On the use of submerged piezoelectric MFCs for dual viscosity sensing and energy harvesting

Abstract

We demonstrate the potential of unimorph beams equipped with macro fiber composites to integrate viscosity sensing and energy harvesting functionalities into a single device. The viscosity sensing component involves measuring the quality factor and resonance frequency peak associated with the second out-of-plane mode of vibration. We showcase the suitability of the present sensing device for liquids of wide range of kinematic viscosities from 1 to 1543.5 cSt. Following the quality factor-based sensing approach, the sensor reached a sensitivity of S = −0.0019/cSt. The amplitude-based sensing mechanism demonstrated a sensitivity of S = −3.3 mV/cSt. The viscosities of motor oil and glycerin, determined using the generated calibration curves, are found in close agreement with those obtained from a conventional rotational viscometer. The proposed sensing device holds great promise for online viscosity measurement, particularly for high-viscosity fluids, simple design, ease of operation, and partial self-sensing capability, thanks to energy harvesting.