Microchannel plate geometry optimization for even flow distribution at high flow rates

Microreactors generally consist of microstructured plates contg. a large no. of equal channels. The small diam. of the channels enables high heat and mass transfer rates. To exploit this feature and realize a high throughput within a small vol., it is necessary to use high flow rates. However, at these high flow rates it is not straightforward to obtain an even distribution of fluid flow over the individual microchannels. A three-dimensional computational fluid dynamics (CFD) model was used to calc. the flow distribution on a microstructured plate. Calcn. time was reduced by introducing an artificial viscosity in the channel region. The calcns. show that a transitional velocity exists, below which the flow distribution is independent of velocity and above which inertia effects start to influence the distribution. To optimize the flow distribution, nine different plate geometries were studied at flow rates between 0.1 and 100 ms-1, or 4 * 10-4 to 0.4 m3h-1 per plate. By optimizing the plate geometry, the relative std. deviation of the flow distribution was reduced from 19 to 3%. Furthermore, it is shown that the optimal geometry depends on the flow rate, which thus needs to be taken into account in the design of microchannel plates. [on SciFinder (R)]