The scalar filtered mass density function (FMDF) is further developed and employed for large-eddy simulations (LES) of high speed turbulent flows in complex geometries. LES/FMDF is implemented via an efficient, hybrid numerical method. In this method, the filtered compressible Navier-Stokes equations in curvilinear coordinate systems are solved with a generalized, high-order, multi-block, compact differencing scheme. Turbulent mixing and combustion are modeled with the FMDF. The LES/FMDF method is used for simulations of isotropic turbulent flow in a piston-cylinder assembly, the flow in a shock tube and a supersonic co-axial helium-air jet. The critical role of pressure in the FMDF equation when applied to compressible flows is studied. It is shown that LES/FMDF is reliable and is able to simulate compressible turbulent mixing and combustion in supersonic flows.

1 aLi, Z.1 aJaberi, F.A.1 aBanaeizadeh, A. uhttps://icer.msu.edu/research/publications/large-scale-simulations-supersonic-turbulent-reacting-flows01658nas a2200133 4500008004100000245006400041210006300105260005900168520114000227100002001367700001901387700001701406856010101423 2009 eng d00aLES/FMDF of Spray Combustion in Internal Combustion Engines0 aLESFMDF of Spray Combustion in Internal Combustion Engines aAnn Arbor, MichiganbThe Combustion Institutec05/20063 aThe two-phase filtered mass density function (FMDF) model is employed for large-eddy simulation (LES) of turbulent spray combustion in internal combustion (IC) engines. The LES/FMDF is implemented with an efficient, hybrid numerical method. In this method, the filtered compressible Navier-Stokes equations in curvilinear coordinate systems are solved with a generalized, high-order, multi-block, compact differencing scheme. The spray and the FMDF are implemented with Lagrangian methods. The LES/FMDF methodology has been used for simulations of turbulent combustion in a rapid compression machine (RCM) and in a direct-injection spark-ignition (DISI) engine. For both RCM and DISI engine, the complex interactions among turbulent velocity, fuel droplets and combustion are shown to be well captured with the LES/FMDF. The results for the DISI engine indicate that the size, velocity, evaporation and combustion of the sprayed fuel droplets are strongly affected by the unsteady, vortical motions generated by the incoming air during the intake stroke. In turn, the droplets are found to change the in-cylinder flow structure.

1 aBanaeizadeh, A.1 aSchock, Harold1 aJaberi, F.A. uhttps://icer.msu.edu/research/publications/les-fmdf-spray-combustion-internal-combustion-engines00471nas a2200121 4500008004100000245006500041210006500106260002000171100001600191700002000207700001700227856010500244 2008 eng d00aLarge Eddy Simulation of High Speed Turbulent Reacting Flows0 aLarge Eddy Simulation of High Speed Turbulent Reacting Flows aHawaiic12/20081 aZhaorui, Li1 aBanaeizadeh, A.1 aJaberi, F.A. uhttps://icer.msu.edu/research/publications/large-eddy-simulation-high-speed-turbulent-reacting-flows01959nas a2200157 4500008004100000020002200041245006000063210006000123260003800183520141500221100002001636700001601656700001701672700001501689856009701704 2008 eng d a978-0-7918-4327-700aLarge Eddy Simulations of Turbulent Flows in IC Engines0 aLarge Eddy Simulations of Turbulent Flows in IC Engines aBrooklyn, New YorkbASMEc08/20083 aA new computational methodology is developed and tested for large eddy simulation (LES) of turbulent flows in internal combustion (IC) engines. In this methodology, the filtered compressible Navier-Stokes equations in curvilinear coordinate systems are solved via a generalized, high-order, multi-block, compact differencing scheme and various subgrid-scale (SGS) stress closures. Both reacting and nonreacting flows with and without spray are considered. The LES models have been applied to a piston-cylinder assembly with a stationary open valve and harmonically moving flat piston. The flow in a direct-injection spark-ignition (DISI) engine is also considered. It is observed that during the intake stroke of the engine operation, large-scale unsteady turbulent flow motions are developed behind the intake valves. The physical features of these turbulent motions and the ability of LES to capture them are studied and tested by simulating the flow in a simple configuration involving a stationary valve. The flow statistics predicted by LES are shown to compare well with the available experimental data. The DISI configuration includes all the complexities involved in a realistic single-cylinder IC engine, such as the complex geometry, moving valves, moving piston, spray and combustion. The spray combustion is simulated with the recently developed two-phase filtered mass density (FMDF) model.

1 aBanaeizadeh, A.1 aAfshari, A.1 aJaberi, F.A.1 aSchock, H. uhttps://icer.msu.edu/research/publications/large-eddy-simulations-turbulent-flows-ic-engines