Characterizing dynamic hysteresis and fractal statistics of chaotic two-phase flow and application to fuel cells
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)
In this study, we analyze the stability of two-phase flow regimes and their transitions using chaotic and fractal statistics, and we report new measurements of dynamic two-phase pressure drop hysteresis that is related to flow regime stability and channel water content. Two-phase flow dynamics are relevant to a variety of real-world systems, and quantifying transient two-phase flow phenomena is important for efficient design. We recorded two-phase (air and water) pressure drops and flow images in a microchannel under both steady and transient conditions. Using Lyapunov exponents and Hurst exponents to characterize the steady-state pressure fluctuations, we develop a new, measurable regime identification criteria based on the dynamic stability of the two-phase pressure signal. We also applied a new experimental technique by continuously cycling the air flow rate to study dynamic hysteresis in two-phase pressure drops, which is separate from steady-state hysteresis and can be used to understand two-phase flow development time scales. Using recorded images of the two-phase flow, we show that the capacitive dynamic hysteresis is related to channel water content and flow regime stability. The mixed-wettability microchannel and in-channel water introduction used in this study simulate a polymer electrolyte fuel cell cathode air flow channel.
- OSTI ID:
- 22599006
- Journal Information:
- Physics of Fluids, Journal Name: Physics of Fluids Journal Issue: 5 Vol. 28; ISSN 1070-6631; ISSN PHFLE6
- Country of Publication:
- United States
- Language:
- English
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