Study of Proton Exchange Membrane Fuel Cells (PZT-PEMFCs) With Nozzle and Diffuser

2009 ◽  
Author(s):  
Hsiao-Kang Ma ◽  
Shih-Han Huang ◽  
Ya-Ting Cheng ◽  
Chen-Chiang Yu ◽  
Chrung Guang Hou ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Vibration Frequency ◽  
Proton Exchange Membrane ◽  
Air Flow ◽  
Proton Exchange ◽  
Water Flooding ◽  
Theoretical Studies ◽  
Vibration Frequencies ◽  
Innovative Design ◽  
Exchange Membrane

Previous theoretical studies have shown that piezoelectric proton exchange membrane fuel cells (PZT-PEMFCs) might solve water flooding problems and increase cell performance. The innovative design of PZT-PEMFCs results in more oxygen being compressed into the catalyst layer. This enhances the electrochemical reaction and the current density, especially at a high PZT vibration frequency (64 Hz). In this investigation, a single, valveless PZT-PEMFC experimental fuel cell is built. The results are then compared with those of previous theoretical studies. This study includes an analysis of PZT vibration frequencies, and cell operation temperatures. A Nafion 212 membrane with a reaction area of 2 cm × 2 cm is used to measure the voltage and average current density under different temperatures and vibration frequencies. When the PZT device moves upward and increases the chamber volume, a diffuser directs most of the air to the outlet. In the valveless PZT-PEMFC, both a nozzle and diffuser are used. This innovative design may direct air flow into the cathode channel through the diffuser and prevent air backflow. The nozzle/diffuser design in this study can direct a single directional air flow without valves. The experimental results indicate that the direction in which the cell is mounted have a negligible effect on cell performance due to air flow through the nozzle. The diffuser is not influenced by gravity. The optimal operating temperature for the PZT-PEMFC of this study is 50°C, as higher temperatures dry out the membrane electrode assembly (MEA). The optimal vibration frequency of the PZT-PEMFC is 180Hz, as higher frequencies cause more air intake and solve the problem of water flooding in the cathode channel. This study also concludes that the innovative design of PZT-PEMFCs may equal the performance of an open cathode stack configuration and can be applied in a fuel cell stack without an external air supply device.

Study of a Pseudo Bipolar Design for a Piezoelectric Proton Exchange Membrane Fuel Cell With Nozzle and Diffuser

2010 ◽  
Author(s):  
Hsiao-Kang Ma ◽  
Jyun-Sheng Wang ◽  
Ya-Ting Chang
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Proton Exchange Membrane ◽  
Produced Water ◽  
Three Dimensional ◽  
Proton Exchange ◽  
Cell Performance ◽  
Water Flooding ◽  
Geometrical Parameters ◽  
Exchange Membrane

Previous studies of a piezoelectric proton exchange membrane fuel cell with nozzle and diffuser (PZT-PEMFC-ND) have shown that a PZT device could solve flooding problems and improve cell performance. The results also indicated that the rectification efficiency (γ) of the diffuser elements, the PZT vibrating frequency (f), and the displaced volume per stroke (ΔV) affected the flow rate of the PZT device. The rectification efficiency of the diffuser elements, which is an indicator of the preferential direction, depends on the geometrical parameters (AR and θ) and the Reynolds number. In this study, an innovative design for a PZT-PEMFC-ND bi-cell with pseudo bipolar electrodes was developed to achieve a higher power in the stack design to solve water flooding problems and improve cell performance. This new design, with a reaction area of 8 cm2, contains two cells with two outside anodes and two inside cathodes that share a common PZT vibrating device for pumping air flow. The influence of the varying aspect ratio (AR) of the diffuser elements on the unit cell flow rate were investigated using a three-dimensional transitional model. The results show that a proper AR value of 11.25 for the diffuser with a smaller θ of 5° could ensure a smoother intake of the air and thus better cell performance. A lower AR value of 5.63 resulted in smaller actuation pressure inside the chamber, and thus the produced water could not be pumped out. However, a larger AR of 16.88 induced a blocking phenomenon inside the diffuser element, and thus less air was sucked into the cathode chamber. The performance of the PZT-PEMFC-ND bi-cell could be 1.6 times greater than that of the single cell. This performance may be influenced by the phase difference of the operating modes.

Innovative Design of an Air-Breathing Proton Exchange Membrane Fuel Cell With a Piezoelectric Device

2009 ◽  
Vol 6 (3) ◽  
Author(s):  
Hsiao-Kang Ma ◽  
Shih-Han Huang
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Three Dimensional ◽  
Catalyst Layer ◽  
Proton Exchange ◽  
Innovative Design ◽  
Current Output ◽  
Air Breathing ◽  
Piezoelectric Device ◽  
Exchange Membrane

This paper presents a three-dimensional transitional model to describe an innovative design for an air-breathing proton exchange membrane fuel cell (AB-PEMFC) with a microdiaphragm actuated by a piezoelectric device. This newly designed gas pump with a piezoelectric actuation structure is utilized as an air-flow channel in a proton exchange membrane fuel cell (PEMFC) system called PZT-PEMFC. When the actuator moves in the outward direction to increase the cathode channel volume, the air is sucked into the chamber: inward movement decreases channel volume and thereby compresses air into the catalyst layer and enhances the chemical reaction. The air-standard PZT-PEMFC cycle coupling with fuel∕air ratio is proposed to describe an air-breathing PZT-PEMFC. The model is able to simulate its major phenomena and performance in different fuel∕air ratio and PZT frequency. The results show that the PZT actuation leads to a more stable current output, more drained water, stronger suction, and overcome concentration losses at a proper PZT frequency.

The Effects of Feeding Configurations to Water Flooding and General Performance of a Proton Exchange Membrane Fuel Cell

2005 ◽  
Author(s):  
A. B. Mahmud Hasan ◽  
S. M. Guo ◽  
S. V. Ekkad
Keyword(s):  
Fuel Cell ◽  
Power Density ◽  
Current Density ◽  
Proton Exchange Membrane ◽  
Cell Voltage ◽  
Bipolar Plate ◽  
Proton Exchange ◽  
Water Flooding ◽  
Cathode Side ◽  
Exchange Membrane

The performance of a Proton Exchange Membrane Fuel Cell (PEMFC) using different feeding configurations has been studied. Three bipolar plates, namely serpentine, straight channel and interdigitated designs, were arranged in different combinations for the PEMFC anode and cathode sides. Nine combinations in total were tested under different flow rates, working temperatures and loadings. The cell voltage versus current density and the cell power density versus current density curves were obtained. After operating the PEMFC under high current densities, the cell was split and the water flooding in the feeding channels was visually inspected. Experimental results showed that for different feeding configurations, interdigitated bipolar plate in anode side and serpentine bipolar plate in cathode side had the best performance in terms of cell voltage-current density curve, power density output rate, percentage of flooded area in the feeding channels, the pattern of flooding and the fuel utilization rate.

Effect of Gravity on Droplet Growth and Detachment Inside a Simulated PEM Fuel Cell Air Flow Channel With Hydrophobic Walls

2013 ◽  
Author(s):  
Andres Munoz ◽  
Abhijit Mukherjee
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Air Flow ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Droplet Growth ◽  
Flow Rates ◽  
Air Supply ◽  
Supply Channel ◽  
Exchange Membrane

Water management still remains a challenge for proton exchange membrane fuel cells. Byproduct water formed in the cathode side of the membrane is wicked to the air supply channel through the gas diffusion layer. Water emerges into the air supply channel as droplets, which are then removed by the air stream. When the rate of water production is higher than the rate of water removal, droplets start to accumulate and coalesce with each other forming slugs consequently clogging the channels and causing poor fuel cell performance. It has been shown in previous experiments that rendering the channels hydrophobic or super-hydrophobic cause water droplets to be removed faster, not allowing time to coalesce, and therefore making channels less prone to flooding. In this numerical study we analyze water droplet growth and detachment from a simulated hydrophobic air supply channel inside a proton exchange membrane (PEM) fuel cell. In these numerical simulations the Navier-Stokes equations are solved using the SIMPLER method coupled with the level set technique in order to track the liquid-vapor interface. The effect of the gravity field acting in the −y, −x, and +x directions was examined for an array of water flow rates and air flow rates. Detachment times and diameters were computed. The results showed no significant effect of the gravity field acting in the three different directions as expected since the Bond and Capillary numbers are relatively small. The maximum variations in detachment time and diameter were found to be 8.8 and 4.2 percent, respectively, between the horizontal channel and the vertical channel with gravity acting in the negative x direction, against the air flow. Droplet detachment was more significantly affected by the air and water flow rates.

scholarly journals Energy efficiency improvements by investigating the water flooding management on proton exchange membrane fuel cell (PEMFC)

Energy ◽  
2019 ◽  
Vol 179 ◽  
pp. 246-267 ◽  
Author(s):  
O.S. Ijaodola ◽  
Zaki El- Hassan ◽  
E. Ogungbemi ◽  
F.N. Khatib ◽  
Tabbi Wilberforce ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Water Flooding ◽  
Exchange Membrane

Study of the distribution of air flow in a proton exchange membrane fuel cell stack

2009 ◽  
Vol 192 (1) ◽  
pp. 185-189 ◽  
Author(s):  
Radu Mustata ◽  
Luis Valiño ◽  
Félix Barreras ◽  
María Isabel Gil ◽  
Antonio Lozano
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Air Flow ◽  
Proton Exchange ◽  
Fuel Cell Stack ◽  
Exchange Membrane

Liquid water flooding in a proton exchange membrane fuel cell cathode with an interdigitated design

2011 ◽  
Vol 35 (15) ◽  
pp. 1292-1311 ◽  
Author(s):  
Simo Kang ◽  
Biao Zhou ◽  
Chin-Hsiang Cheng ◽  
Huan-Ruei Shiu ◽  
Chun-I Lee
Keyword(s):  
Fuel Cell ◽  
Liquid Water ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Water Flooding ◽  
Fuel Cell Cathode ◽  
Exchange Membrane ◽  
Cell Cathode

Numerical Modeling of Proton Exchange Membrane Fuel Cell With Considering Thermal and Relative Humidity Effects on the Cell Performance

2006 ◽  
Vol 3 (3) ◽  
pp. 292-302 ◽  
Author(s):  
Pei-Hung Chi ◽  
Fang-Bor Weng ◽  
Ay Su ◽  
Shih-Hung Chan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fuel Cell ◽  
Relative Humidity ◽  
Proton Exchange Membrane ◽  
Thermal Field ◽  
Proton Exchange ◽  
Cell Performance ◽  
Water Flooding ◽  
Exchange Membrane

A three-dimensional (3D) model has been developed to simulate proton exchange membrane fuel cells. The model accounts simultaneously for electrochemical kinetics, current distribution, hydrodynamics, and multi-components transport. A single set of conservation equations of mass, momentum, energy, species, and electric current are developed and numerically solved using a finite-volume-based computational fluid dynamics technique (by computational fluid dynamics ACE+ commercial code). The physical model is presented for a 5cm×4.92cm×0.4479cm 3D geometry test cell with serpentine channels and counter flow. Subsequently, the model is applied to explore cell temperature effects in the cell environment with different relative humidity of inlet. The numerical model is validated and agreed well with the experimental data. The nonuniformity of thermal and water-saturation distributions is calculated and analyzed as well as its influence on the cell performance. As the cell is operated at low voltages (or high current densities), the thermal field of fuel cell tends to be nonuniform and exists locally in hot spots. The mechanism of thermal field and water content interacted with membrane dehydration and cathode water flooding will be discussed and revealed their influences on the cell performance, stability and degradation will be revealed.

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