In addition to the molecular diffusion and electro-osmotic drag, water is generated in the cathode catalyst layer due 17-AAG mechanism to electrochemical reaction.1) Electro-osmotic drag fluxElectro-osmotic water flux through the membrane make it clear can be calculated from the proton flux through the membrane, given by the specified current density and Faraday lawJH2O=2��ndI(x,y)2F:Electro?osmotic drag flux(7)where nd is Electro-osmotic drag coefficient which depends Inhibitors,Modulators,Libraries on water activity as follows.nd=0.0029��2+0.05��?3.4��10?19(8)where �� represents water contend of the membrane described as,��=0.043+17.81aK?39.85aK2+36.0aK3,0

log10Psat=?2.1794+0.02953T?9.1837��10?5T2+1.4454��10?7T3(11)2) Back Inhibitors,Modulators,Libraries diffusion fluxThe water formation at the cathode Inhibitors,Modulators,Libraries results in a gradient in the water content between the cathode side and anode side of the membrane. For PEMFC, this gradient causes a water flux back to anode side which Inhibitors,Modulators,Libraries is superimposed to the electro-osmotic Inhibitors,Modulators,Libraries flux. This back diffusion is expressed as following water flux,JH2O,back diffusion=?��m,dryMm,dry��Dw��d��dz:Back diffusion flux(12)where ��m,dry is the dry density of electrolyte, Mm,dry is the electrolyte equivalent weight, and z is the direction through the membrane thickness.

Dw is water diffusion coefficient Inhibitors,Modulators,Libraries which is strongly1 dependent on water, content as follows,Dw=D��exp(2416(1303?1Tcell));D��=10?10,��<2D��=10?10(1+2(��?2)),2�ܦˡ�3;D��=10?10(3?1.

67(��?3)),3<��<4.5;D��=1.25��10?10,�ˡ�4.5(13)3) Current density and membrane ion ConductivityI(x,y,z) is current density generated by electrochemical reaction, which can be expressed,I(x,y,z)=��m(x,y,z)tmVoc?Vcell?��(x,y,z)(14)where ��m(x,y,z) indicates the ion conductivity of membrane expressed Carfilzomib as,��m(x,y,z)=(0.00514Mm,dry��m,dryCw,a(x,y,z)?0.00326)exp(1268(1303?1Tz))��102(15)2.4. Numerical algorithmThe numerical simulation model is based on SIMPLE (semi-implicit method for pressure linked equations consistent) algorithm using Segregated solver of Fluent? (version 6.3). Uniform flow velocity and reactant concentration at the inlet are given as the initial condition.

Source terms generated by the electrochemical reaction are inserted into mass and species conservation Inhibitors,Modulators,Libraries equation using the User Define Function (UDF).

The coupled set of equations was solved iteratively Dacomitinib until the relative error in each field reached a specific convergent standard (usually 10?9). The flow diagram for this numerical algorithm is represented in Figure 2.Figure 2.A flow diagram of the solution procedure.2.5. Numerical selleckbio simulation modelThe schematics of Volasertib the parallel micro flow channel with GDL and catalyst layer is shown in Figure 3. The cross sectional area at inlet of flow channel is 762��762(��m) and its length is 40(mm).