Microchannel Surface Structures for Drag Reduction

There are many different designs of microchannels for fluid transport or heat transfer purposes. The most challenging problem is selecting the shape and boundary structure of the microchannel walls so that they meet all the requirements and be most optimal and efficient at high flow rates. Various studies show that applying superhydrophobic surface to the microchannel walls can significantly reduce drag forces; however, the characteristics of the best surface structure for a superhydrophobic boundary condition are still unknown. To clarify this problem, we have reviewed different possible engineering solutions for surface structure options, their effect on reducing microchannel drag, and compared them in the present paper.