Distribution of SOFC thermal stress via helium gas (He) based cooling system

Abstract

Some electrochemical devices, such as fuel cells, transforms chemical energy to electricity. The main issue of SOFC's is the thermal stress caused by high operating temperature (700–1000°C). Thermal stress leads to crack initiation and propagation that in turn leads to gas leakage, structure instability and abrupt termination of the fuel cell (estimated in our previous work; 1.5% displacement of cathode electrode and the lifetime decreases by 40%–50%). The purpose of the current study is to show the influence of helium gas cooling system on SOFC cell performance. Using the coupled governing nonlinear differential equations, heat transfer, fluid flow, mass transfer, mass continuity, tortuosity effects and momentum. An in‐house computer code based on finite element method (FEM), computational structural mechanics, and the computational fluid dynamics (CFD) was utilized. The temperature and stress distribution are calculated using the Navier–Stokes thermo‐fluid, Darcy and energy models. The Results demonstrate that there is a high thermal stress and displacement in the absence of He gas cooling system, but in the case of He cooling system, thermal stress is much less and no displacement is noticed, which leads to an increase of the fuel cell's lifetime up to 35%–40%.