逆流反应器中纳米材料连续热液流动合成过程建模与仿真

利用计算流体动力学的数值模拟来研究超临界水操作条件下,用于纳米材料合成的连续热液系统中的逆流反应器的性能.入口流量和温度是关键过程变量并在仿真过程中发生变化.预测的温度与取自相同的设计和在相同操作条件下的实验室测量数据相吻合.研究发现反应器中物料的快速混合可以通过超临界水的高流量与高入口温度,和使用非平衡的入口流量条件即超临界水的流量不等于反应物流量来实现.对比仿真还显示内管插入长度是一个反应器性能的关键控制因素,当前反应器配置下其必须小于72.5mm,以达到令人满意的混合效果.

Modeling and simulation of counter-current reactors for continuous hydrothermal flow synthesis of nanoparticles

Numerical simulation using computational fluid dynamics is carried out to study the performance of a counter-current reactor in a continuous hydrothermal system for nanomaterial synthesis that is operated under supercritical water condition. Inlet flowrate and temperature are the key process variables and vary in the simulation. The predicted temperatures are in good agreement with measurements taken from a laboratory rig of identical design and under the same operating conditions. It is found that fast mixing in the reactor can be achieved by high inlet temperature, high inlet flowrate of the supercritical water and using unbalanced flow conditions, i.e. the supercritical water flowrate should not be equal to that of the precursor. The comparative simulation also reveals that the insertion length of the inner tube is a key factor dictating the reactor performance, and it needs to be less than 72.5 mm in order to achieve satisfactory mixing under the current reactor configuration.