Ayushi Mishra, Krishnakant Agarwal,Mayank Kumar
Abstract: This paper uses the OpenFOAM Computational Fluid Dynamics (CFD) code to study the turbulent premixed flame propagation characteristics inside a partially open duct filled with obstacles. The simulations were performed using a two-dimensional model with realizable k-ε turbulence modelling and Flame Surface Density (FSD) model proposed by Weller et al. for Combustion modelling. The solver uses adaptive time stepping method coupled with a maximum value of the Courant number. Initially the simulations were carried out with first order upwind scheme for divergence terms, second order Crank Nicolson method for time discretization and PIMPLE solver (with outer correctors set to 200 with residual for outer correctors set to 10¬-4) for pressure-velocity coupling. The solution with these schemes resulted in impractical dependence of overpressure peak on the initial values of simulation parameters: turbulent kinetic energy ‘k’, initial time step size ‘Δt’, mesh size ‘Δx’ as well as maximum value for Courant number of the flow ‘maxCo’. The k values tested are 0.5, 0.1, 0.05 and 0.01, as at 0.01 the pressure peak was negligible and far delayed. Similar results have been obtained for above mentioned parameters. The discretization schemes were updated to a second order linear scheme for divergence terms and a first order Euler method for temporal terms. The pressure velocity coupling was updated to iterative PISO algorithm (PIMPLE in OpenFOAM, with outer correctors of three). The updated solver was then tested against the experimental results to analyse the dependence of pressure peak on the above-mentioned simulation parameters. It was found that the unexpected dependence on all the parameters was eliminated and the solver provided reasonably good qualitative agreement with the experimental results. Effect of each of the discretization schemes is also tested individually. .
Keywords: XiFOAM, Discretization Schemes, Premixed Propagating Flames, Simulation Parameters.
Date Published: July 15, 2024 DOI: 10.11159/jffhmt.2024.018
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