Magnetohydrodynamic Energy Harvester for Low-Power Pipe Instrumentation

Smart pipes can be adopted as a solution to problems in water distribution systems. However, the real application of such a system is usually constrained by power delivery. In this article, a magnetohydrodynamic (MHD) energy harvester for low-power pipe instrumentation is developed. A theoretical model of the maximum power output containing parameters of water conductivity, flow velocity, magnetic flux density, and water channel volume is derived. To enhance the magnetic flux density, a magnetic concentrator is designed and carefully tuned to arrange the magnetic flux as we desire and magnify the magnetic flux density within the channels. A spiral flow diverter is proposed to reconfigure the original pipe flow pattern and divert the flow into the surrounding channels to enhance the flow velocity. After integrating the proposed improvements from different fields and globally optimizing the power output, a final design is prototyped and tested in the lab, which achieves a maximum power output of 87.47 nW with a 2-m/s pipe inlet velocity. To the best of our knowledge, this is the first MHD energy harvester for low-power sensor networks. Its great potential is demonstrated, and several potential enhancements to the power output are proposed and analyzed.