Arefinia Reza, Shojaei Akbar
Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran 11365-9465, Iran.
J Colloid Interface Sci. 2006 Jul 15;299(2):962-71. doi: 10.1016/j.jcis.2006.03.004. Epub 2006 Mar 9.
The rheological properties of fuel suspensions with various solid loadings up to close their maximum packing fraction and suspending media having different viscosities are investigated using the rotational viscometer at relatively low shear rates in which suspensions behave as Newtonian fluids. Aluminum (Al) and ammonium perchlorate (AP) particles are major solid components of any solid fuel system which should be distributed uniformly inside a polymeric binder based on hydroxyl terminated polybutadiene (HTPB). The experimental data generated in this investigation indicates that the relative viscosity of the suspensions is independent of viscosity of polymer binder, but in addition to solid content, geometrical aspects of the solid particles affect strongly the relative viscosity of suspensions. Maximum packing fraction of filler is found to be suitable quantitative measure of filler characteristics such as size, size distribution, shape and structure. Consequently, it is revealed that the relative viscosity of fuel suspension is a unique function of reduced volume fraction (Phi). Based on analogy of viscosity enhancement of reactive resin with cure conversion and suspension with filler content, an empirical model with two adjustable parameters originated from resin gelation model is suggested. According to this model and experimental results obtained in this investigation, a generalized model is proposed to describe the relative viscosity as a function of solid content in which the adjustable parameters are found to be general constants. The generalized model which is expressed as mu(r) = (1-Phi)(0.3 Phi-2) is found to be quite accurate to predict the experimental data. Furthermore, the applicability and accuracy of the generalized model are evaluated using the viscosity data of some suspension systems reported in the literature.
使用旋转粘度计在相对较低的剪切速率下研究了固体负载高达接近其最大填充分数且悬浮介质粘度不同的燃料悬浮液的流变特性，在该剪切速率下悬浮液表现为牛顿流体。铝（Al）和高氯酸铵（AP）颗粒是任何固体燃料系统的主要固体成分，它们应均匀分布在基于端羟基聚丁二烯（HTPB）的聚合物粘合剂内部。本研究中产生的实验数据表明，悬浮液的相对粘度与聚合物粘合剂的粘度无关，但除了固体含量外，固体颗粒的几何形状对悬浮液的相对粘度有强烈影响。发现填料的最大填充分数是填料特性（如尺寸、尺寸分布、形状和结构）的合适定量度量。因此，揭示了燃料悬浮液的相对粘度是约化体积分数（Phi）的独特函数。基于反应性树脂粘度随固化转化率增加以及悬浮液粘度随填料含量增加的类比，提出了一个源自树脂凝胶化模型的具有两个可调参数的经验模型。根据该模型以及本研究中获得的实验结果，提出了一个广义模型来描述相对粘度作为固体含量的函数，其中可调参数被发现是通用常数。发现表示为μ(r) = (1 - Phi)(0.3 Phi - 2)的广义模型能够非常准确地预测实验数据。此外，使用文献中报道的一些悬浮液系统的粘度数据评估了广义模型的适用性和准确性。
