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Investigation of Water Transport Dynamics in Polymer Electrolyte Membrane Fuel Cells Based on a Gas Diffusion Media Layers

Year: 2020 Volume: 14 Issue: 3 86 - 90 Pages

• Authors:
• Saad S. Alrwashdeh
• Henning Markötter
• Handri Ammari
• Jan Haußmann
• Tobias Arlt
• Joachim Scholta
• Ingo Manke

Abstract: In this investigation, synchrotron X-ray imaging is used to study water transport inside polymer electrolyte membrane fuel cells. Two measurement techniques are used, namely in-situ radiography and quasi-in-situ tomography combining together in order to reveal the relationship between the structures of the microporous layers (MPLs) and the gas diffusion layers (GDLs), the operation temperature and the water flow. The developed cell is equipped with a thick GDL and a high back pressure MPL. It is found that these modifications strongly influence the overall water transport in the whole adjacent GDM.

• Keywords:
• Polymer electrolyte membrane fuel cell
• microporous layer
• water transport
• radiography
• tomography.

Laboratory Analysis of Stormwater Runoff Hydraulic and Pollutant Removal Performance of Pervious Concrete Based on Seashell By-Products

Year: 2017 Volume: 11 Issue: 8 1059 - 1068 Pages

• Authors:
• Jean-Jacques Randrianarimanana
• Nassim Sebaibi
• Mohamed Boutouil

Abstract: In order to solve problems associated with stormwater runoff in urban areas and their effects on natural and artificial water bodies, the integration of new technical solutions to the rainwater drainage becomes even more essential. Permeable pavement systems are one of the most widely used techniques. This paper presents a laboratory analysis of stormwater runoff hydraulic and pollutant removal performance of permeable pavement system using pervious pavements based on seashell products. The laboratory prototype is a square column of 25 cm of side and consists of the surface in pervious concrete, a bedding of 3 cm in height, a geotextile and a subbase layer of 50 cm in height. A series of constant simulated rain events using semi-synthetic runoff which varied in intensity and duration were carried out. The initial vertical saturated hydraulic conductivity of the entire pervious pavement system was 0.25 cm/s (148 L/m2/min). The hydraulic functioning was influenced by both the inlet flow rate value and the test duration. The total water losses including evaporation ranged between 9% to 20% for all hydraulic experiments. The temporal and vertical variability of the pollutant removal efficiency (PRE) of the system were studied for total suspended solids (TSS). The results showed that the PRE along the vertical profile was influenced by the size of the suspended solids, and the pervious paver has the highest capacity to trap pollutant than the other porous layers of the permeable pavement system after the geotextile. The TSS removal efficiency was about 80% for the entire system. The first-flush effect of TSS was observed, but it appeared only at the beginning (2 to 6 min) of the experiments. It has been shown that the PPS can capture first-flush. The project in which this study is integrated aims to contribute to both the valorization of shellfish waste and the sustainable management of rainwater.

• Keywords:
• Hydraulic
• pervious concrete
• pollutant removal efficiency
• seashell by-products
• stormwater runoff.

A Study of Thermal Convection in Two Porous Layers Governed by Brinkman's Model in Upper Layer and Darcy's Model in Lower Layer

Year: 2013 Volume: 7 Issue: 3 372 - 378 Pages

• Authors:
• M. S. Al-Qurashi

Abstract: This work examines thermal convection in two porous layers. Flow in the upper layer is governed by Brinkman-s equations model and in the lower layer is governed by Darcy-s model. Legendre polynomials are used to obtain numerical solution when the lower layer is heated from below.

• Keywords:
• Brinkman's law
• Darcy's law
• porous layers
• Legendre polynomials
• the Oberbeck-Boussineq approximation.