We are working to improve a new approach to harvesting electrical energy from a pressure-driven multiphase system. The Liquid-Metal Microfluidic Portable Energy Transducer (LiMMPET) is the modern, microfluidic representation of a classical Wimshurst machine. Alternating droplets of conducting and insulating fluids flowing in a serpentine microchannel capacitively interact to cause charge separation between two connected liquid metal droplets via an embedded microfabricated electrode. This novel concept was first demonstrated using a glass chip bonded to a PDMS microfluidic mold. [1]
We have since developed a finite element model using COMSOL Multiphysics to simulate the multiphase fluid dynamics and coupled electrostatic interactions between adjacent droplets and connected embedded electrodes. We used this model to improve the charge amplification factor which we define as the ratio induced charge on a droplet to the charge on an inducing droplet. [2]
We have fabricated LiMMPET devices using both soft lithographic (glass-PDMS) and conventional micromachining materials (Si-SiO2) and are now developing a fabrication process to yield totally insulating (no silicon) and robust (no PDMS) devices using SUEX.
Reference:
[1] Conner, Christopher & de Visser, Tim & Loessberg, Joshua & Sherman, Sam & Smith, Andrew & Ma, Shuo & Napoli, Mariateresa & Pennathur, Sumita & Weld, David. (2018). Energy Harvesting with a Liquid-Metal Microfluidic Influence Machine. Physical Review Applied. 9. 10.1103/PhysRevApplied.9.044008.
[2] S. MacKenzie., A. Eden, B. Dutcher, C. Meinhart, D. Huber, M. T. Napoli, D. Weld, S. Pennathur, “Improved Charge Amplification in Microfluidic Energy Harvesting Using COMSOL Simulation Software”, in Proceedings of COMSOL Conference 2019 Boston, October 2-4 2019, Boston, MA.