rho1 (p_amb+p1)*M_gas/(R_const*T1) Gas density, inlet channels
rho2 (p_amb+p2)*M_gas/(R_const*T2) Gas density, outlet channels
v1 -k_l*p1X Flow velocity, inlet channels
v2 -k_l*p2X Flow velocity, outlet channels
v_m (H/4)*(p1-p2)*a*b/(a+b) Superficial flow velocity through membrane
b 4*kappa_s/(H*ds*eta) Soot-layer transport coefficient