撞击流反应器制备纳米铜粉过程的流场多尺度分析

来源期刊:中国有色金属学报2016年第3期

论文作者:罗燕 周剑秋 郭钊 周玉新 郭嘉 杨侠

文章页码:630 - 636

关键词:撞击流反应器;纳米铜粉;流场;多尺度分析;数值模拟

Key words:impinging stream reactor; nanometer copper powder; flow field; multi scale analysis ;numerical simulation

摘    要:在撞击流技术制备纳米铜粉的实验反应体系中,粒径的分布规律与流场混合尺度存在某种联系。采用数值计算方法,从流场多尺度角度开展液体连续相撞击流反应器(LISR)强化制备过程分析。结果表明:大尺度流体对流由桨叶旋转带动,中等尺度湍流扩散强度与湍黏度和速度梯度关联,小尺度流体黏性扩散与中等尺度湍流扩散类似;LISR为制备纳米铜粉反应体系提供一个强烈压力波动区,其微观状态下的反应体系随着压力波动区能量的传递和转换得以迅速实现,并显著促进制备纳米铜粉反应过程的进行;LISR中湍黏扩散作用显著,能高效促进流体更加均匀,有利于制备纳米铜粉反应体系。上述过程流场的多尺度分析,对后期撞击流技术制备纳米铜粉的实验反应体系工艺优化具有指导意义。

Abstract: In the experiment system of preparing nano-copper powder in impinging stream reactor, there is an association between particle size distribution and flow mixing scale. The strengthened preparation process in liquid-continuous impinging streams reactor (LIRS) was analyzed by numerical computation from multi-scale standpoint. The results show that the large-scale convection is driven by rotating blades, the medium-scale turbulence diffusion intensity and turbulent viscosity are associated with velocity gradient,and small-scale viscosity diffusion is similar with that of medium-scale turbulent diffusion. LISR provides the reaction system with a strong pressure fluctuation zone, in which the micro reaction system can quickly be realized and promoted with the energy transfer and conversion. The remarkable turbulent viscous diffusion can effectively accelerate the fluid more uniform and be conducive to the reaction system. The multi-scale analysis of the flow field above has guiding significance for the optimization of the latter preparing of the impinging stream technology of nano-copper powder reaction system.

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