Cell, Stack and System Modelling 313 zwo. 16l399. 236169. m3a 1Snm. 1574TI. 131246 rn 515519 93.6955 Figure 11.6 (a) Three-dimensional section of a tubulardesign: (b) current density; (c) molarfraction of 02: (d) temperatureat theoutlet section.