Strong enhancement of streaming current power by application of two phase flow.

We show that the performance of a streaming-potential based microfluidic energy conversion system can be strongly enhanced by the use of two phase flow. Injection of gas bubbles into a liquid-filled channel increases both the maximum output power and the energy conversion efficiency. In single-phase systems the internal conduction current induced by the streaming potential limits the output power, whereas in a two-phase system the bubbles reduce this current and increase the power. In our system the addition of bubbles enhanced the maximum output power of the system by a factor of 74 and the efficiency of the system by a factor of 163 compared with single phase flow.