一类微反应器临界流量的数值模拟

发布时间：2018-05-18 03:13

  本文选题：纳米材料 + 旋转液膜反应器　； 参考：《北京化工大学》2015年硕士论文

【摘要】：旋转液膜反应器是一类以沉淀法制备硫酸钡等纳米材料的微反应器,它由两同轴等高的圆台构成,两圆台间充满不可压缩的粘性反应液。在制备纳米材料的过程中,反应液的加入量(体积流量)是一个恰当的值,这个量称为临界流量。纳米材料的制备过程均在临界流量下进行,临界流量只能通过实验测得。本文建立了旋转液膜反应器内流体运动的数学模型,并结合N-S方程和适当的边界条件,对临界流量进行了数值求解,并研究了临界流量随不同因素的变化规律。本文首先对实验中参数下的临界流量进行了数值模拟,临界流量的数值结果与实验结果吻合良好,验证了求解临界流量方法的可靠性,然后我们研究了其他参数的改变对临界流量的影响。研究结果表明,在小雷诺数时,临界流量Q与反应液的运动粘性系数成反比,即Q∝1/y；与反应器转子的转速Ω成二次关系,即Q-a*Ω2+b;在内定-外转情况下,临界流量随转子的变化关系也为二次函数,且同样的转速,内定-外转下的流量要略大于内转-外定下的流量。研究还表明,在忽略重力影响时,转子转速和运动粘性系数对临界流量的影响可统一到无量纲的雷诺数上,且无量纲的临界流量与雷诺数呈线性关系,即Q'-k*Re。研究还发现,改变反应器的夹缝宽度比改变转子转速对临界流量的影响更大。最后,对不同倾斜角的反应器的临界流量进行了数值模拟,结果表明随着倾斜角的增大,临界流量先增大后减小,存在流量最大的临界倾斜角。研究还表明,临界倾斜角不随流体的运动粘性系数而变化,但随转子的转速而变化,此结论也证实了实验中设计的圆台倾斜角的合理性。
[Abstract]:The rotating liquid membrane reactor is a kind of micro reactor which can prepare nanometer materials such as barium sulfate by precipitation method. It is composed of two coaxial and high circular platforms, and the two tables are filled with incompressible viscous reaction fluid. In the preparation of nanomaterials, the amount of reactant (volume flow) is an appropriate value, which is called critical flow rate. The preparation process of nanomaterials is carried out under the critical flow rate, which can only be measured by experiments. In this paper, a mathematical model of fluid motion in a rotating liquid-membrane reactor is established. Combining N-S equation and appropriate boundary conditions, the critical flow rate is numerically solved, and the variation of critical flow rate with different factors is studied. In this paper, the numerical simulation of the critical flow rate under the experimental parameters is carried out. The numerical results of the critical flow rate are in good agreement with the experimental results, and the reliability of the method is verified. Then we study the influence of other parameters on the critical flow rate. The results show that at small Reynolds number, the critical flow rate Q is inversely proportional to the viscosity coefficient of the reaction fluid, that is, Q 鈭，

本文编号：1904108