Computer-Controlled Flow Cell for the Study of Particle and Drop Dynamics in Shear Flow Fields
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- 作者：Beat H. Birkhofer ; Jean-Claude Eischen ; David Megias-Alguacil ; Peter Fischer ; and Erich J. Windhab
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2005
- 出版时间：August 17, 2005
- 年：2005
- 卷：44
- 期：17
- 页码：6999 - 7009
- 全文大小：479K
- 年卷期：v.44,no.17(August 17, 2005)
- ISSN：1520-5045
文摘
Computer control for flow cells and its application for the study of droplet and particle dynamicsin shear flow conditions are presented. In the past, experimental work on single particle motionin flow has been restricted in scope by unsteady flows or by an experimental device that requiresthe operator to maintain the particle in the flow manually. The aim of this work is to retainparticles or droplets within the observation area for arbitrarily long experimental times and toapply higher shear rates than those with other comparable flow cells and control schemes. Thecontrol application considered here, using direct image analysis via a CCD camera, allows onlinecontrol of the position of the particle. A second CCD camera installed at an angle of 90
withrespect to the first camera provides additional experimental data for the full spatial observationof, e.g., drop deformation. A digital proportional-integral-differential (PID) controller wasimplemented to control the flow field. As an example, a device based on a parallel-band designwas selected to demonstrate the control scheme and its application. The design of the flow cell,the software implementation including image acquisition and analysis, digital PID control, andthe graphical user interface are described. The control scheme is designed in a way that otherflow geometries can be utilized by adjusting the PID parameters. Results from experiments onthe rotation behavior of rodlike particles (fibers) in a continuous liquid phase as well as on thedeformation of a single drop under transient shear flow are presented and discussed.
withrespect to the first camera provides additional experimental data for the full spatial observationof, e.g., drop deformation. A digital proportional-integral-differential (PID) controller wasimplemented to control the flow field. As an example, a device based on a parallel-band designwas selected to demonstrate the control scheme and its application. The design of the flow cell,the software implementation including image acquisition and analysis, digital PID control, andthe graphical user interface are described. The control scheme is designed in a way that otherflow geometries can be utilized by adjusting the PID parameters. Results from experiments onthe rotation behavior of rodlike particles (fibers) in a continuous liquid phase as well as on thedeformation of a single drop under transient shear flow are presented and discussed.