Transient simulation of failures during start‐up and power cut of a solid oxide fuel cell system using multiphysics modeling

Abstract

We investigate failure incidents of a solid oxide fuel cell (SOFC) system during start-up from ambient conditions as well as during operation around the design point, using numerical simulation with a view to performance and thermo-mechanical stresses. During start-up, which comprises heating and load ramping phases, the system's trajectory moves through a relatively large temperature range. The simulated failure scenarios include reversible operational discontinuities in terms of input parameters and irreversible hardware failures. Furthermore, we also present results for a complete power cut. A multiphysics modeling approach is used to couple thermal, electrochemical, chemical, and thermo-mechanical phenomena by means of time-dependent partial differential, algebraic, and integral equations. Simulations revealed that the system can smooth out thermal discontinuities that are within a few minutes, that is, within the range of its thermal inertia. However, during the initial phase of the start-up procedure, thermo-mechanical stresses are relatively high due to larger differences between the sintering (manufacturing) and operation temperature, which makes the system more susceptible to failure. This work demonstrates that a multiphysics approach with control-and reliability-relevant aspects leads to a realistic problem formulation and analysis for practical applications.

High Temperature Solid Oxide Electrolysis – Technology and Modeling

“…To achieve this, only mass and heat transport are resolved in a time-dependent way and a quasi-stationary state for electrochemistry is assumed. Further the response to temperature changes in startup operation [251][252][253] and for changing operation points [51] are investigated. [51,254] also examines the influence of an operating voltage varying in time while [255] studies the time-dependent distribution of the chemical potential of oxygen through the cell.…”

“…Further the response to temperature changes in startup operation 251–253 and for changing operation points 51 are investigated. 51, 254 also examines the influence of an operating voltage varying in time while 255 studies the time‐dependent distribution of the chemical potential of oxygen through the cell.…”