Numerical and experimental analysis of an acoustic micropump utilizing a flexible printed circuit board as an actuator

We present the design of a microfluidic pumping device based on the effect of boundary layer driven acoustic streaming. One wall of the channel is made from a flexible material and hosts a flexural travelling wave, which induces a directed flow of the fluid inside the channel. A flexible printed circuit board was chosen as the oscillating wall, which makes the manufacturing process easy and could potentially enable the fabrication of low-cost disposable devices for the use in e.g. biomedical applications. Numerical studies based on an approach utilizing perturbation theory were conducted, where a comparison with the result of a time-dependent simulation of the full Navier-Stokes equations is provided. Based on the numerical analysis, a quadratic dependency of the flow velocity on the deflection amplitude of the membrane was identified. A ring-shaped membrane and channel were considered to be most practical for the experimental setup, where the idea and design process will be discussed. The flow velocity was measured using particle tracking velocimetry and the results show the same quadratic dependency of the flow velocity, which is in agreement with the theory.