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MODELING THERMAL RESPONSE OF POLYMER COMPOSITE HYDROGEN CYLINDERS SUBJECTED TO FIRE

This study focuses on developing a thermo-mechanical model to predict the response of polymer composite hydrogen cylinders subjected to fire. The aim is to enhance fire resistance by understanding decomposition and degradation mechanisms. Utilizing CFD and FE models, heat transfer, decomposition, and degradation are simulated to aid in designing cylinders with prolonged fire resistance. Experimentally obtained properties are incorporated to investigate cylinder behavior under thermal and pressure loads, aiming for enhanced safety in hydrogen energy applications.

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MODELING THERMAL RESPONSE OF POLYMER COMPOSITE HYDROGEN CYLINDERS SUBJECTED TO FIRE

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  1. MODELING THERMAL RESPONSE OF POLYMER COMPOSITE HYDROGEN CYLINDERS SUBJECTED TO FIRE Zaki S. Saldi, Jennifer X. Wen Warwick FIRE, School of Engineering University of Warwick The International Conference on Hydrogen Safety Yokohama, 19-21 October 2015

  2. Background California Fuel Cell Partnership cafcp.org http://www.toyota.com/mirai/fcv.html • Zero carbon emission from transportation  hydrogen energy  HFCV. • Low volumetric energy density H2 (5.6 MJ/L)  compressed storage, carbon fibre reinforced composite (CFRP) tank, 35-70 MPa. • Type-3 (aluminum liner), type-4 (HDPE plastic liner). • Slow venting of H2 through TPRD required in the event of accident with fire (GB: 23100 road vehicle fires in 2013-2014). • Fire resistance: 3.5-6.5 minutes (type 4) (Weyandt, 2006), 12 minutes (type 3) (Zalosh& Weyandt, 2005), too short.

  3. Background Brennan & Molkov(2011): Venting within 3 min requires TPRD diameter of 5 mm. At 35 MPa, the corresponding flow rate is about 390 g/s (overpressure 10-20 kPa, garage destroyed in less than 2 s) In an open space, 70 MPa & 5 mm: “no harm” separation distance from the car is about 50 m. Need for enhanced fire resistance ( > 1 hour)

  4. Objectives To develop a thermo-mechanical model with decomposition & degradation mechanism for calculating the response of composite cylinder under thermal and pressure loadings. To use experimentally obtained physical-chemical properties in the model. To use the model for chosen fire testing scenarios & to aid in the design of cylinders with enhanced fire resistance.

  5. Outline Background & objectives Numerical models CFD model for external fire FE model for cylinder structure Results H2cylinder subjected to propane fire (burst testing) Summary

  6. Numerical models CFD Heat Flux FE Mouritz et al (2009) • Computational Fluid Dynamics for fire. • Finite Element simulation for cylinder thermo-mechanics (heat transfer, decomposition, degradation). • One-way coupling through heat flux from fire (CFD) to cylinder (FE).

  7. CFD model for external fire Combustion: extended Eddy Dissipation Concept. Finite Volume, Large Eddy Simulation, FireFOAM (OpenFOAM). Wang, C.J. , Wen, J.X. and Chen, Z.B. 'Simulation of Large-Scale LNG Pool Fires Using FireFOAM' Combustion Science and Technology, 2014 Wang, C.J. , Wen, J.X. and Chen, Z.B. , Dembele, S. 'Predicting radiative characteristics of hydrogen and hydrogen/methane jet fires using FireFOAM' International Journal of Hydrogen Energy, 2014

  8. CFD model for external fire • Extended EDC model: • Original version: Magnussen (1989) • Currently used: modification of total turbulent kinetic energy & dissipation rates to include subgrid scale quantities to accommodate LES (Chen, 2011). CD1 = 0.135, CD2 = 0.5, kSGS: one-equation linear eddy model (Menon, 1996) Fine structures assumed as stationary homogeneous perfectly stirred reactor. Reaction rates depend on: mass transfer rates with surrounding fluids, mass fraction of the fine structures, reacting fraction.

  9. FE model for H2 cylinder • Energy equation • Source terms - Gas convection: - Time rate of change due to decomposition: - Enthalpies of composite & gas: • Decomposition model based on: Henderson, J., Wiecek, T., “A Mathematical Model to Predict the Thermal Response of Decomposing, Expanding Polymer Composites”, Journal of Composite Materials, Vol. 4, pp 373-393, 1987. • Implemented in Elmer, open source FE code.

  10. FE model for H2 cylinder • A Model for the Thermal Response of Polymer Composite Materials with Experimental Verification, J.B. Henderson, J.A. Wiebelt and M.R. Tant, Journal of Composite Materials 1985, 19: 579

  11. Results Problem under investigation: H2 cylinder in propane fire  Fire exposure burst test, Zalosh & Weyandt (2005). • Mesh sensitivity analysis • Effects of radiation sub-model • Effects of heat transfer coefficient at cylinder wall • Decomposition of CFRP cylinder • Initial estimate of cylinder fire resistance.

  12. H2 cylinder, propane fire Experiment: ZaloshR., and Weyandt N., Hydrogen Fuel Tank Fire Exposure Burst Test, SAE paper number 2005-01-1886, 2005. • Type-4 composite cylinder • Initial pressure 34.3 MPa. • Propane flowrate 415-580 scfh. • HRR ~ 370 kW (95% burning eff). • Rupture time 6 min 27 s, internal pressure at rupture = 357 bar.

  13. H2 cylinder, propane fire • Hexahedral, unstructured mesh • snappyHexMeshOpenFOAM tool • Three meshes for mesh sensitivity study: • ~0.7M, ~1.7M, ~3.4M

  14. H2 cylinder, mesh sensitivity

  15. Radiation sub-model • Radiation is modeled by solving the radiative heat transfer equation using fvDOM. • Two sub-models for absorption & emission properties of water vapour and carbon dioxide: • Grey mean absorption coefficient. • Weighted sum of grey gas.

  16. Heat transfer coefficient • Heat flux at cylinder wall: (*) Overall coefficient that combines convective and radiative heat transfer, used in further analysis.

  17. H2 cylinder, propane fire

  18. H2 cylinderdecomposition Around 50% of CFRP decomposed after 600 s

  19. H2 cylinder fire resistance Hu et al, IJHS, 2008 • Fire resistance (initial estimate) based on internal pressure (function of temperature). (Deming WE, Shupe LE. Some physical properties of compressed gases, III. Hydrogen. Phys Rev 1932;40:848–59  covering -2150C < T < 5000C and p up to 1200 atm). • Internal pressure at failure time in experiment (Zalosh, 2005): 357 bar. • Predicted fire resistance: 399 s (6 mins 39 s), Zalosh experiment: 6 mins 27 s.

  20. Summary • LES simulation of fire using FireFOAM. • One way coupling between CFD (fire) & FE (cylinder) through mean heat flux predicted by CFD. • Around 50% of tank CFRP decomposed after 600 s. • Type-4 cylinder in propane fire (hydrogen tank fire exposure burst test, Zalosh & Weyandt, 2005): Fire resistance based on initial prediction using internal pressure (6 min 39s) closely matches experimental value (6 min 27s). • More validation needed (e.g. heat flux). • Ongoing works on thermo-mechanical FE model implementation in Elmer to predict stress distribution, structure failure index using progressive failure criteria.

  21. Acknowledgements • EPSRC Ref EP/K021109/1 • Dr D. Makarov, Prof. V. Molkov (University of Ulster) & Dr T. Mays (University of Bath). • Advisory board. ご清聴ありがとうございます

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