving the ball diameter of grinding balls, the median diameter of feed material, and Bond’s work index of material, in the experimental conditions. The values of empirical constants C1 and C₂ were 21.13 and 0.0109 on K, while C₁ and C₂ were 120.99 and 0.0192 on K′, respectively. And the particle size distribution of ground products of each test material for a given grinding time was found to be expressing the selection function (the specific rate of breakage) which was obtained from the grinding kinetics analysis. In this study, the grinding rate change on calcite and pyrophyllite was similar at the same experimental operation condition. However, in the case of talc, it was observed that the grinding rate was not increased compared with other samples.     

Determination and Correlation of Solubilities of Four Novel Benzothiazolium Ionic Liquids with PF6^- in Six Alcohols

Four novel benzothiazolium ionic liquids with 6PF- （[C1Bth][PF6], [C4Bth][PF6], [C5Bth][PF6] and [C6Bth][PF6]） were synthesized, and the rang of their melting points were determined between 358.35 K-424.05 K. The relationship of their melting points and the length of the straight alkyl chain on cation reflected‘S’ type ten-dency. Then, the solubilities of the four ionic liquids in six lower alcohols （methanol, ethanol, 1-propanol, 2-propanol, 1-butanol and 2-methyl-1-propanol） were measured in the temperature rang of 253.15-383.15 K at at-mospheric pressure with static analytical method, respectively. It was found that [C6Bth][PF6] in all investigated ionic liquids had the largest solubility in six alcohols and the solubility of [C4Bth][PF6] in methanol was very sensi-tive for temperature in 313.15-333.15 K, which was so-called “temperature-sensitivity”. This feature is of great significance to their application of catalyzing reaction or extraction process, and makes the recovery and reuse of ionic liquids （ILs） become easier. Moreover, the experimental solubility data were correlated with the modified Apelblat equation andλh equation, respectively. It was found that the result of correlation using two divided tem-perature ranges was better than that of using the whole temperature range.     

[bmim][BF_4]、[bmim][PF_6]离子液体及其与DMF二元体系在293.15～338.15K下的粘度

为获得离子液体与有机物物理性质的数据,常压下,293.15～338.15 K温度范围内,分别测定了1-丁基-3-甲基咪唑四氟硼酸盐（[bmim][BF4]）、1-丁基-3-甲基咪唑六氟磷酸盐（[bmim][PF6]）2种咪唑类离子液体以及它们和N,N-二甲基甲酰胺（DMF）构成的2个二元体系的粘度,采用Vogel-Tamman-Fulcher（VFT）方程和Arrhenius-like方程对所测粘度数据进行关联。结果表明,同一温度下,3种纯溶液粘度大小顺序依次为：DMF〈[bmim][BF4]〈[bmim][PF6]。[bmim][BF4]、[bmim][PF6]离子液体及其与DMF构成的二元体系的粘度均随着温度的升高和DMF摩尔分率的增加而降低。实验条件下,DMF＋[bmim][BF4]和DMF＋[bmim][PF6]二元体系的粘度变化范围分别为1.26～125.5 MPa·s和1.11～165.7 MPa·s。VFT方程对于DMF-[bmim][BF4]与DMF-[bmim][PF6]体系的关联结果比Arrhenius-like方程较好,其总平均绝对误差、总平均相对误差、以及总平均标准方差分别为0.561 9 MPa·s和0.918 6 MPa·s、0.026 8 MPa·s和0.020 9 MPa·s、0.725 5 MPa·s和1.125 1 MPa·s。     

Reaction kinetics of pulverized coal-chars derived from inertinite-rich coal discards: Gasification with carbon dioxide and steam

An investigation was undertaken to determine the kinetics of gasification of coal-chars (pulverized) derived from typical South African inertinite-rich (high-ash) coals involving char reactions with carbon dioxide and steam and the effects of carbon monoxide and hydrogen. The chars used were characterized with respect to structural, chemical, mineralogical and petrographic (maceral content) properties and gasification experiments were conducted in a TGA at atmospheric pressure with different gas mixtures within a temperature range of 1073–1223 K. The shrinking core model with a controlling surface reaction was shown to be applicable for the gasification of pulverized coal-chars consisting of essentially of carbon-rich particles. The validity of this model can be attributed to the core having an exceptional low porosity (high inertinite parent coal) and consequently negligible penetration of the gases. It was found that the gasification intrinsic reaction rates could be adequately described by Langmuir–Hinshelwood type rate equations and that established equations have been validated with corresponding constants according to new data processing procedures. It was found that the reaction rate constants for coal-chars derived from inertinite-rich (76–80%) coal discards were different to results published in the literature and that the intrinsic reaction rates differed only slightly (order of magnitude) for coal-chars with similar maceral (inertinite) compositions and different total ash contents. The marked inhibiting effect of the carbon monoxide and hydrogen on the carbon dioxide/carbon monoxide and steam/hydrogen gasification reactions is shown and relevant constants are reported. Experiments were done and models evaluated for a multi-component gasification mixture consisting of a feed mixture of carbon dioxide, carbon monoxide, steam and hydrogen. Reaction constants determined with results from binary mixtures were used to predict results and it was found that the overall rate is best described with the assumption that the important reactions proceed on separate sites.     

Densities and Viscosities of 1-butyl-3-methylimidazolium Hexafluorophosphate [bmim][PF6] ＋ CO2 Binary System： Determination and Correlation

A gas-dissolving device was designed and connected to the falling-body viscometer, which was used to determine the viscosities of liquids in our lab before. The equipment can be used to determine the gas composition, the densities and viscosities of the solution at the same time. The densities and viscosities of [bmim][PF6] ＋ CO2 binary system were determined in the temperature range of 313.2 to 413.2 K and pressure range of 5.0 to 25.0 MPa by the equipment. Then the viscosities of [bmim][PF6] ＋ CO2 binary system at constant temperature, constant pressure, and different temperature and pressure were correlated, respectively. For the correlation at different tempera- ture and different t3ressure for different concentration mixtures the average relative deviation ARD is 0.037.     

DSC法测定醋酸-水溶液的比热

利用差示扫描热量计(DSC)测定了醋酸水溶液在温度范围为293.15~359.15K和整个组成范围下的比热,并把比热的测量值与文献值进行了比较, 实验的测量误差小于±2%, 测得的醋酸-水的比热数据完全能满足工程设计的需要。同时把醋酸-水的比热与组成与温度进行了关联,并利用最小二乘法回归出所提方程中的参数,最后导出了一个计算Cp的多项式方程,此方程中既包含温度又包含组成,因此利用此方程可以计算醋酸-水体系在测定温度和组成下的Cp。把用该方程的计算值与实验值进行了比较,117个数据点的总绝对平均相对误差为0.54%。所提方程可应用于对苯二甲酸生产中换热器的设计及相关体系热量平衡的计算,具有实用意义。     

含催化剂的乙二醇和二甘醇黏度测定及关联

在常压、313~413 K下,采用ND J-1旋转式黏度计,测定了含NY2催化剂的乙二醇和二甘醇的黏度.采用黏度Andrade关系式,将黏度数据与NY2催化剂质量分数和温度进行关联,得到经验关系式.结果表明,由经验方程计算值与实验结果基本相符,为催化水合制乙二醇的反应器设计和优化分离设备提供必要的基础数据.     

计算正常沸点下液体汽化热的方法

在分析了文献上计算汽化热的主要公式的基础上,解Clapeyron方程;并将上限延伸到临界点的温度和压力,再引进参数K_1,K_2值,提出了计算液体汽化热的新公式,即 r_b=K_2{[T_bT_c/（T_c-T_b）]+K_1}logP_c式中 参数K_2则考虑不同分子结构提出不同的数值,以有助于计算的准确性。 本文用此新公式验算了31类共157种纯物质的液体汽化热,与实测值相比,平均误差为1.65％。     

二甲氧基甲烷饱和液体运动黏度

The kinematic viscosity values of the saturated liquid dtmethoxy memane are reported over the temperature range from 248. 467 to 353. 154 K along the saturation line made with a calibrated Ubbelohdetype capillary viscometer. The total experimental uncertainty is less than 0. 71%. In addition, the results were correlated as a function of temperature for the kinematic viscosity equation of saturated liquid. The absolute average deviation and the maximum deviation of the experimental results from the correlated equation are 0. 35% and 1.45%, respectively.     

有机物质粘度的加压测定和高压液体粘度与密度的关联方程

对落体式粘度计进行了结构改进.在298.15～348.15K(±0.05K)、由常压至29.5MPa的范围内,测定了四氢呋喃、丙酮、乙腈和苯胺4种纯物质,以及苯+环己烷、正丙醇+正庚烷和正丁醇+正庚烷3种二元混合物的液体粘度共294点.提出了高压液体粘度与密度的关联方程,lnφ=ln(l/μ)=A-lnρ+ξ(3ξ-4)/(1-ξ)~2-Cρ/(RT).用本式对最大压力范围为0.1～500MPa、最大温变幅度为170K的广泛类型物质的液体粘度数据共1049点进行关联和计算,计算值的总平均相对偏差为2.64%,远低于选作比较的Dymond等的关联方程.