International Conference on Hydrogen Safety ICHS 2011

1. International Conference on Hydrogen Safety ICHS 2011 September 12-14, 2011 San Francisco, California-USA Validation of Computational Fluid Dynamics Models for Hydrogen Fast Filling Simulations M. C. Galassi, E. Papanikolaou, M. Heitsch, D. Baraldi, B. Acosta Iborra, P. Moretto

2. OUTLINE • Introduction • Motivation • Fast Filling issues • Why CFD • GasTeF Experiments • CFD Simulations • Model • Results • Conclusions Experiments Modeling

3. INTRODUCTION Competitive with current technologies Three main targets: short refueling time  3 min long driving range  35-70 MPa high safety and reliability High temperature can be reached in the tank during refueling. Limit of 85 degrees in ISO/TS 15869, 2009 Limitof 85°C

4. WHY CFD? CFD can provide 3D detailed and complete flow-field information over a wide range of flow configurations Relevant information for hazards and risk assessment of hydrogen technologies (e.g. P and T loads) Valuable contribution to design, optimization, innovative solutions INTRODUCTION High level of reliability and accuracy of the numerical models is required in order to apply CFD to real-scale problems  VALIDATION OF NUMERICAL MODELS/CODES

5. GasTeF EXPERIMENTS DATA ACQUISITION SYSTEM • Gas tanks Testing Facility • EU reference laboratory on safety and performance assessment of high-pressure hydrogen (and natural gas) storage tanks • Fast filling, cyclic and permeation testing

6. Fast filling of type 4 tanks Φ 0.28m 0.83m • Experiments • Code Validation (ANSYS CFX 12.1) • Assess code accuracy of high pressure hydrogen tank fast filling • Evaluate internal and external temperature distribution Vol=29 l

7. CFD SIMULATIONS • Computational model • Fluid Domain • Hydrogen • Solid Domains • Liner (High Density Poly Amide Epoxy) • Insulation (Composite CF) • Bosses (steel) • ~ 560k nodes, 900k cells • Probes at Thermo Couples position Pos2 Pos1

8. CFD SIMULATIONS • Boundary and Initial Conditions (BIC) • Fluid Domain • BCs at inlet:T,p • BCs at walls: Conjugate Heat Transfer, no slip • ICs: Still at T0 • Solid Domains • BC: Conjugate Heat Transfer, Heat Transfer Coefficient (with amb. air) • ICs: Tamb Test H2 10122010 Test H2 25022010

9. CFD SIMULATIONS • Results 100 s 330 s 200 s 330 s Temperature distribution

10. CFD SIMULATIONS • Results Pos2: TC1,2,3,4,5 Test H2 10122010

11. CFD SIMULATIONS • Results Pos2: TCext1, TCext2, TCext3 Test H2 10122010

12. CFD SIMULATIONS • Results Pos1: T2,T4 Test H2 25022010 Pos2: T2, T4

13. CFD SIMULATIONS • Results: Maximum temperatures at the end of the filling procedure Test H2 25022010 Pos1 Pos1 Test H2 10122010

14. CONCLUSIONS (1/2) • CFD validation against experimental data for hydrogen fast filling prediction up to 72 MPa • Two different tests: similar working conditions but different filling time • The developed model proved to accurately predict internal maximum temperature for both tests (maximum error<7%), • Prediction of external maximum temperature was less accurate (maximum error~15%) and strongly dependent on material properties.

15. CONCLUSIONS (2/2) • Further investigation is required on • Material properties • Heat exchange between fluid, tank walls and environment • Different turbulence models • A fully validated CFD model will • Allow reliable predictions of fast filling scenarios • Constitute a valuable complementary tool to experimental campaigns supporting • Design and optimization process • Development of innovative solutions

16. THANK YOU FOR YOUR ATTENTION ! Maria-Cristina.GALASSI@ec.europa.eu daniele.baraldi@jrc.nl http://ie.jrc.ec.europa.eu/ http://www.jrc.ec.europa.eu/