3D Thermomechanical Long Term Behaviour of Solid Oxide ... · Thermofluid Analysis (CFD) ! Thermomechanical Analysis ... Institute of Energy and Climate Research–Electrochemical

Mitg

lied

der H

elm

holtz

-Gem

eins

chaf

t

3D Thermomechanical Long Term Behaviour of Solid Oxide Fuel Cells, Operating in Furnace: A Combined

Multiphysics and Sub-Modelling Approach

Piero Lunghi Conference 2013: Rome, Italy

M. Peksen, A. Al-Masri, L. Blum, D. Stolten Institute of Energy and Climate Research-Electrochemical Process Engineering (IEK-3) Forschungszentrum Jülich GmbH, Germany

Integrated 20kW Fuel Cell System-Jülich

Institute of Energy and Climate Research–Electrochemical Process Engineering (IEK-3)/SOFC Modelling 2

Contents

§  Introduction “Fuel Cell Operation in Furnace„

§  Objectives & Approach

§  Multiphysics Analysis via Sub-modelling §  Thermofluid Analysis (CFD) §  Thermomechanical Analysis (FEM)

§  Concluding remarks

§  Acknowledgement


Contents







Introduction §  Most of the SOFC research is conducted in

furnace operation!

§  Hermeticity problems are still observed!

§  Better understanding of the effect of different operating conditions on TM of stacks in furnace required!

§  Knowledge of detailed thermomechanical long-term behaviour needs to be improved

§  The combination of experiments and modelling may shed light on the issue


Contents







Objectives

§  To investigate the long-term behaviour of SOFC stacks in furnace operation

§  Evaluate the thermomechanical response and long-term

behaviour

§  Investigate the critical manifold regions under different operating parameters

§  Utilise effectively experimental measurements and advanced modelling techniques


Approach

System and furnace model Validation step Sub-model step


Contents







Applied Thermal B.Cs and Resulting CFD Predictions

H2

77% CH4

38% CH4

H2

77% CH4

38% CH4

Thermofluid Analysis


Thermomechanical Analysis

Fuel Side Von Mises Stress Distribution

Air Side Von Mises Stress Distribution

7MPa 12MPa 10MPa

13MPa

77% CH4 H2 38% CH4

14MPa 30MPa


Thermomechanical Analysis

1200h 77% CH4 Operation

3.97 Mpa (III)

Experimental Data* *Chiu YT, Lin CK, Wu JC, High-temperature tensile and creep properties of a ferritic stainless steel for interconnect in solid oxide fuel cell, J Power Sources, 2011;196: 2005-2012.

Deformation propagates by reducing stress => Negative for the joined sealants!

Stack: F''2011-Dummy-29

Sealant

Stack: F''2011-Dummy-25


Contents



§  Multiphysics Analysis via Sub-modelling §  Thermofluid Analsyis (CFD) §  Thermomechanical Analysis (FEM)




Concluding remarks

§  Long-term TM behaviour of fuel cells operating in furnace has been investigated, using advanced modelling techniques

§  A 3D multiphysics sub-model of the Julich F-Design was utilised §  Material and geometrical non-linearities are considered §  All modes of heat transfer, flow are considered §  Experimentally determined non-linear elastic-plastic material behaviour

and time, rate-dependent creep strain are included §  Experimentally determined operating conditions are employed

§  The thermomechanical response of the manifold region subject to different process conditions has been investigated for 100h constant operation

§  Air side shows higher stress values than the fuel side §  77%CH4 operation shows the least stress compared to H2 and 38%CH4 §  1200h 77%CH4 operation predictions show that the creep deformation

expands and reduces stress, which reveals that the sealants at these locations a prone to leakage and failure. A higher creep resistant steel or design optimisation of the manifold region is required.


Contents



§  Multiphysics Analysis via Sub-modelling §  Thermofluid Analsyis (CFD) §  Thermomechanical Analysis (FEM)




Acknowledgment

§  The technical staff of the Forschungszentrum Jülich is gratefully acknowledged for their support.


Thank you for your attention!


Multiphysics modelling- rate dependent long-term B C

System vs. Furnace

Documents

3D Thermomechanical Long Term Behaviour of Solid Oxide ... · Thermofluid Analysis (CFD) ! Thermomechanical Analysis ... Institute of Energy and Climate Research–Electrochemical