Centre for Fire and Explosion Studies School of Mechanical and Automotive Engineering Kingston University London Centre for Fire and Explosion Studies A Heidari and JX Wen Detonation ID: 721470
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Slide1
Numerical simulation of detonation failure and re-initiation in bifurcated tubes
Centre for Fire and Explosion StudiesSchool of Mechanical and Automotive Engineering, Kingston University London
Centre for Fire and Explosion Studies
A.
Heidari
and J.X.
WenSlide2
Detonation
propagation in bifurcated tubesSlide3
Outline
IntroductionDeflagration, Detonation and DDT
Equations, Reaction and Modelling approach
Code development and testing
Detonation
simulation
Summery Slide4
Combustion waves
Detonations
DDT
Laminar
flames
Turbulent
flames
3 m/s
800 m/s
2000 m/s
low speed
High speed
Deflagrations
Detonations
U
0.1
atm
5
atm
20
atm
P
Diffusion of mass and energy
Auto-ignition due to shock heatingSlide5
Multidimensional, time-dependent, compressible reactive
Navier–Stokes equations Modelled:
chemical reactions
molecular diffusion
thermal conduction
viscosity
Governing equations & Numerical modelling
Slide6
Turbulence & Numerical modelling
Discretization: Gaussian finite volume integration
Time derivatives: Crank-Nicholson
Van Leer (TVD) scheme for shock capturing
Monotone Integrated Large Eddy
Simulation (MILES)
“monotone
schemes have an inherent truncation error that acts as a numerical diffusion, which can emulate the effects of physical
viscosity”Slide7
Grid independency testSlide8
Testing the solver for Detonation and Deflagration wavesSlide9
Structure of detonation frontSlide10
Boundary and initial conditions
Smallest grid size: 10 micron, structured (AMR)20 grid points across the detonation half reaction length Boundary conditions: no-slip reflecting boundaries
Fuel:
Hydrogen-Oxygen-diluent
mixture
Ignition: a region of high temperature and pressure (T= 2500 K, p= 15
atm
)
Single step reactions, 16
kPa
, 300 K initialSlide11
Detonation propagation in a bifurcated tubeSlide12
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: 81-110Slide13
Detonation failure due to shock diffraction Slide14
Detonation re-initiationSlide15
Detonation propagation in a bifurcated sectionSlide16
Summery
A solver for simulation deflagration, flame acceleration and detonation is developed and validated. Monotone Integrated Large Eddy Simulation (MILES
) is used
Structured mesh and Adaptive Mesh Refinement is used to increase the efficiency and reduce the computational cost.
Good agreement with experiments and other numerical works is achieved.
Detonation failure due to wave diffraction and subsequent detonation re-initiation is simulated and compared against the experimental observation of Wang et. al.Slide17
Thank you