Mixing In Microchannel Patterned With Superhydrophobic Surfaces

Generally, microchannels can be defined as channels having dimensions in the range of 1 µm to 1mm. The fluid flow will exhibit behaviors similar to macroscopic flows when it flows in channels of dimension more than 1mm. The flow through a microchannel network of a lab-on-a-chip device is diffusion dominant and is laminar. Mixing in microchannel cannot be carried out by exciting the liquid streams in turbulent flow to enhance its mixing performance because the Reynolds number (Re) is typically below the critical value where transition to turbulence would occur. Thus, it becomes a challenging problem for passive micromixers to mix fluids of different species within the desired range of mixing channel length in the absence of enhanced mixing techniques. In microfluidic applications, efficient mixing has been understood as one of the most fundamental and difficult-to-achieve issue. The study of mixing of fluids in microchannel laminated with superhydrophobic surface is important because there is an industrial desire to reduce the channel length and time needed for mixing of fluids for the beneficiary, especially in biomedical applications. T-type mixer is employed throughout the study and simulations show that effective mixing length increases with the fluid speed, depicted by Re number. In order to obtain efficient mixing of fluids in short residence times and mixing length, contact area for the churning of higher and lower species concentrations needs to be highly increased. Computational fluid dynamics simulations are used to determine the mixing of fluids for various microchannel designs and operating conditions during this study