“…The equations are written in indicial-tensor notation with: ρ, density kg/m 3 ; t, time s; µ dynamic viscosity of oxygen = 2 × 10 −5 Pa-s (5); u, velocity vector m/s; p, pressure Pa; ω i weight fraction of the i th species; with an inlet mass fraction O 2 = 0.1447, a mass fraction of H 2 O = 0.3789, and a mass fraction of N 2 = 0.4764; D e f f ,ij , the effective binary diffusion coefficient (see Equation (4) in [22][23][24]); M, the total molar mass of the mixture g/mol (see Equation (5) in [19][20][21][25][26][27]); M j , the molecular weight of species j, g/mol; MO 2 , the molecular weight of O 2 = 32 g/mol; M H2O , the molecular weight of H 2 O = 18 g/mol; M N2 , the molecular weight of N 2 = 28 g/mol; D ij , the binary diffusion coefficient for species i and j; k, the Maxwell diffusion constant = 3.16 × 10 −8 Pa·m 2 /s; T, temperature = 353 • K; ν i , the molar diffusion volume of the j th species, cm 3 /mol; ν O2 , the molar diffusion volume of O 2 = 16.6 × 10 −6 cm 3 /mol; νH 2 O, molar diffusion volume of H 2 O = 12.7 × 10 −6 cm 3 /mol; νN 2 , the molar diffusion volume of N 2 = 17.9 × 10 −6 cm 3 /mol; for M j , MO 2 , MH 2 O, and MN 2 , see Table 1; ε, porosity = 0.5; i c , cathode current; S a specific surface area = 1 × 10 7 m 2 /m 3 ; δ, active layer thickness = 10 um; i 0 , exchange current density = 1.06 × 10 −6 mA/cm 2 ; F, Faraday's constant = 96485 C/mol, R, gas constant = 8.314 J/(mol·K); η overpotential between 0.2 and 0.82 V; t H 2 O electro-osmotic drag = 3; gdl, gas diffusion layer thickness = 0.2 mm.…”