Rotational flows and mixing enhancement

旋转流和混合增强

• 批准号: EP/E055958/1
• 负责人: Andrea Ducci
• 金额: $ 68.11万
• 依托单位: King's College London
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FE055958%2F1
• 关键词: Rotational; flows; mixing; enhancement

The proposed research study aims at investigating rotationally induced flows in cylindrical geometries to bring new insight on the type, nature and occurrence of flow transitions and instabilities as well as to offer novel information to better understand mixing mechanisms in related equipment and therefore develop and improve mixing modelling.Mixing is a physical phenomenon that is often encountered in everyday life. One of the simplest example is that of a spoon stirring a coffee cup to blend milk. Numerous applications can be found in the chemical and biochemical industries that utilise mixing of two or more phases or reactants.From this point of view several reactor designs can be distinguished that attain mixing in different ways: oscillatory flow mixers (OFM), static mixers, stirred vessels and shaking flasks. The last two types of reactors are rotationally induced mixing reactors for which a flow is generated by a stirring impeller or by the movement of the tray holding a cylindrical container along a circumferential orbit. The analogy between these two types of reactors is even more evident when considering that shaking flasks are often small scale mixers employed in the early stage of bioprocess development, before the developed process is implemented in a large scale industrial stirred tank.However, while the fluid mechanics of stirred tank reactors have been extensively studied, little is known about the flow patterns, flow transitions and instabilities taking place in shaken flasks. The consequences of this lack of knowledge are twofold: (a) a process developed in the shaken flasks cannot be fully characterised, undermining its reproducibility; (b) its operating conditions cannot be properly correlated to those present in industrial, scaled up reactors, usually stirred tanks, for which a vast amount of data is available in literature.Taking into account the differences in the flow geometry, certain types of instability and unsteadiness that are documented in the few papers dealing with fluid mechanics in shaken flasks, recall those that are encountered in a cylindrical container with a rotating endwall for which data is available in literature. The similarity between the two systems (i.e. shaking flask of cylindrical shape, and cylindrical container) is also indicated by the fact that the movement of the shaken flask can be seen as the superimposition of the rotating movement of a cylinder around its axis and a counter rotating orbital movement of the cylinder itself around an eccentric axis. The first type of movement is in fact very similar to that of a cylindrical container with a rotating endwall.Therefore the present research proposal has been formulated in three sets of experiments that will be carried in flows induced by three different types of rotational movements in a cylindrical container.On the one hand this methodology, with an analogy between three different flows investigated in the same geometry, should provide an original way to understand better the occurrences of flow instability and transitions from a general point of view, and will enable to assess the physical mechanisms determining mixing. On the other hand the present investigation aims at determining relevant parameters based on fluid mechanics aspect that will facilitate the process of scale up/down between stirred tank reactors and shaken flasks.

该研究旨在研究圆柱形几何形状中的旋转诱导流动，以提供有关流动转变和不稳定性的类型，性质和发生的新见解，并提供新信息，以更好地了解相关设备中的混合机制，从而开发和改进混合模型。混合是日常生活中经常遇到的物理现象。一个最简单的例子是勺子搅拌咖啡杯来混合牛奶。在化学和生物化学工业中，有许多应用是利用两相或多相反应物的混合。从这个角度来看，可以区分几种反应器设计，它们以不同的方式实现混合：振荡流混合器（OFM），静态混合器，搅拌容器和摇瓶。最后两种类型的反应器是旋转诱导混合反应器，对于该反应器，通过搅拌叶轮或通过保持圆柱形容器的托盘沿圆周轨道沿着运动来产生流。当考虑到摇瓶通常是在生物工艺开发的早期阶段使用的小规模混合器时，这两种类型的反应器之间的相似性甚至更加明显，在开发的工艺在大规模工业搅拌槽中实施之前。然而，尽管搅拌槽反应器的流体力学已经被广泛研究，但对流动模式知之甚少，在摇瓶中发生流动转变和不稳定性。缺乏知识的后果是双重的：（a）在摇瓶中开发的过程无法完全表征，破坏了其可重复性;（B）它的操作条件不能与工业放大反应器（通常是搅拌槽）中存在的操作条件适当地相关，对于这些反应器，大量的数据可在文献中获得。在涉及摇瓶中的流体力学的少数论文中记载的某些类型的不稳定性和不稳定性，使人想起在具有旋转端壁的圆柱形容器中遇到的那些不稳定性和不稳定性，其数据可在文献中获得。两个系统（即圆柱形摇瓶和圆柱形容器）之间的相似性也由以下事实表明：摇瓶的运动可以被视为圆柱体围绕其轴线的旋转运动和圆柱体本身围绕偏心轴线的反向旋转轨道运动的叠加。第一种类型的运动实际上与具有旋转端壁的圆柱形容器的运动非常相似。因此，本研究建议在三组实验中进行，这些实验将在圆柱形容器中由三种不同类型的旋转运动引起的流动中进行。一方面，这种方法，在相同几何形状下研究的三种不同流动之间进行类比，应该提供一个原始的方法，更好地理解流动不稳定性和过渡的发生，从一般的角度来看，并将能够评估的物理机制，确定混合。另一方面，本研究的目的是确定相关参数的基础上，流体力学方面，这将有助于放大/缩小的过程之间的搅拌釜反应器和摇瓶。

项目成果

Assessment of Flow Dynamics Before and After Implantation of Transcatheter Aortic Valves

经导管主动脉瓣植入前后的流动动力学评估

• 作者: Andrea Ducci (Author)

Strain dynamics for vortex ring mixing process

涡环混合过程的应变动力学

• 作者: Andrea Ducci (Author)

On the interaction of trailing and macroinstability vortices in the vicinity of a stirred vessel impeller

关于搅拌容器叶轮附近尾随涡流和宏观不稳定涡流的相互作用

• 作者: Andrea Ducci (Author)

APPRAISAL OF SHAKEN BIOREACTOR MIXING EFFICIENCY FOR DIFFERENT OPERATING CONDITIONS

不同操作条件下摇动生物反应器混合效率的评估

• 作者: Andrea Ducci (Author)

ON THE FLUID AND MIXING DYNAMICS OF ORBITALLY SHAKEN BIOREACTORS

关于轨道振动生物反应器的流体和混合动力学

• 作者: Andrea Ducci (Author)