基于康达效应的核用微型萃取器的性能研究

发布时间：2018-02-20 20:23

本文关键词： 液液萃取 Purex流程微混合器康达效应　出处：《清华大学》2015年硕士论文　论文类型：学位论文

【摘要】：伴随我国核电事业的迅速发展,从经济型和安全性方面考虑,必须对乏燃料进行后处理。目前,国际上普遍采用的乏燃料后处理工艺Purex工艺中被广泛使用的萃取设备均存在不同程度的缺憾。相比于上述传统设备,微萃取设备具有混合效率高、设备尺度小,比表面积大,传质性能好、停留时间短,设备内存留物料少等特点,非常符合Purex工艺的要求,发展前景广阔。本文针对基于康达效应的核用微型萃取器中两相的混合传质、富集与级间转运问题进行研究,提出了一种高效的多级逆流微型萃取器的设计方案。针对液液混合,本文利用流体力学中的康达效应(Coanda effect),即射流附壁效应构造出一种新型被动式反馈振荡微混合器,通过互溶液体混合实验,揭示了被动式反馈振荡微混合器中的三种不同混合机理:涡流混合、内部再循环混合与流体振荡;分析了非对称反馈通道和分流体结构对于提升被动式振荡反馈微混合器性能的重要意义;通过数字图像处理方法对混合性能进行了定量的验证,展现了被动式振荡反馈微混合器在高Re数、高通量领域的广泛应用前景。进一步对新型被动式反馈振荡微混合器的不互溶两相液体混合特性进行研究,本文发现了其在不同Re数下的四种液液两相流型,并考察了两种被动式反馈振荡微混合器在硝酸/TBP体系与Zr4+/TBP体系中的萃取传质性能,验证了被动式反馈振荡微混合器在高Re数下优异的萃取性能。以新型多级被动式反馈振荡微混合器为基础,本文提出通过控制循环操作方法实现两相混合传质、富集与级间转运的微型萃取器设计方案并进行了验证,成功实现了多级逆流萃取操作,对Zr4+萃取效率是并流设备的2-4倍,在Purex流程中有良好的潜在而广泛的应用前景。通过计算流体力学模拟,本文进一步讨论了新型被动式反馈振荡微混合器内三种混合机理的产生与联系,证明了其流体振荡频率与Re数成正比的关系,为进一步对微混合器进行结构与性能优化奠定了理论基础。
[Abstract]:Along with the rapid development of China's nuclear power industry, considering economy and security, must carry on the spent fuel postprocessing. At present, widely used by the international spent fuel postprocessing extraction equipment is widely used in Purex process technology have different degrees of defects. Compared to the traditional equipment, micro extraction equipment has high mixing efficiency, small scale equipment, large surface area, good mass transfer performance, short residence time, the characteristics of equipment retention less material, very much in line with the requirement of Purex technology, development prospect is broad. According to the mass transfer in two-phase micro extractor with Coanda effect based on nuclear research, enrichment and transfer problem between and put forward a design scheme of efficient multistage countercurrent extractor. The micro liquid mixture, using Coanda effect in fluid mechanics (Coanda effect), namely the jet wall attachment effect is constructed A new type of passive feedback oscillation micro mixer, the miscible liquid mixing experiments revealed three different mixing mechanism of passive feedback oscillation in the micromixer: eddy mixing, internal recirculation is mixed with the fluid oscillation; analysis of asymmetric feedback channel and shunt structure is important for improving the passive micromixer performance feedback oscillation; based on the mixing performance of the quantitative verification of digital image processing method, show the passive feedback oscillation micro mixer at high Re number, high throughput potential applications. Further feedback oscillation of new passive micromixer immiscible liquid two-phase mixing characteristics were studied in this paper, found in different Re number four a liquid-liquid two-phase flow pattern, and the effects of two kinds of passive feedback oscillation extraction of micro mixer in nitrate /TBP system and Zr4+/TBP system. To verify the extraction performance of passive micromixer feedback oscillation in high Re number is excellent. The new multi passive micromixer based feedback oscillation, this paper through the control method of operation to achieve the two-phase mass transfer, micro extractor enrichment and transfer among the level design and verified, the successful implementation of the multistage countercurrent extraction the operation of Zr4+, the extraction efficiency is 2-4 times and the flow of equipment, in the Purex process has a good potential and wide application prospect. Through CFD simulation, this paper further discusses the generation and contact model passive feedback oscillation micro mixer three hybrid mechanism, proved its relationship with the frequency of fluid oscillation Re is proportional to the number of the laid a theoretical foundation for further optimization of structure and performance of micro mixer.

【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TL24;TQ051.83

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