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无限稀释液相扩散系数的新关联方程 总被引:1,自引:0,他引:1
根据由统计力学所得扩散阻力方程并结合粘度定义,推导出无限稀释液相扩散系数基本方程。对常见的分子进行适当的假设,得到了无限稀释液相扩散系数方程的通用形式和一般形式。本文主程的准确性较高,且具有较强的理论基础和较广泛的使用范围。 相似文献
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The molecular dynamics(MD) was employed to simulate the diffusion coefficient of sodium chloride at infinite dilution in supercritical water from 703.2K to 763.2K and from 30 MPa to 45 MPa ,Based on the simulated data and the Patel-Teja(PT) equation of state and the Liu-Ruckenstein equation,an equation for calculating the diffusion coefficient of NaCl at infinite dilution in supercritical water is proposed,Both the agreement between the simulated and correlated data,and that between the simulated and predicted data of diffusion coefficients for NaCl in supercritical water ranging from 703.2K to 803.2K and from 25 MPa to 50MPa show that this equation is applicable for calculation of diffusion coefficients. 相似文献
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液体纯物质的粘度及扩散系数与蒸发潜热间的关系 总被引:1,自引:0,他引:1
刘洪勤 《高校化学工程学报》1993,7(1):1-7
本文结合流体的普遍化范德华理论和粘度与扩散系数的自由体积模型,导出了纯物质的液体粘度及分子扩散系数与蒸发潜热间的关系式。对30种纯物质的粘度与蒸发潜热间的关联误差为1.45%;对20种物质的自扩散系数与蒸发潜热间的关联误差为2.9%。所选物系包括强极性、弱极性和非极性分子。本工作为建立传递性质与平衡性质间的关系,以及提出粘度及扩散系数与温度间的新关联式打下了初步基础。 相似文献
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1引言菲克定律中的扩散系数DAB代表单位浓度梯度下的扩散通量,表证某个组分A在介质B中扩散的快慢,是物质的一种传递属性,类似于传热中的导热系数。但比导热系数更为复杂:它至少要涉及两种物质,因而有多种多样的组合方式;同时随温度的变化较大,还与气体的总压有关。故文献中扩散系数的数据难以齐全。而应用半经验公式估算时,精确度又欠佳[1].本文介绍一种简易方法,用以测定两组分混合气体的扩散系数。对其测定原理进行严谨而完整的分析论证,并通过实例说明其应用。2测定原理如图1所示,在一细长直立的玻璃管底都盛入纯液体入不… 相似文献
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溶剂在交联硅橡胶中无限稀释扩散系数测定 总被引:2,自引:0,他引:2
气相色谱法测定溶剂与聚合物材料之间的相互关系是一个快速、准确、方便的方法,为此利用气相色谱法测定了小分子溶剂在不同交联剂含量的交联硅橡胶中的无限稀释扩散系数,并研究了交联剂用量对无限稀释扩散系数的影响,这为研究交联硅橡胶特性提供了新方法。 相似文献
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根据物质的实验临界常数或与物质最基本分子结构相关的Joback或Lydersen临界常数估算法得到物质的临界常数,结合Lennard-Joned流体的对比状态方程,按照对应态原理得到了38种有机物分子的新的Lennard-Jones位能参数.由这些位能参数结合简单的组合规则,首次对一些高附加值的复杂实用有机物在313.15 K、16 MPa的超临界CO_2中的无限稀释扩散系数采用分子动力学模拟的方法进行了研究.模拟结果表明,采用这种新思路可以有效地预测超临界体系的扩散性质,满足超临界萃取工艺开发和设计的需要. 相似文献
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A theoretical model to correlate and predict the liquid diffusion coefficients in binary sys-tems has been developed.Based on this mode1 the diffusion coefficient of 73 binary systems have beencorrelated,the overall average deviation of the correlation for diffusion coefficients is 0.009.Forbinary systems the diffusion coefficients have been predicted from vapor liquid phase equilibrium(VLE)and vice versa. 相似文献
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溶剂极性对超临界乙醇中无限稀释扩散系数的影响 总被引:3,自引:0,他引:3
INTRODUCTION
Ethanol has more accessible critical properties(Tc =241 ℃, Pc =6.38 Mpa) than water and stronger solubility power than carbon dioxide. Nearcritical and supercritical ethanol is a compressible fluid exhibiting great tunability with both temperature and pressure. 相似文献
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1 INTRODUCTIONAccurate data on molecular diffusion are required for the design of chemical and physi-cal processes where mass transfer plays an important role.Expressions for estimatingtracer diffusion coefficients(i.e.binary diffusion coefficients at infinite dilution)areavailable for a number of different systems .The Akgerman and Gainer equa-tion has been known to give good predictions for the diffusion coefficients of gases inliquids.This study provides an approximation approach for predicting diffusioncoefficients of binary liquid systems from their viscosities. 相似文献
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Activity coefficients at infinite dilution for 26 solutes (paraffins, cycloparaffins, olefins, aromalics, n. chloroparaffins, chloroform, tetrachloromethane, acetates, ketones, alcohols and nitriles) in five solvents containing two functional groups of the same nature were determined by gas-liquid chromatography. The solvents employed were hexanediol, nonanediol, hexanedithiol, dodecanediamine and dodecanedinitrile. The influence of the second functional group is suggested from both the absolute values of the activity coefficients as well as from the selectivity values of these solvents with respect to paraffin-aromatic separation. 相似文献
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高压乙醇中的无限稀释扩散系数:实验测定与模型评价 总被引:2,自引:2,他引:0
The infinite diffusion coefficients of benzene, toluene, naphthalene, pyridine and p-nitroaniline in ethanol were measured by Taylor dispersion technique under 318-473 K and 0-16 MPa. The measurement accuracy of the established apparatus was first checked. The measured diffusion coefficient of the five organic solutes in ethanol did not change with pressure at low temperature, but it was significantly reduced with pressure increase when the temperature is higher than 373 K. Of the correlations available for polar solvents, the modified Wilke-Chang equation, the Yang-Zhang equation as well as the He-Yu equation were used to calculate the infinite diffusion coefficient. At low temperature,the three equations all agreed well with experimental results for both polar and non-polar solutes.However, the prediction accuracy was decreased sharply when the temperature was higher than 373 K,where the association factor of the solvent was varied with temperature as well as pressure. 相似文献