Naslov
Autonomous solutions for powering wireless sensor nodes in rivers

Autori
Kamenar, Ervin ; Maćešić, Senka ; Gregov, Goran ; Blažević, David ; Zelenika, Saša ; Marković, Kristina ; Glažar, Vladimir

Izvornik
Proceedings of SPIE, the International Society for Optical Engineering (0277-786X) 9517 (2015); 951712-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
wireless networks ; pollution sensors ; miniature hydro-generators ; piezoelectric energy harvesting

Sažetak
A need for enabling autonomous powering of wireless sensor network nodes is evident today. Sensor nodes may be placed in locations hard to access and powered via batteries of limited lifetime. Different energy harvesting principles allow to overcome these limitations. Energy harvesting concepts designed for sensor nodes to be placed in watercourses, are explored in this work: a miniaturized underwater turbine, a ‘piezoelectric eel’ and a hybrid turbine solution coupled with a rigid piezoelectric beam. The foreseen autonomous sensor nodes are to be placed 0.5 m from the bottom of the river and used for measuring pollutants’ concentration in the river flow. The miniaturized underwater hydro- generator, designed in a 3D modelling software, is based on a DC generator enclosed in a watertight enclosure. The electronics used to adapt the voltage levels to the employed sensors is designed and manufactured. Laboratory and river experiments are conducted showing that the achieved power levels are compatible with the foreseen application. The piezoelectric eel is a composite flag-like compliant device made of two layers of piezoelectric polymer PVDF, a substrate layer and electrodes placed on PVDF’s surface layer. A bluff body induces Karman vortexes coercing the eel to move in a flapped motion. A custom software, where fluid flow is modelled using Navier-Stokes equations, while the eel is modelled as a massless beam interacting with the fluid, and a second massive beam, which is connected to the first one via stiff springs, is developed in C++. The eel is prototyped and its performances are experimentally assessed. The third proposed harvesting configuration is a solution based on ‘plucking’ a rigid piezoelectric cantilever by means of fulcrums protruding from propeller’s shaft and then allowing it to vibrate freely thus generating electrical charge. The concept is modelled via a finite element model in a transient analysis routine.

Izvorni jezik
Engleski

Znanstvena područja
Strojarstvo, Temeljne tehničke znanosti, Interdisciplinarne tehničke znanosti

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