Optimal Shape Design of Pressure-Driven Curved Micro Channels with Hydrophilic and Hydrophobic Walls
S. Lim and H. Choi
School of Mechanical and Aerospace Engineering, KR
Keywords: curved micro channel, pressure drop, optimal shape design, hydrophilic wall, hydrophobic wall
In microfluidic applications such as LOC, 90-deg. and 180-deg. curved channels are frequently used to supply long flow passage in a compact volume. In most curved channels, the part connecting two straight channels is made of circular walls. However, modification of the shape in the connection part may significantly reduce the pressure loss (or the pumping power) to drive the flow, which enables us to make micro devices much smaller. In this study, we perform an optimal shape design of a pressure-driven curved micro channel with minimum pressure drop using a mathematical theory. We consider two different wall types, i.e. hydrophobic and hydrophilic walls, where the slip and no-slip conditions are applied to the first and second walls, respectively. Optimal shapes are obtained from the initial circular shapes at three different bulk Reynolds numbers of 0.1, 1 and 10 for both the 90-deg. and 180-deg. curved channels. In the optimal shape, the height of the curved channel is widened according to the optimality condition, and the pressure drop is significantly reduced by about 10%~20% as compared to that with the initial circular shape.
NSTI Nanotech 2003 Conference Technical Program Abstract