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

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

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

 VALIDATION OF NUMERICAL MODELS/CODES INTRODUCTION 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 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

DATA ACQUISITION SYSTEM GasTeF EXPERIMENTS 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 DATA ACQUISITION SYSTEM

Fast filling of type 4 tanks Experiments Code Validation (ANSYS CFX 12.1) Assess code accuracy of high pressure hydrogen tank fast filling Evaluate internal and external temperature distribution H2 Pin [MPa] H2 Pfin [MPa] tfilling [s] Tsleeve [°C] H2 Tini TCs Test H2 10122010 0.02 71.7 330 16 21 Pos 2 Test H2 25022011 71.8 245 18 Pos1, 2 Vol=29 l Φ 0.28m 0.83m

CFD SIMULATIONS Computational model Fluid Domain Solid Domains 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

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

Temperature distribution CFD SIMULATIONS Results 100 s 330 s 200 s 330 s Temperature distribution

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

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

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

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

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.

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

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/