基于Eyring绝对速率理论的流体混合物黏度推算

为了建立起一个统一的、可同时应用于纯质与混合物高压黏度计算的绝对速率理论模型,基于此前已有的纯质黏度模型,提出了相应的混合法则,将其扩展至对混合流体的计算当中。为验证模型精度,首先选取了27种纯质流体,通过拟合其黏度数据得到模型参数。随后,对27种二元混合物以及3种三元混合物的黏度进行了计算。其中,对于二元混合物,仍需要引入额外的二元交互参数,可通过拟合混合体系黏度数据得到。结果表明,该黏度模型对所选纯质、二元混合物和三元混合物的黏度均有着较高的计算精度,其相对偏差的平均绝对值分别为1.54%、2.35%和3.86%,最大偏差为8.62%、12.9%和19.7%。最后,将本文模型与自由体积模型进行了比较,其对高黏度和互缔合流体的计算精度均高于后者。     

随机温度信号互相关法测量吸热型碳氢燃料密度

为实现超临界压力下吸热型碳氢燃料密度的准确测量,以相关测量技术为基础,设计搭建了一套密度在线测量系统。该系统在间距148 mm的管道上下游安装两只具有相同热电特性的K型热电偶作为互相关法的传感器,通过对热电偶检测到的随机温度信号进行相关计算,得出该信号经过上下游热电偶的延迟时间,计算得到流体截面的平均流速,在已知质量流量后,根据质量守恒定律进而求得流体密度。采用纯物质十二烷及质量比1∶1正辛烷/正庚烷二元混合物标定测量系统精度,实验结果与文献值的最大误差在±1.2%以内,平均相对误差小于0.6%。在此基础上,对压力p = 3.0、4.0、5.0 MPa,温度T = 302.0～529.6 K,吸热型碳氢燃料密度进行测量,该方法的应用为超临界压力下吸热型碳氢燃料密度的准确测量提供了新思路。     

基于UNIFAC-VISCO模型对胺类液体燃料黏度的推算

根据正丁胺、正己胺、正癸胺、正十二胺等与叔丁胺、正己烷、环己烷、苯、乙酸甲酯、乙酸乙酯、乙酸丁酯、丙酮以及醇类物质所组成的二元溶液黏度试验数据,结合Eyring溶液黏度理论与UNIFAC基团贡献法,建立了一种用以计算含胺类物质混合溶液黏度的理论模型,并且利用文献黏度试验数据在该模型的框架上回归得到新的基团对的UNIFAC模型参数,并利用所建模型与回归得到的参数对混合溶液黏度进行计算,计算的绝对平均偏差为3.1%,可以满足实际工程应用的要求。     

基于PLS快速剪枝法的RBF神经网络软测量模型建模方法和应用

提出一种从RBF神经网络隐含层的输出信息出发，通过PLS快速剪枝法，一次性剪去多余节点，生成最优规模的数学解析模型的方法。并用该方法建立了某化工企业精对苯二甲酸(PTA)晶体平均粒径的软测量模型，针对实际对象进行仿真研究，结果表明，该方法计算速度快，建立的模型精度高，适合实际工程应用的需求。     

立方型状态方程结合Eyring理论在液体混合物黏度计算中的应用

Cubic equations of state (EOS) have been combined with the absolute rate theory of Eyring to calculate viscosities of liquid mixtures. A modified Huron Vidal gE-mixing rule is employed in the calculation and in comparison with the van Laar and the Redlich-Kister-type mixing rule. The EOS method gives an accurate correlation of liquid viscosities with an overall average deviation less than 1% for 67 binary systems including aqueous solutions. It is also successful in extrapolating viscosity data over a certain temperature range using parameters obtained from the isotherm at a given temperature and in predicting viscosities of ternary solutions from binary parameters for either polar or associated systems.     

Calculation of Viscosities of Liquid Mixtures Using Eyring’s Theory in Combination with Cubic Equations of State

1 INTRODUCTON The viscosity, particularly that of liquid mixtures is very important in engineering calculations involved in the process design for petroleum and other chemica industries. Since the successful development of a one-parameter equation for correlating the liquid vis cosity of nonpolar mixtures by Grunberg and Nissan[1] many other models have been proposed. Most of them are based on the corresponding state principle, the absolute rate theory of Eyring[2], or the free volume the…     

A new one parameter viscosity model for binary mixtures

The Grunberg & Nissian equation with one parameter is widely recommended in the viscosity calculation. However, it is demonstrated that this equation fails to generate satisfactory results for size‐asymmetric mixtures containing large and small molecules. In this work, a new one parameter viscosity model for binary mixtures has been developed on the basis of Eyring's absolute reaction rate theory and the Flory‐Huggins equation. The concept of molecular surface fraction is introduced for modeling liquid mixture viscosities. The viscosity calculations of the new equation are compared with the Grunberg & Nissian equation for a broad range of chemical mixtures including 527 binary systems (containing 63 binary ionic liquid cosolvent systems) and total 17,268 viscosity points. The new equation was found to have an improved performance over the frequently employed Grunberg & Nissian equation, especially for size‐asymmetric mixtures containing large and small molecules. © 2010 American Institute of Chemical Engineers AIChE J, 57: 517–524, 2011     

Viscosity model of deep eutectic solvents from group contribution method

Deep eutectic solvents (DESs), a novel category of sustainable solvents, are expected to achieve the design of the chemical processes without utilizing or generating harmful chemicals. In this work, based on the mathematical model inspired by the transition state theory, the group contribution method is used to accurately predict the viscosity of DESs. The model is constrained by Eyring rate theory and hard sphere free volume theory. A dataset of 2229 experimental viscosity data points of 183 DESs from literature is used to determine the model parameters and subsequently verify the model. The rules introduced by this model are simple and easy to follow. The results show that the proposed model is capable to predict the viscosity of DESs with very high accuracy, using only temperature and composition as inputs. The average absolute relative deviations (AARDs) of the model are 8.12% and 8.64% over the training and test sets, respectively, and the maximum ARD is 34.63%. Therefore, the as-proposed model can be considered a highly reliable tool for predicting the viscosity of DESs when experimental data are absent. It will provide useful guidance for the synthesis of DESs with specific viscosity to meet different application requirements and promote their industrial-scale implementation.     

借助变阱宽方阱链流体状态方程模拟非电解质体系表面张力和粘度(英文)

The equation of state(EOS)for square-well chain fluid with variable range(SWCF-VR) developed in our previous work based on statistical mechanical theory for chemical association is employed for the correlations of surface tension and viscosity of common fluids and ionic liquids(ILs).A model of surface tension for multi-component mixtures is presented by combining the SWCF-VR EOS and the scaled particle theory and used to produce the surface tension of binary and ternary mixtures.The predicted surface tensions are in excellent agreement with the experimental data with an overall average absolute relative deviation(AAD)of 0.36%.A method for the calculation of dynamic viscosity of common fluids and ILs at high pressure is presented by combining Eyring’s rate theory of viscosity and the SWCF-VR EOS.The calculated viscosities are in good agreement with the experimental data with the overall AAD of 1.44% for 14 fluids in 84 cases.The salient feature is that the molecular parameters used in these models are self-consistent and can be applied to calculate different thermodynamic properties such as pVT,vapor-liquid equilibrium,caloric properties,surface tension,and viscosity.     

基团贡献状态方程的开发与热力学模型参数的理论预测

热力学模型是研究流体相行为和热力学性质的重要工具。理论模型的有效应用离不开模型参数的确定。为赋予热力学模型的预测功能,目前的策略一是建立基团贡献(GC)状态方程(EOS),二是探索热力学模型参数的理论预测方法。围绕先前开发的变阱宽方阱链流体状态方程(SWCF-VR),采用基团贡献法思路获得了不同基团对模型参数的贡献值,建立了GC-SWCF方程,证实GC-SWCF方程能满意预测纯物质的密度。进一步将似导体屏蔽模型(COSMO)与SWCF结合,基于COSMO方法获得了192种有机化合物的SWCF方程的模型参数,这是一种不依赖实验数据确定模型参数的理论方法。发现COSMO+SWCF能较好地预测纯物质的密度。引入一个与温度无关的二元交互作用可调参数后,GC-SWCF与COSMO+SWCF都可应用于二元混合物密度与气液相平衡的计算中。     

竖直平板间液桥形状的观测与预测模型开发

了解析湿工况下液桥对管翅式换热器性能的影响,需要对液桥形状进行实验研究并建立描述液桥形状的方法。通过搭建可视化实验台观察了液桥在竖直平板间的形状,并测量了液桥的接触线和接触角。实验研究了不同体积、不同平板间距、不同平板材料间形成的液桥,并通过实验数据开发了能够描述液桥形状的关联式,包括接触线伸长比和接触角分别与Bond数的关联式。还根据关联式建立了描述液桥形状的方法并将结果与实验数据进行对比,对比结果显示接触线的描述方法平均误差为3.4%,接触角的描述方法平均误差为7.9%。     

基于IFOA-KELM-MEA模型的游梁式抽油机采油系统井下工况的短期预测

实现对井下工况的预测是及时掌握抽油井生产状态的有效方法,对提高油井生产效率和降低维护成本具有十分重要的意义。采用混沌理论实现抽油井井下工况的短期预测,首先将所提取的示功图的不变曲线矩特征向量作为预测变量,在证明其数据序列具有混沌特性后,由核极限学习机（kernel extreme learning machine,ELM）建立混沌时间序列预测模型,对其中的几个不确定参数采用改进的果蝇优化算法（improved fruit fly optimizationalgorithm,IFOA）进行优化选取,IFOA采用全局群体多样进化和局部个体随机变异的策略,最后,对模型所预测的结果进行物元分析（matter-element analysis,MEA）,诊断其属于哪种故障类型。由某油田作业区的两口生产井进行实例验证,结果表明所提出的IFOA-KELM-MEA预测模型是合理有效的。     

PSRK模型的修正混合规则及其应用于聚合物溶液汽液平衡的预测

To extend the PSRK(predictive Soave-Redlich-Kwong equation of state)model to vapor-liquid equilibria of polymer solutions,a new EOS-gE mixing rule is applied in which the term ∑ xi ln(b/bi)in the PSRK mixing rule for the parameter a,and the combinatorial part in the original universal functional activity coefficient(UNIFAC)model are cancelled.To take into account the free volume contribution to the excess Gibbs energy in polymer solution,a quadratic mixing rule for the cross co-volume bij with an exponent equals to 1/2 is applied [b1/2 ij= 1/2(b1/2 i b1/2 j)].The literature reported Soave-Redlich-Kwong equation of state(SRK EOS)parameters of pure polymer are employed.The PSRK model with the modified mixing rule is used to predict the vapor-liquid equilibrium(VLE)of 37 solvent-polymer systems over a large range of temperature and pressure with satisfactory results.