Taylor Annette F, Britton Melanie M
Department of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom.
Chaos. 2006 Sep;16(3):037103. doi: 10.1063/1.2228129.
Magnetic resonance imaging (MRI) provides a powerful tool for the investigation of chemical structures in optically opaque porous media, in which chemical concentration gradients can be visualized, and diffusion and flow properties are simultaneously determined. In this paper we give an overview of the MRI technique and review theory and experiments on the formation of chemical waves in a tubular packed bed reactor upon the addition of a nonlinear chemical reaction. MR images are presented of reaction-diffusion waves propagating in the three-dimensional (3D) network of channels in the reactor, and the 3D structure of stationary concentration patterns formed via the flow-distributed oscillation mechanism is demonstrated to reflect the local hydrodynamics in the packed bed. Possible future directions regarding the influence of heterogeneities on transport and reaction are discussed.
磁共振成像（MRI）为研究光学不透明多孔介质中的化学结构提供了强大工具，在这种介质中可以可视化化学浓度梯度，并同时确定扩散和流动特性。在本文中，我们概述了MRI技术，并回顾了在添加非线性化学反应后，管式填充床反应器中化学波形成的理论和实验。展示了反应扩散波在反应器三维（3D）通道网络中传播的磁共振图像，并证明了通过流动分布振荡机制形成的静态浓度模式的3D结构反映了填充床中的局部流体动力学。讨论了关于非均质性对传输和反应影响的未来可能方向。
