Numerical and experimental study on the effect of obstacles on DDT process
The present paper deals with the experimental and the numerical findings of break- ing down and re-initiating mechanism of detonation in a tube with obstacles. Experiments are performed for the stoichiometric oxyhydrogen mixture diluted with nitrogen using ICCD cam- eras and pressure transducers. Numerical simulations are also performed for compressible Euler equations to be integrated by a non-MUSCL modified flux type TVD scheme to find out the detailed mechanism of detonation breakdown and its re-initiation. Two types of obstacle arrays are applied to see their effect on detonation propagation and interaction with them; staggered array and symmetry array. The results show that numerical simulation explains a qualitative agreement with the experimental results in pressure profiles and that detonation breaks down at a point between the first obstacle and the second one and re-initiates afterwards. The staggered array gives ignitions behind obstacles and at the interaction between two reflected waves from the first and the second obstacle. On the other hand the symmetry array gives a symmetrical propagation to combustion wave to cause jet ignition. Detonation intensity is stronger when dilution is weaker as known generally.
KeywordsPressure Profile Combustion Wave Blockage Ratio Compressible Euler Equation Stagger Array
Unable to display preview. Download preview PDF.
- 2.W.R. Chapman and R.N.V. Wheeler: J. Chem. Soc. (London) 2139, (1926); J. Chem. Soc. (London) 38, (1927)Google Scholar
- 3.K.I. Shechelkin: J. Exp. Theo. Phys. (USSR) 10, 823 (1940)Google Scholar
- 4.M.V. Evans, M.D. Scheer, L.J. Schoen, and E.L. Miller: ‘A Study of High Velocity Flames Developed by Grids in Tubes’. In: Proc. 3rd Symp. (Int.) on Combustion, The Combustion Institute, Pittsburgh, 1949, pp. 168–185Google Scholar
- 5.H. Gg. Wagner: ‘Some Experiments about Flame Acceleration’. In: First Int. Specialist Meeting on Fuel-Air Explosion, Montreal: University of Waterloo Press SM Study No. 16, 1981, pp.77–99Google Scholar
- 7.B.H. Hjertager, K. Fuhre, S.J. Parker, and J.R. Bakke: ‘Flame Acceleration of Propane-Air in a Large-Scale Obstructed Tube’. In: The 9th Int. Colloq. On Dynamics of Explosion and Reactive Systems, Poitiers, 1983 Google Scholar
- 8.J.H. Lee: ‘First Flames and Detonations’. In: The Chemistry of Combustion Processes, ed. by M. Thompson, Sloane ACS Symp. Series 249, (1984) pp.119–150Google Scholar