燃料电池双极板流道参数的设计：以田口方法和es－pemfc联合优化直流道为例［设计因素其五］

Parametric study ofthe channel design at the bipolar plate in PEMFC performances

SunghoLee

HeeseokJeong

ByungkiAhn

TaewonLim

YoungjinSon

a b s t r a c t

Polymer Electrolyte Membrane Fuel Cell（PEMFC） system consists of many parts and the bipolar plate is one of the keycomponents among them． Channels at the bipolar plate distribute air on thecathode side and hydrogen on the anode side， which are essential for theelectric－chemical reaction to produce electricity． Bipolar plates may also beused as a path for the cooling water to control the temperature of the cell． Thereare several design parameters affecting the performance of the fuel cellsystem， and in this paper， the effects of geometric parameters are consideredwhile others are fixed． It also discusses on how those design parametersaffect the performance of the unit cell with the simple straight channelconfiguration． The parametric study has been conducted using commercialComputational Fluid Dynamics （CFD） techniques， and the results give designersthe ideas on which combination between geometric design parameters would be optimalto get the best performance．

Fig． 1 – Schematic diagram of the simplestraight channel model．

Table 1 – Design parameters for L18 testmatrix

在矩阵中ABC是比例而不是实际值。

Table 2 – Taguchi L18 test matrix

Taguchi L18 test matrix is useful to findthe optimal combination among parameters with different level．

Fig． 2 – Models in different offset ratiosbetween the cathode and the anode channel．

Table 3 – Electrochemical properties andthe dimensions of the geometry

Fig． 3 – V–I curve comparison between experimentaldata and CFD calculation at Case ＃1．

这里只验证了性能，没有验证流体阻力。

Fig． 4 – Current density for differentgeometric configurations for 1．2 A cmL2， type 1， 2， 3 represent the offsetgeometry between cathode and anode channels of （a）， （b）， （c） in Fig． 2，respectively．

Fig． 5 – Current density distribution alongthe channel length， co－flow configuration， case ＃2．

In this study， es－pemfc commercial programis employed for calculations using a simple， straight channel without cooling channels

电流密度的分布状态差异很大。

Fig． 6 – The liquid water mass fraction onthe anode and the cathode side at different current density， co－flow configuration，case ＃2．

在流道末端液态水的质量分数低电流密度阴极多，高电流密度阳极多。

Fig． 7 – The comparison of V–I curvesbetween 1， 2， 3 cases results．

Table 4 – Optimum parameters obtained byTaguchi L18 matrix

OPT中只有B、D、E、F算最优，因为其它的参数不是用了最大就是用了最小。

Fig． 8 – Power and pressure drop curve； at1．2 A／cm2 condition．

应该对于OPT做实验证明一下误差，完成闭环。

但是，功率85kW和84kW差别不是很大，空气流道压力降300Pa和200Pa，氢气流道压力降450Pa和50Pa有很大差别么？

design parameter D may be chosen as level 2of 1：1．5 for the best performance based on this analysis， and the GDL thicknessneeds to be moderate， not too thick nor too thin．

Conclusion

The effects of the design parameters on thePEMFC performance have been examined using CFD calculation． The local currentdensity， concentration and pressure of the reacting

gases， cell temperature， and waterdistribution are obtained by CFD calculation using electrochemical variablesfitted by V–I curve from the real system． There are optimal combination betweenthe design parameters through the trade－off between the performance and thepressure drop in the system design．

The following conclusions can be drawn fromthe CFD calculation in this study：

1） Taguchi method can be useful to get theoptimal combination between design parameters in the system design； however，these parameters are severely coupled．

2） The geometric design parameters in thebipolar plate mainly contribute to increasing the performance of the system byaffecting the concentration loss as expected．

3） The design parameters should be selectedconsidering the effects on the performance and the pressure drop in the channelat the same time to meet the purpose of the PEMFC system．