【作者】 段志青；

【导师】 马友光；

【作者基本信息】 天津大学 ， 化学工程， 2005， 硕士

【摘要】 非牛顿流体普遍存在于化工、食品及生物医学等领域,严格地说,牛顿流体只是非牛顿流体的一种特殊形式。非牛顿流体涉及许多工业过程的工艺、设备、效率和产品质量,也和人类本身的生活与健康密切相关,因此,对非牛顿流体性质及行为的研究具有重要意义。氨基酸、维生素、葡萄糖是生命体不可缺少的营养成分,广泛用于临床治疗及日常营养补充。生物体液、血液均为非牛顿流体,研究营养类分子在非牛顿流体中扩散,对控制扩散过程、指导临床治疗具有实际意义。聚丙烯酰胺与生物体液均为假塑性流体,并且对聚丙烯酰胺的基本性质已经有明确的认识,本文采用聚丙烯酰胺水溶液作为非牛顿流体,研究营养类分子在非牛顿流体中的扩散。粘度和密度是溶液的基本性质,本文采用比重瓶法测量了系统的密度,乌氏粘度计测量了系统的粘度,并且对密度和粘度进行了关联,计算出298.15K时这些分子在0.05%PAM水溶液中的表观摩尔体积,对实验结果和计算结果进行了分析和讨论。采用激光实时全息干涉法、CCD图像采集和图像数字处理技术,测得了298.15K氨基酸(甘氨酸、精氨酸、丝氨酸、苏氨酸、缬氨酸),维生素(B1、B6、C)和无水葡萄糖在0.05%(质量分率)PAM水溶液中的扩散系数,作为对比研究,实验测定了298.15K时这三种维生素和无水葡萄糖在生理盐水(0.9%的NaCl水溶液)中的扩散系数。在现有的预测牛顿流体中无限稀释液相扩散系数关联方程的基础上,结合非牛顿流体的流变方程及粘度定义,提出非牛顿流体中预测无限稀释扩散系数关联方程。以牛顿流体液相扩散系数与粘度的关联方程为基础,结合所研究的系统提出一个新方程,用此方程对氨基酸在0.05%PAM水溶液中的扩散系数进行拟合,总平均误差在0.6%以下,拟合结果较好。更多还原

【Abstract】 Non-Newtonian fluid is often encountered in many fields such as chemical engineering, foodstuff, biology and clinic etc. Strictly, Newtonian fluid is only a special kind of non-Newtonian fluid. Non-Newtonian fluid is closely related to the technology, equipment and efficiency of many industrial processes, as well as the quality of production, moreover, it also virtually involves the life and health of human being, therefore, it is of key significance to study the characteristic and behavior of non-Newtonian fluid, as a result, more and more attention have been paid to it. Amino acids, vitamin and glucose are necessarily nutritious components to every body and have been widely used in clinic treatment and daily life. As well known, the body fluid and blood are typical non-Newtonian fluid, so it is very important to investigate the diffusion of the nutritious molecules in non-Newtonian fluid for controlling the diffused process and helping the clinical treatment. Both polyacrylamide (PAM) and body liquid are pseudoplastic fluid, in this paper, PAM aqueous solution has been used to study the diffusion behavior of the nutritious molecules in non-Newtonian fluid. Viscosity and density are the basic property of the solution. Densities were measured by a pycnometer and viscosities were measured by an Ubbelohde viscometer, and the experimental data were fitted respectively. The apparent molar volumes of the molecules in 0.05% PAM aqueous solution at 298.15K were also calculated, and the results were analyzed and discussed. The diffusivities of amino acids(glynine, arginine, serine, threonine and valine)、vitamin(B1, B6 and C) and glucose in PAM aqueous solution and vitamin and glucose in sodium chloride (NaCl) aqueous solution at 298.15K were measured by a real-time holographic interferometer, CCD picture collection and treatment technique. As a contrast, the diffusivities of vitamin and glucose in biologic brine (0.09% NaCl aqueous solution) were measured at 298.15K. On the basis of the existing equation estimating liquid diffusion coefficients of Newtonian fluid at infinite dilution, and combining the rheological equation and the viscosity definition of non-Newtonian fluid, a new model was proposed to predict the liquid diffusion coefficients in non-Newtonian fluid at infinite dilution. According to the equation correlating liquid diffusion coefficients with viscosity, a new correlating equation was developed and applied to calculate the diffusion coefficients of amino acids in PAM aqueous solution at 298.15K, the total average deviation between computed value and experimented data is below 0.6%, which shows a good fitting result.更多还原