Influence of defects on flow and mass transfer in the channel with micro-fluidic chips

Microfabricated pillar arrays are a new type of chromatographic columns, which can improve the performance of separation. However, because microstructure fabrication concerns many problems such as multi-scale flow, heat transfer and so on, the quality control of microstructure is quite complicated. Therefore, there is certain difference of structure parameters between design and actual till now. In the study, the effect of vacancy, damage and dimensional accuracy on flow and mass transfer is discussed. The volume averaging method is applied by the software COMSOL. Vacancy in pillar arrays can increase the reduced plate height significantly. When some micropillars are damaged, the corresponding influence on mass transfer in pillar arrays depends on the size of the missing part. When the arch height of the missing part is less than 30 % of the original diameter, the difference can be ignored. The effect could be neglected when the pillar size fluctuates within the small range. The present results would be useful for the process optimization and the design of high efficiency microstructure.