Manifold Design in a PEM Fuel Cell Stack to Improve Flow Distribution Uniformity

Abstract

In this paper, a numerical study was performed to investigate the flow distribution in a 52-cell proton exchange membrane (PEM) fuel cell stack. The non-uniformity factor and standard deviation parameters were used to determine the flow distribution uniformity. Flow channels of each bipolar plate were replaced with straight parallel channels filled with porous media to reduce computational costs. The effect of external and integrated humidifiers on the gas distribution among the channels was investigated. Using integrated humidifiers improved the non-uniformity factor and standard deviation by 35% and 19%, respectively. Two methods were employed to improve the flow distribution: gradual reduction of the manifold height, and installing a bump at the bottom wall of the inlet manifold. Reducing the height of the inlet manifold in the stack with integrated and external humidifiers decreased the non-uniformity factor by 62% and 44%, respectively. The installation of the bump on the manifold wall enhanced flow distribution in the stack with the external humidifier. The results show that by using an integrated humidifier in this method, the flow distribution became more non-uniform. The best flow distribution in the stack was obtained with an integrated humidifier and a 90% reduction in manifold height. In this case, the flow rate passing through each channel was more than 99% of the average mass flow rate passing through the entire channel.

A High Voltage Gain Interleaved DC-DC Converter Integrated Fuel Cell for Power Quality Enhancement of Microgrid

“…The high voltage gain and reduced voltage ripple of the proposed DC-DC converter ensures a reduction of the current ripple of the system that is caused by the non-linear electrical loads. The microgrid must eliminate the lower order harmonics, otherwise it can inject a low frequency AC current to the PEMFC and subsequently cause performance disorder by shifting its polarity region [39]. Thus, due to the implementation of the high voltage gain DC-DC converter, the lower order harmonics are eliminated from the microgrid's current, which can also prevent the PEMFC from operating outside the polarization region.…”

Effect of Manifold and Distributor Dimensions on Flow Characteristics in PEM Fuel Cell Stack

“…Lebeak et al [7], observed jet flow behaviour when the circular geometry changes to rectangular when entering to manifold which causes the flow maldistribution. The more flow distribution in the final 20% of the channels than initial channels due to high velocity [8], reducing channel hydraulic diameter and increasing the manifold dimension [9], reducing channel width and increasing pressure drop [10], providing double inlet and outlet manifold configurations [11] are some of the findings for flow distribution in manifold as well as in flow channel. This work emphasis the effect of manifold and distributor dimension on anode side of a 5-cell stack with serpentine flow field.…”