Abstract:The scalar filtered mass density function model is further extended and employed for large-eddy simulations of high-speed turbulent mixing and reacting flows. The model is implemented through a hybrid mathematical/ computational methodology. In this methodology, the filtered compressible Navier-Stokes equations in a curvilinear coordinate system are solved with a generalized, high-order, multiblock, finite difference scheme for the turbulent velocity and pressure. However, the scalar mixing and combustion are … Show more
“…The gas phase is treated by a hybrid methodology. The compressible LES equations for velocity and pressure are solved by high-order compact finite difference methods via a grid-based Eulerian multiblock flow solver [16,51,52]. The scalar field (i.e.…”
Section: Mathematical and Computational Modelmentioning
confidence: 99%
“…Li et al [22] extended the original FMDF to two-phase flows. Banaeizadeh et al [52] included the compressibility effects in the scalar FMDF methodology.…”
Section: Two-phase Filtered Mass Density Functionmentioning
The two-phase filtered mass density function (FMDF) method is employed for large eddy simulation (LES) of high speed evaporating and combusting nheptane sprays using simple (global) and complex (skeletal) chemical kinetic mechanisms. The resolved fluid velocity and pressure fields are obtained by solving the filtered compressible Navier-Stokes equations with high-order Eulerian finite difference methods. The liquid spray and gas scalar (temperature and species mass fractions) fields are both obtained by Lagrangian stochastic models. The chemistry calculation is accelerated by incorporating the parallel in situ adaptive tabulation (ISAT) method. There are two-way interactions among Eulerian and Lagrangian fields. Simulations of evaporating sprays with and without combustion indicate that the two-phase LES/FMDF results are consistent and compare well with the available experimental data at different gas temperatures and oxygen concentrations. The spray controlled flame tends to move away from a diffusion flame structure toward a premixed one as the oxygen concentration decreases and/or the ambient gas temperature increases because of changes in spray-induced turbulence and mixing. The LES/FMDF results for ignition delay show more sensitivity to the chemical kinetic model at lower gas temperatures due to slower reaction and stronger turbulence-chemistry interactions. The liftoff length is less sensitive to the kinetics.
“…The gas phase is treated by a hybrid methodology. The compressible LES equations for velocity and pressure are solved by high-order compact finite difference methods via a grid-based Eulerian multiblock flow solver [16,51,52]. The scalar field (i.e.…”
Section: Mathematical and Computational Modelmentioning
confidence: 99%
“…Li et al [22] extended the original FMDF to two-phase flows. Banaeizadeh et al [52] included the compressibility effects in the scalar FMDF methodology.…”
Section: Two-phase Filtered Mass Density Functionmentioning
The two-phase filtered mass density function (FMDF) method is employed for large eddy simulation (LES) of high speed evaporating and combusting nheptane sprays using simple (global) and complex (skeletal) chemical kinetic mechanisms. The resolved fluid velocity and pressure fields are obtained by solving the filtered compressible Navier-Stokes equations with high-order Eulerian finite difference methods. The liquid spray and gas scalar (temperature and species mass fractions) fields are both obtained by Lagrangian stochastic models. The chemistry calculation is accelerated by incorporating the parallel in situ adaptive tabulation (ISAT) method. There are two-way interactions among Eulerian and Lagrangian fields. Simulations of evaporating sprays with and without combustion indicate that the two-phase LES/FMDF results are consistent and compare well with the available experimental data at different gas temperatures and oxygen concentrations. The spray controlled flame tends to move away from a diffusion flame structure toward a premixed one as the oxygen concentration decreases and/or the ambient gas temperature increases because of changes in spray-induced turbulence and mixing. The LES/FMDF results for ignition delay show more sensitivity to the chemical kinetic model at lower gas temperatures due to slower reaction and stronger turbulence-chemistry interactions. The liftoff length is less sensitive to the kinetics.
“…Three-dimensional filtered Navier-Stokes equations for compressible flows in a generalized curvilinear coordinates system (n; g; f) is represented in the following compact form [37,38] @JU @t…”
Section: Governing Equations and Numerical Methodsmentioning
confidence: 99%
“…Earlier applications of the FMDF/FDF model (FDF or filtered density function is the constant-density version of the FMDF) were for fundamental problems and were focused on the development and testing of various formulations of the model. The scalar FDF was considered in Colucci et al [29], the scalar FMDF in Jaberi et al [30]; Jaberi [31]; James and Jaberi [32]; Sheikhi et al [33]; Yaldizli et al [34]; Nik et al [35]; Yilmaz et al [36]; Banaeizadeh and Jaberi [37]; Afshari et al [38]; Afshari and Jaberi [39], the velocity FDF in Gicquel et al [40], the velocity-scalar FDF in Sheikhi et al [41] and the velocity-scalar FMDF in Sheikhi et al [42]; a review of these works is provided in Givi [43] and Madnia et al [44]. The LES/FMDF used in this study is implemented via a hybrid Eulerian-Lagrangian numerical scheme.…”
“…A number of additional cases have been simulated with LES/FDF methods including high-speed mixing [167], flows with shocks [168], and combusting flows [169][170][171][172]. One of these interesting cases considered the LES of turbulent nonreacting and reacting flow in an axisymmetric dump combustor [172].…”
Section: Les/filtered Density Function Methods For High-speed Reacmentioning
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.