Magnetic resonance imaging of flow-distributed oscillations.
Magnetic resonance imaging of flow-distributed oscillations.
复制标题
流动分布振荡的磁共振成像。
DOI：
10.1021/jp053063i
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
L. Gladden
中科院分区：
文献类型：
--
作者：
M. Britton;A. Sederman;A. Taylor;S. Scott;L. Gladden
利用磁共振成像（MRI）研究了在硫酸-磷酸混合介质中，锰催化的Belousov-Zhabotinsky（BZ）反应在填充床反应器（PBR）中稳态浓度模式的形成. PBR由填充有玻璃珠的柱组成，其通过连续搅拌釜式反应器（CSTR）进料。由于反应器是光学不透明的，这些反应-扩散-平流波的三维（3D）结构的调查是不可能使用传统的图像捕获技术。利用磁共振成像（MRI）对该系统进行了探测，并对这些波的形成、三维结构和发展进行了研究。在反应堆启动时，观察到行波。经过这个初始阶段后，波浪稳定下来，变得静止。一旦固定，它们被发现非常稳定。有显着的异质性的反应前沿，这是不平坦的，因为将预期从活塞流反应器。相反，由于床的局部流体动力学，特别是较高的速度，因此靠近反应器壁的停留时间较短，观察到反应波前的形状是圆锥形的。
The formation of stationary concentration patterns in a packed-bed reactor (PBR), using a manganese-catalyzed Belousov-Zhabotinsky (BZ) reaction in a mixed sulfuric-phosphoric acid medium, was studied using magnetic resonance imaging (MRI). The PBR was composed of a column filled with glass beads, which was fed by a continuous stirred tank reactor (CSTR). As the reactor is optically opaque, investigation of the three-dimensional (3D) structure of these reaction-diffusion-advection waves is not possible using conventional image capture techniques. MRI has been used to probe this system and the formation, 3D structure, and development of these waves has been studied. At reactor startup, traveling waves were observed. After this initial period the waves stabilized and became stationary. Once fixed, they were found to be remarkably stable. There was significant heterogeneity of the reaction fronts, which were not flat, as would be expected from a plug-flow reactor. Instead, the reaction wave fronts were observed to be conical in shape due to the local hydrodynamics of the bed and specifically the higher velocities and therefore lower residence times close to the wall of the reactor.