Numerical simulation of microfluidic injection processes in crossing microchannels

The design and operation control of microfluidic devices have drawn a great deal of attention over the last decade due to the emerging lab-on-a-chip applications. Cross-shaped microchannels connecting liquid reservoirs are typical configurations of the microfluidic chips. Normally the microchannels have a large length-to-width aspect ratio (typically 1500:1), therefore, the transport phenomena in these microchannels are essentially multiscale and multidimensional problems. There are no analytical solutions existing for such kind of problems and it has been found that effectively and efficiently simulating the transport phenomena in such microchannels is very difficult. A numerical model developed here uses the designed boundaries to truncate the physical domain to a small computation domain in order to concentrate computing power in the areas exhibiting multidimensional phenomena (such as intersections) and apply analytical functions in the areas of one-dimensionality (such as fully developed flow region). This model is employed to simulate the flow and mass transport processes in a planar glass chip with a cross-shaped microchannel, and the model predictions are compared to the experimental results. Agreement between the model predictions and experimental results verified that this newly developed model is capable of accurately and efficiently simulating the transport phenomena in microfluidic devices.