Development and validation of a chemical reaction solver coupled to the FLASH code for combustion applications

Abstract

We report on modifications to the widely used astrophysical code, FLASH (Fryxell, Olson et al. 2000) that enable accurate simulations of chemically reacting flows with heat addition. The enhancements to FLASH include the implementation of extensive Hydrogen-air and Methaneair chemistry through multiple, detailed mechanisms (Smooke 1991; Katta and Roquemore 1995; Mueller, Kim et al. 1999; Billet 2005), accomplished by building on the existing infrastructure of nuclear reaction network solvers. The chemical reaction network is represented as a system of coupled ODEs, that are then solved either through the Kaps-Rentrop (Rosenbrok) method(Kaps and Rentrop 1979) or the Bader-Deuflhard method (Bader and

Combustion Processes in Interfacial Instabilities

“…As stated in ref. [62], S was chosen to be 3, which yields a value of 2.5e-2 cm for the initial interface thickness. As a result of the interaction between the shock wave and the bubble, shock waves travel towards the right outlet boundary at x=3 cm.…”

“…FLASH is also capable of operating in both ILES [60] (implicit large eddy simulation) and DNS [61] (direct numerical simulation) modes, where the former approach is suited to handle shocks and sharp interfaces [57,58], while the latter approach is preferred in describing small-scale features in turbulence [61]. Recent modifications [62,63] to the FLASH code by the authors have rendered it capable of describing a wide range of chemically reacting flows of relevance to combustion phenomena as they occur in realistic applications, and are summarized below, while additional details are available in refs. [57,58,62].…”

“…Recent modifications [62,63] to the FLASH code by the authors have rendered it capable of describing a wide range of chemically reacting flows of relevance to combustion phenomena as they occur in realistic applications, and are summarized below, while additional details are available in refs. [57,58,62].…”

“…The results of an extensive validation and convergence study were reported in ref. [62] for several flows through comparison with analytical solutions, and published numerical and experimental data. Our validation cases included advection of reacting and non-reacting fronts in 1D and 2D [66], comparison with experimental data of laminar premixed flames in a Bunsen burner configuration [67,68] and comparison with DNS of shock-driven combustion of a spherical bubble [69].…”

“…We summarize the results from one such study for the shock-accelerated RM problem described in Section 3. A sinusoidally perturbed (wavelength, λ = 6 cm), single-mode interface separating hydrogen (300 K) and oxygen (1625 K) was accelerated by a Mach 1.2 shock traversing from the light (H 2 ) to heavy (O 2 ) fluid (Atwood number = 0.5) in an aspect ratio 6 numerical shock tube (see [62] for details). The impulsive acceleration of the interface (ΔU)…”