A miniature pneumatic energy generator using Kármán vortex street

□A pneumatic energy generator for harnessing energy from Kármán vortex street is presented.□Tandem arrangement of triangular bluff bodies to enhance pressure fluctuation in the vortex street.□14 m Vp is generated with pressure amplitude of 70 Pa and frequency 872 Hz in the vortex street.

A proof-of-concept of a miniature pneumatic energy generator for harnessing energy from Kármán vortex street behind bluff bodies is presented. It converts flow energy into electrical energy by piezoelectric conversion with oscillation of a piezoelectric film. The tandem arrangement of the bluff bodies is designed to enhance the amplitude of the pressure fluctuation in the vortex street, which vibrates the piezoelectric film. Prototypes of the energy generator are fabricated and tested. Experimental results show that an open circuit output voltage of 14 m Vp and an average output power of 0.59 nW are generated when the pressure oscillates with an amplitude of nearly 70 Pa and a frequency of about 872 Hz. This energy harvesting approach has the potential of converting the flow energy of compressed air in a pipeline into electricity for powering wireless sensing devices. Future design guidelines for increasing the electrical power output are suggested based on analyses.