Towards high resolution monitoring of water flow velocity using flat flexible thin mm-sized resistance-typed sensor film (MRSF)

Zhiheng Xu; Yingzheng Fan; Tianbao Wang; Yuankai Huang; Farzaneh MahmoodPoor Dehkordy; Zheqin Dai; Lingling Xia; Qiuchen Dong; Amvrossios Bagtzoglou; Jeffrey McCutcheon; Yu Lei; Baikun Li

doi:10.1016/j.wroa.2019.100028

Towards high resolution monitoring of water flow velocity using flat flexible thin mm-sized resistance-typed sensor film (MRSF)

Water Res X. 2019 Apr 10:4:100028. doi: 10.1016/j.wroa.2019.100028. eCollection 2019 Aug 1.

Affiliations

¹ Department of Civil & Environmental Engineering, University of Connecticut, Storrs, Connecticut, 06269, United States.
² School of Energy and Environment, Southeast University, Nanjing, Jiangsu, 210096, China.
³ Department of Chemical & Biomolecular Engineering, University of Connecticut, Storrs, Connecticut, 06269, United States.

Abstract

Novel flexible thin mm-sized resistance-typed sensor film (MRSF) fabricated using ink-jet printing technology (IPT) was developed in this study to monitor water flow rate in pipelines in real time in situ mode. The mechanism of MRSF is that the mm-sized interdigitated electrodes made by printing silver nanoparticles on an elastic polyimide film bend under different flow rates, leading to variation of the resistance of the sensor at different degrees of curvature. Continuous flow tests showed that MRSF possessed a high accuracy (0.2 m/s) and excellent sensitivity (0.1447/ms^-1). A model of sensor resistance and flow velocity was established to unfold the correlation between the fundamentals of fluid mechanics and the mechanic flexibility of sensor materials. An analytical model yielded a high coefficient of determination (R² > 0.93) for the relationship between the resistance increment of the MRSF and the square of the flow velocity at the velocity range of 0.25-2 m/s. Furthermore, a temperature-correction model was developed to quantify the effect of water temperature on the sensor resistance readings. MRSF exhibited a low temperature coefficient of resistance (TCR, 0.001) at the water temperature range of 20-60 °C. Computational fluid dynamics (CFD) simulations using the finite element method were conducted and confirmed both the underlying load assumptions and the deformation characteristics of the sensor film under various flow and material conditions. High-resolution monitoring of water flow rate using MRSF technology was expected to save at least 50% energy consumption for a given unit, especially under flow fluctuation. MRSF possesses a great potential to perform real-time in situ monitoring at high accuracy with ultralow cost, thus enabling the feedback control at high spatiotemporal resolution to reduce the overall energy consumption in water and wastewater systems.

Keywords: Computational fluid dynamics simulations; Flow velocity; Kapton film flexibility; Mm-sized resistance type sensor film (MRSF); Real-time in situ monitoring; Temperature correction.