The filtered mass density function (FMDF) model (Jaberi et al. 1999 [1]) is employed for large eddy simulations (LES) of “high speed” partially-premixed methane jet flames with the “flamelet” and “finite-rate” kinetics models. The FMDF is the joint probability density function (PDF) of the scalars and is determined via the solution of a set of stochastic differential equations. The LES/FMDF is implemented using a highly scalable, parallel hybrid Eulerian–Lagrangian numerical scheme. The LES/FMDF results are shown to compare well with the experimental data for all flow conditions when “appropriate” reaction and mixing models are employed.

10aFiltered mass density function; PDF methods; Monte-Carlo simulations; Methane jet flames10aLES1 aYaldizli, M.1 aMehravaran, K.1 aJaberi, F.A. uhttps://icer.msu.edu/research/publications/large-eddy-simulations-turbulent-methane-jet-flames-filtered-mass-density-000963nas a2200289 4500008004100000245007500041210006900116300001200185490000900197653001400206653002500220653003000245653002400275653002200299653002300321653001300344653001400357653001500371653003700386653001900423653004100442100001900483700001900502700002600521700001700547856010900564 2010 eng d00aLocal and Global Radiative Feedback from Population III Star Formation0 aLocal and Global Radiative Feedback from Population III Star For a128-1330 v129410aDistances10aPopulation III stars10aPre-main sequence objects10aprotostellar clouds10aradial velocities10aradiative transfer10aredshift10aredshifts10ascattering10aspatial distribution of galaxies10astar formation10ayoung stellar objects and protostars1 aO'Shea, B., W.1 aWhalen, D., J.1 aWhalen, Bromm, {D. J.1 aYoshida}, N. uhttps://icer.msu.edu/research/publications/local-global-radiative-feedback-population-iii-star-formation01283nas a2200133 4500008004100000245009500041210006900136260005900205520071100264100001700975700001900992700001701011856012101028 2009 eng d00aLarge-Eddy Simulations of Turbulent Methane Jet Flames with Filtered Mass Density Function0 aLargeEddy Simulations of Turbulent Methane Jet Flames with Filte aAnn Arbor, MichiganbThe Combustion Institutec05/20093 aThe filtered mass density function (FMDF) model (Jaberi et al. 1999 [1]) is employed for large eddy simulations (LES) of “high speed” partially-premixed methane jet flames with the “flamelet” and “finite-rate” kinetics models. The FMDF is the joint probability density function (PDF) of the scalars and is determined via the solution of a set of stochastic differential equations. The LES/FMDF is implemented using a highly scalable, parallel hybrid Eulerian–Lagrangian numerical scheme. The LES/FMDF results are shown to compare well with the experimental data for all flow conditions when “appropriate” reaction and mixing models are employed.

1 aYaldizli, M.1 aMehravaran, K.1 aJaberi, F.A. uhttps://icer.msu.edu/research/publications/large-eddy-simulations-turbulent-methane-jet-flames-filtered-mass-density01908nas a2200133 4500008004100000245008100041210006900122260003200191520138900223100001101612700001701623700001701640856011701657 2008 eng d00aFiltered Mass Density Function for Numerical Simulations of Spray Combustion0 aFiltered Mass Density Function for Numerical Simulations of Spra aReno, NevadabAIAAc01/20083 aThis paper briefly describes our recent efforts on the modeling and numerical simulations of two-phase turbulent reacting flows in realistic combustion systems with a new large-eddy simulation (LES) model. The model is constructed based on the two-phase extension of scalar filtered mass density function (FMDF) and a Lagrangian-Eulerian- Lagrangian mathematical/numerical methodology. In this methodology, the “resolved” fluid velocity field is obtained by solving the filtered form of the compressible Navier-Stokes equations with a high-order finite difference scheme. The liquid (droplet) phase and scalar (temperature and species mass fractions) fields are both obtained by stochastic Lagrangian models. There are two-way interactions between the phases and all the Eulerian and Lagrangian fields. The LES/FMDF is used for systematic analysis of turbulent combustion in the spray-controlled dump combustor and double-swirl spray burner for various flow and spray parameters. The effects of fuel type, spray angle, mass loading ratio, droplet size distribution, fuel/air composition, wall, and inflow/outflow conditions on the combustion are investigated. It has been found that the main features of the turbulence and combustion are modified by changing the inflow/outflow conditions. The LES/FMDF results also confirm the significance of the spray parameters.

1 aLi, Z.1 aJaberi, F.A.1 aYaldizli, M. uhttps://icer.msu.edu/research/publications/filtered-mass-density-function-numerical-simulations-spray-combustion02163nas a2200193 4500008004100000245008900041210006900130260001200199300001200211490000800223520143600231653002801667653008201695100001701777700001701794700001901811700001701830856012201847 2008 eng d00aThe Structure of Partially-Premixed Methane Flames in High Intensity Turbulent Flows0 aStructure of PartiallyPremixed Methane Flames in High Intensity c09/2008 a692-7140 v1543 aDirect numerical simulations (DNS) are conducted to study the structure of partially premixed and non-premixed methane flames in high-intensity two-dimensional isotropic turbulent flows. The results obtained via “flame normal analysis” show local extinction and reignition for both non-premixed and partially premixed flames. Dynamical analysis of the flame with a Lagrangian method indicates that the time integrated strain rate characterizes the finite-rate chemistry effects and the flame extinction better than the strain rate. It is observed that the flame behavior is affected by the “pressure-dilatation” and “viscous-dissipation” in addition to strain rate. Consistent with previous studies, high vorticity values are detected close to the reaction zone, where the vorticity generation by the “baroclinic torque” was found to be significant. The influences of (initial) Reynolds and Damköhler numbers, and various air–fuel premixing levels on flame and turbulence variables are also studied. It is observed that the flame extinction occurs similarly in flames with different fuel–air premixing. Our simulations also indicate that the CO emission increases as the partial premixing of the fuel with air increases. Higher values of the temperature, the OH mass fraction and the CO mass fraction are observed within the flame zone at higher Reynolds numbers.

10aDNS; Methane combustion10aturbulent reacting flows; partially premixed flames; reduced chemistry models1 aYaldizli, M.1 aMohammad, H.1 aMehravaran, K.1 aJaberi, F.A. uhttps://icer.msu.edu/research/publications/structure-partially-premixed-methane-flames-high-intensity-turbulent-flows01888nas a2200133 4500008004100000245008100041210006900122260003200191520138900223100001701612700001101629700001701640856009701657 2007 eng d00aFiltered Mass Density Function for Numerical Simulations of Spray Combustion0 aFiltered Mass Density Function for Numerical Simulations of Spra aReno, NevadabAIAAc01/20083 aThis paper briefly describes our recent efforts on the modeling and numerical simulations of two-phase turbulent reacting flows in realistic combustion systems with a new large-eddy simulation (LES) model. The model is constructed based on the two-phase extension of scalar filtered mass density function (FMDF) and a Lagrangian-Eulerian- Lagrangian mathematical/numerical methodology. In this methodology, the “resolved” fluid velocity field is obtained by solving the filtered form of the compressible Navier-Stokes equations with a high-order finite difference scheme. The liquid (droplet) phase and scalar (temperature and species mass fractions) fields are both obtained by stochastic Lagrangian models. There are two-way interactions between the phases and all the Eulerian and Lagrangian fields. The LES/FMDF is used for systematic analysis of turbulent combustion in the spray-controlled dump combustor and double-swirl spray burner for various flow and spray parameters. The effects of fuel type, spray angle, mass loading ratio, droplet size distribution, fuel/air composition, wall, and inflow/outflow conditions on the combustion are investigated. It has been found that the main features of the turbulence and combustion are modified by changing the inflow/outflow conditions. The LES/FMDF results also confirm the significance of the spray parameters.

1 aYaldizli, M.1 aLi, Z.1 aJaberi, F.A. uhttps://icer.msu.edu/filtered-mass-density-function-numerical-simulations-spray-combustion-001300nas a2200133 4500008004100000245007900041210006900120260005000189520079100239100001701030700001101047700001701058856009101075 2007 eng d00aA New Model for Large Eddy Simulations of Multi-Phase Turbulent Combustion0 aNew Model for Large Eddy Simulations of MultiPhase Turbulent Com aCincinnati, OhiobAIAA/ASME/SAI/ASEEc07/20073 aNumerical simulations of a spray-controlled lean premixed dump combustor are con- ducted via a two-phase large eddy simulation (LES) methodology. In this methodology, the velocity field is obtained by a high-order finite difference method. The subgrid gas- liquid combustion closure is based on the two-phase filtered mass density function (FMDF) method and the spray is modeled with a Lagrangian scheme. The effects of spray, fuel/air composition, and inflow/outflow conditions on the combustion are investigated. It has been found that the main features of the turbulence and combustion inside the dump combustor are very differently modified by the spray for different spray parameters. The LES/FMDF results also indicate the significance of the inflow and outflow conditions.

1 aYaldizli, M.1 aLi, Z.1 aJaberi, J.A. uhttps://icer.msu.edu/new-model-large-eddy-simulations-multi-phase-turbulent-combustion01659nas a2200145 4500008004100000020001800041245007700059210006900136260003700205520113400242100001101376700001701387700001701404856009201421 2007 eng d a0-7918-4803-500aNumerical Simulations of Two-Phase Turbulent Combustion in Spray Burners0 aNumerical Simulations of TwoPhase Turbulent Combustion in Spray aLas Vegas, NevadabASMEc09/20073 aThe complex interactions among turbulence, combustion and spray in liquid-fuel burners are modeled and simulated via a new two-phase Lagrangian-Eulerian-Lagrangian large eddy simulation (LES) methodology. In this methodology, the spray is modeled with a Lagrangian mathematical/computational method which allows two-way mass, momentum and energy coupling between phases. The subgrid gas-liquid combustion is based on the two-phase filtered mass density function (FMDF) that has several advantages over “conventional” two-phase combustion models. The LES/FMDF is employed in conjunction with non-equilibrium reaction and droplet models. Simulations of turbulent combustion in a spray-controlled double-swirl burner are conducted via LES/FMDF. The generated results are used for better understanding of spray combustion in realistic turbulent flow configurations. The effects of spray angle, mass loading ratio, fuel type, droplet size distribution, wall and inflow/outflow conditions on the flow and combustion are investigated. The LES/FMDF predictions are shown to be consistent with the experimental results.

1 aLi, Z.1 aYaldizli, M.1 aJaberi, F.A. uhttps://icer.msu.edu/numerical-simulations-two-phase-turbulent-combustion-spray-burners