Gas-liquid two-phase flow behaviors and performance characteristics of proton exchange membrane fuel cells in a short-term microgravity environment

Abstract

h i g h l i g h t sMicrogravity experiments are operated at lower temperature. Channel orientations affect the performance of PEMFCs in a microgravity environment. Water in vertical channels is easily expelled in microgravity environment. Gravity slightly affects the two-phase flow behaviors of PEMFCs with horizontal channels. In this work, proton exchange membrane fuel cells (PEMFCs) with transparent windows are designed to study the gas-liquid two-phase flow behaviors inside flow channels and the performance of a PEMFC with vertical channels and a PEMFC with horizontal channels in a normal gravity environment and a 3.6 s short-term microgravity environment. Experiments are conducted under high external circuit load and low external circuit load at low temperature where is 35 C. The results of the present experimental work demonstrate that the performance and the gas-liquid two-phase flow behaviors of the PEMFC with vertical channels exhibits obvious changes when the PEMFCs enter the 3.6 s short-term microgravity environment from the normal gravity environment. Meanwhile, the performance of the PEMFC with vertical channels increases after the PEMFC enters the 3.6 s short-term microgravity environment under high external circuit load, while under low external circuit load, the PEMFC with horizontal channels exhibits better performance in both the normal gravity environment and the 3.6 s short-term microgravity environment.

An experimental study of mutual effects among two‐phase flow, heat transfer, and performance in proton exchange membrane fuel cells with orientated‐type flow channels

“…Previous publications have utilized the simultaneous testing approaches to investigate the performance and two-phase visualization of PEMFCs, especially in microgravity condition experiments. 22 Guo et al 23 found that the flow field arrangement types affected the water flowing and distributing behaviors of PEMFCs, and the current generation situations affected the level of water generation and flowing. 24 Liu et al 25 conducted simultaneous testing experiments to investigate the synchronous changing of pressure drops, current densities, and the liquid water moving behaviors inside PEMFCs.…”

Droplet Dynamics in a Proton Exchange Membrane Fuel Cell with Ejector-Based Recirculation

“…In recent years, extensive research has been conducted on the dynamic flow characteristics of water in fuel cells. Some researchers have directly characterized methods for monitoring the distribution of liquid water inside the fuel cell, including nuclear magnetic resonance (NMR) imaging, − neutron imaging, , X-ray, , and optical photography. − Although NMR imaging can accurately reflect the internal water content and flow state of the fuel cell under online working conditions, it is almost impossible for NMR imaging to visually characterize the water content in the GDL and the catalytic layer . In comparison to X-ray and neutron imaging technology, optical photography requires a relatively low cost and fuel cell testing methods are relatively simple.…”

“…In comparison to X-ray and neutron imaging technology, optical photography requires a relatively low cost and fuel cell testing methods are relatively simple. Optical photography technology has been extensively used to analyze the transmission of liquid water in transparent PEMFCs. , …”

“…Optical photography technology has been extensively used to analyze the transmission of liquid water in transparent PEMFCs. 27,28 The experimental study of the water transport process in a PEMFC flow channel is limited by multiple operating conditions. For example, modifying the PEMFC and replacing the commonly used opaque carbon bipolar plate with a transparent material in the optical photography method is essential.…”

A numerical study on convection and diffusion of mass transfer in proton exchange membrane fuel cells with orientated‐type flow channels

“…Water and heat managements are key issues, which are related with the reactants transportation into catalyst layers (CLs) and the electrochemical reactions 2 . The gas‐liquid two‐phase flow behavior is impacted by the gravity situations, and previous literature has proved that the liquid water moving processes were various in different flow channel configurations when the gravity situation was changed 3,4 . Moreover, under different operation situations, because of the difference in electrochemical reaction rates, the water production amount was changed, therefore, the gas‐liquid characteristics were reformed 5 .…”