TY - JOUR

T1 - A Water Monitoring System for Proton Exchange Membrane Fuel Cells Based on Ultrasonic Lamb Waves

T2 - An Ex-Situ Proof of Concept

AU - Dou, Zehua

AU - Fang, Bowen

AU - Tropf, Laura

AU - Hoster, Harry

AU - Schmidt, Hagen

AU - Czarske, Jürgen

AU - Weik, David

PY - 2023/11/3

Y1 - 2023/11/3

N2 - Up to date, the efficiencies of proton exchange membrane fuel cells (PEMFCs) are limited by the water flooding issue. Water monitoring systems, which are a crucial step to overcoming these flooding-related problems, are mostly either invasive or compromise on the temporal resolution and field of view. Thus, we propose an ultrasonic-Lamb-waves-based, real-time, and nondestructive water monitoring system. Briefly, ultrasonic transducers are mounted on the back side of bipolar plates (BPPs) exciting Lamb waves along flow channels incorporated in BPPs. Echo signals from water droplets in the channels are also received by the transducers. Thus, with the knowledge of Lamb wave propagation velocity, water droplets are spatially resolved by the time of flight of each droplet echo. Meanwhile, the energy of each droplet-induced echo wave packet is used to quantify the local flooding status. We have implemented a flexible and generic system adaptable to various flow field designs. The working principle was demonstrated for ex situ conditions with a BPP with a 25-cm2 active area. A water sensitivity of at least 50 nL was realized, allowing for studying droplet and slug flows in PEMFCs. A 1.3-mm spatial resolution and a 2-kHz temporal resolution were simultaneously achieved. The high-performance water monitoring opens new horizons to study dynamic water evolution in channels of PEMFCs using cost-effective instrumentation, which may pave the way toward more efficient high-power PEMFCs with increased lifetimes.

AB - Up to date, the efficiencies of proton exchange membrane fuel cells (PEMFCs) are limited by the water flooding issue. Water monitoring systems, which are a crucial step to overcoming these flooding-related problems, are mostly either invasive or compromise on the temporal resolution and field of view. Thus, we propose an ultrasonic-Lamb-waves-based, real-time, and nondestructive water monitoring system. Briefly, ultrasonic transducers are mounted on the back side of bipolar plates (BPPs) exciting Lamb waves along flow channels incorporated in BPPs. Echo signals from water droplets in the channels are also received by the transducers. Thus, with the knowledge of Lamb wave propagation velocity, water droplets are spatially resolved by the time of flight of each droplet echo. Meanwhile, the energy of each droplet-induced echo wave packet is used to quantify the local flooding status. We have implemented a flexible and generic system adaptable to various flow field designs. The working principle was demonstrated for ex situ conditions with a BPP with a 25-cm2 active area. A water sensitivity of at least 50 nL was realized, allowing for studying droplet and slug flows in PEMFCs. A 1.3-mm spatial resolution and a 2-kHz temporal resolution were simultaneously achieved. The high-performance water monitoring opens new horizons to study dynamic water evolution in channels of PEMFCs using cost-effective instrumentation, which may pave the way toward more efficient high-power PEMFCs with increased lifetimes.

KW - Electrical and Electronic Engineering

KW - Instrumentation

U2 - 10.1109/tim.2023.3329101

DO - 10.1109/tim.2023.3329101

M3 - Journal article

VL - 72

JO - IEEE Transactions on Instrumentation and Measurement

JF - IEEE Transactions on Instrumentation and Measurement

SN - 0018-9456

M1 - 9601112

ER -