cfd based modelling approaches for hydrogen safety … · cfd based modelling approaches for...
TRANSCRIPT
CFD based modelling approaches
for hydrogen safety issues
Jennifer Wen
Warwick FIRE, School of Engineering
FIRE http://www.warwick.ac.uk/warwickfire
Outline
• Spontaneous ignition
• Hydrogen jet fires
• Hydrogen deflagration, DDT and
detonation
Centre for Fire and Explosion Studies
Safety relevant properties of
hydrogen/ methane/propane/gasoline vapour
density buoyancy
Heat of combustion Laminar burning
velocity
Flammability range Minimum Ignition energy
Diffusion coefficient
Detonation sensitivity
FIRE http://www.warwick.ac.uk/warwickfire
FIRE http://www.warwick.ac.uk/warwickfire
Spontaneous ignition
FIRE
Spontaneous ignition: two types
of release scenarios
Direct release into air Release through a section
of tube
FIRE http://www.warwick.ac.uk/warwickfire
Own modified version of KIVA-3V
2-D Unsteady Compressible Navier-Stokes equations solved with an Implicit Large eddy simulation (ILES) method
Arbitrary Lagrangian Eulerian (ALE) numerical scheme: convective term solved separately from diffusion terms;
In Lagrangian stage, 2nd-order Crank-Nicolson scheme + 2nd-order central differencing for diffusion and pressure related terms;
In Eulerian phase, 3rd-order Runge-Kutta method + 5th-order upwind weighted essentially non-oscillatory (WENO) scheme for convection terms;
Detailed chemical-kinetic scheme - 8 reactive species and 21 elementary steps –third body and “fall off” behavior considered (Williams 2006);
Multi-component diffusion approach for mixing - thermal diffusion;
Iris model mimics the rupture process
Spontaneous ignition
Validation - Comparison of 1-D release case with
theoretical results based on 1-D shock wave theory
10-micron gird size and a 5th-order WENO scheme
FIRE http://www.warwick.ac.uk/warwickfire
Release through a tube D=3mm, L=6cm)
Release tubes with varied cross-sections – all
with 50 bar pressure
(a) Local contraction
(b) Local enlargement
(c) Abrupt contraction
(d) Abrupt enlargement
FIRE http://www.warwick.ac.uk/warwickfire
Hydrogen Jet Fires
FIRE http://www.warwick.ac.uk/warwickfire
Hydrogen Jet Fires - Two Modelling Approaches
• Pseudo-source approach
(Ewan and Modie 1985)
– Leak modelled from downstream as a sonic jet
with the same mass flow
rate
• Two-domain approach
Numerically solving the
under-expanded shock structure
• Results used as inflow for
the subsequent large eddy simulation of the jet
0 .5( 0 .5 3 6 )
o
e q j D
a
PD D C
P
/ 12( )
1e o
P P
/ 12( )
1e o
1 / 2 1 / 24 .9 9( )
gs
o D
a
DY C
z
Comparison of the predicted mean
temperatures by the two- approaches
Hydrogen jet flame test
Sandia Laboratory
0
1
2
3
4
5
6
1 0 .5 0
the two-domain approaches
the Pseudo source approach
FIRE http://www.warwick.ac.uk/warwickfire
Hydrogen jet fires
• FireFOAM code with own modified EDC - Zhibin Chen, Jennifer Wen, Baopeng Xu, Siaka Dembele, Large eddy simulation of a medium-scale methanol pool fire using the
extended eddy dissipation concept, International Journal of Heat and Mass Transfer, Volume 70, March 2014, Pages 389-408.
- Zhibin Chen, Jennifer Wen, Baopeng Xu, Siaka Dembele, Extension of the eddy dissipation concept and smoke point soot model to the
LES frame for fire simulations, Fire Safety Journal, Volume 64, February 2014, Pages 12-26.
• Finite volume discrete ordinates model (fvDOM)
• Weighted sum of grey gas model for radiation
FIRE http://www.warwick.ac.uk/warwickfire
Nozzle Diameter: 5.08mm
Pressure: 104.8atm
Tank temperature:231.4K
Schefer, R.W., Houf, W.G., Williams, T.C., Bourne B. and Colton, J., Characterization of High-pressure, Underexpanded Hydrogen-jet Flames,
International Journal of Hydrogen Energy, 32, 2007, pp. 2081-2093.
The under-expanded hydrogen jet fire of Schefer et al.
FIRE http://www.warwick.ac.uk/warwickfire 15
The under-expanded hydrogen jet fire of Ekoto et al. Ekoto, I.W., Houf, W.G., Ruggles A.J., Creitz, L.W. and Li, J.X., Large-scale Hydrogen Jet Flame Radiant Fraction
Measurements and Modelling, Proceedings of the 2012 9 th the International Pipeline Conference, Calgary, Alberta,
Canada, 2012, Paper IPC2012-90535, 2012.
FIRE http://www.warwick.ac.uk/warwickfire
Hydrogen explosions
• Deflagration: the combustion or reaction
wave propagates at a velocity less than the
speed of sound.
• Deflagration to detonation transition (DDT)
refers to a phenomenon in ignitable mixtures of
a flammable gas and air (or oxygen) when a sudden transition takes place from a
deflagration type of combustion to a detonation
type of combustion.
• Detonation: the combustion or reaction wave
propagates at a velocity faster than the speed
of sound.
FIRE http://www.warwick.ac.uk/warwickfire
CFD modelling of hydrogen deflagration T. Tanaka, T. Azuma, J.A. Evans, P.M. Cronin, D.M. Johnson, R.P. Cleaver, Experimental study on hydrogen explosions in a full-scale
hydrogen filling station model, Int J of Hydrogen Energy, 32(13), 2007.
Osaka Gas’ Hydrogen
station
Chamber structure for
explosion experiments
3.0
2.0
1.0
0
FIRE http://www.warwick.ac.uk/warwickfire
CFD modelling of hydrogen deflagration
induced by ignited jet release
Shirvill, L.C., Royle, M. and Roberts, T.A., Hydrogen release ignited in a simulated vehicle refuelling
environment, Proc. 2nd Int Conf on Hydrogen Safety, Sep. 11-13, 2007, San Sebastian, Spain.
FIRE http://www.warwick.ac.uk/warwickfire
• Own modified version of OpenFOAM
• Williams’ [13] 21-step hydrogen autoignition mechanism
• Single step reaction was taken from Gamezo et al.
• A single step chemistry derived by ourselves
Hydrogen deflagration, DDT and detonation
FIRE
Hydrogen deflagration, DDT and detonation –
Validation of the single step chemistry
1D steady ZND wave Free-propagating laminar flame
FIRE http://www.warwick.ac.uk/warwickfire
DDT A. Teodorczyk, P. Drobniak, A. Dabkowski, “Fast turbulent deflagration and DDT of hydrogen–air mixtures in small obstructed
channel”, International Journal of Hydrogen Energy, Volume 34, Issue 14, July 2009, Pages 5887-5893
Distance to left end 475mm 595mm
Peak
Pressure
Meas. 3.6MPa 6MPa
Pred. 3.75MPa 5.81MPa
Discrepancy 4.2% 3.2%
Ignition
DDT
FIRE
Measured Predicted
DDT - Validation
• 80 mm×2000 mm tube, L=160 mm, BR = 0.5
• Smallest grid size : 20 micron, structured (AMR)
• Boundary conditions : no-slip reflecting boundaries.
• Fuel: stoichiometric Hydrogen-air mixture
• Ignition: a region of high temperature (2000 K)
FIRE
Detonation propagation in a bifurcated tube
C. J. WANG, S. L. XU AND C. M.
GUO, “Study on gaseous detonation
propagation in a bifurcated tube”,
Journal of Fluid Mechanics (2008),
599: 81-110
FIRE http://www.warwick.ac.uk/warwickfire
Summary of modelling approaches presented
• A dedicated code for spontaneous ignition modified from
Kiva-3V
• A modified FireFOAM code for hydrogen jet fires
• A modified OpenFOAM with newly developed single step
hydrogen reaction cover the full range from laminar to
flames, turbulent deflagration, DDT and detonation
FIRE http://www.warwick.ac.uk/warwickfire
• Sponsors European Commission
The Engineering and Physical Science
Research Council, UK (EPSRC)
FM Global
The National Natural Science Foundation of
China
• Collaborators The Heath and Safety Laboratory
BP
University of Ulster
Warsaw University of Technology
University of Science and technology, China
• Researchers Baopeng Xu
Sergio Ferraris
Changjian Wang
Zhibin Chen
Vendra Madhav Rao
EL Hima
Jianping Zhang
Ali Heidari
• Former colleagues Vincent Tam
Siaka Dembele
Siva Muppala
Acknowledgement