基于被动式反馈振荡微混合器的多级逆流微萃取系统

Due to radioactivity, the perfect extractors for spent fuel reprocessing should have no-moving parts, a small effective volume, and a high mass transfer rate. However, there is no such perfect extractor available today. In this application, a novel micro-extraction system is proposed to solve the challenge how passive micromixers are used for high-throughput countercurrent extractions. Two key problems have to be solved in this application. The first is to design a passive chaotic advection micromixer for high-throughputs. A bidirectional and feedback oscillating micromixer is proposed, in which a fluidic oscillation occurs. The oscillation is caused from the wall-attachment flow effect and produces transverse flows that can form an efficient and unsteady chaotic advection. Two immiscible liquids are effectively mixed and efficient mass transfer can be realized. The second key problem is how to realize multiple-stage countercurrent flow between two immiscible liquids, including the phase separation. This is achieved by using the action of gravity and electric coalescence, and the novel pulse-feeding. The hydrodynamic characteristics and mass transfer performance of the single-stage and multiple-stage countercurrent microextractors are investigated by the factor experiments, computational fluid dynamics simulation, and extraction experiments. The novel micro-extraction system can meet the best design criteria.

由于放射性，核电乏燃料后处理中的萃取设备以无可动部件、小容积和高传质效率为最佳设计原则，但迄今尚无“完美”的萃取设备。本申请提出了一个新颖的多级逆流微萃取系统，可解决迄今从未被解决的难题——被动式微混合器如何被用于以生产为目标的逆流萃取操作。两个关键问题得到解决：（1）高通量、高效的液液混合器——双向被动式反馈振荡微混合器。该微混合器利用附壁流动效应在振荡腔内形成周期振荡，产生的非定常横向流动可在层流下形成混沌对流混合，从而实现高通量下的相间高效传质；（2）包括相分离在内的多级逆流操作——利用重力和电聚并使分散相液滴快速聚并而分相，同时结合独特的脉冲进料实现微通道中的两相逆流流动。本申请通过因素影响实验、计算流体力学模拟、示踪技术和萃取实验等方法对该新型微萃取器的单级和多级结构的水力学特征和传质性能进行研究。提出的微萃取系统是一种非常规的传质设备，可满足乏燃料后处理萃取设备的最佳设计原则。

由于放射性，核电乏燃料后处理中的萃取设备以无可动部件、小容积和高传质效率为最佳设计原则，但迄今尚无“完美”的萃取设备。本申请首创了一个新颖的混合式逆流微萃取系统，可解决迄今从未被解决的难题——如何在微尺寸下实现被动式逆流微萃取，解决了两个关键问题：（1）发明了适用于逆流微萃取的、高通量液液微混合器——双向被动式反馈振荡微混合器。该微混合器利用附壁流动效应在振荡腔内形成周期振荡，产生的非定常横向流动可在层流下形成混沌对流混合，从而实现了高通量下的相间高效传质；（2）提出了新型多级逆流操作方法——利用级间集成的一体化微型沉降器实现分散相液滴的快速聚并而分相，同时结合独特的脉冲进料实现了微通道中的两相逆流流动。本申请通过因素影响实验、示踪技术和萃取实验等方法对该新型微萃取器的单级和多级结构的水力学特征和传质性能进行了研究,证明该新型逆流微萃取系统具有通量大、效率高、全被动式操作的优点，在乏燃料后处理以及其它化工、生物制药等领域具有极大的应用潜力。