Computational fluid-dynamics could be useful to improve these components, providing an insight into the cylinder air motion together with an estimation of the flow coefficient for new intake port configurations. The maximum cell size used is 3 mm, while the number of cells is between and thousands for all the adopted meshes. Most of the air incoming within the cylinder comes from the shortest duct ports, while the other one is mainly used to create the air swirl motion evidenced in Figure 10 b. Several oper- ating conditions were considered; in particular, the range from rpm to rpm was covered at full load with a step of rpm. It is very important that the total domain mass is conserved after each remapping phase. Multiphase Flows with Droplets and Particles. Theoretical and Numerical Combustion.

The rhoSimpleFoam solver was used to perform steady-flow calculations and the Table 2 displays the main control parameters of the simulation. The reactive mixture in each computational cell is treated as a closed system. Then the solution is mapped from the actual source mesh to the following target mesh. The contribution of Daniele Ettorre to the Diesel combustion modeling section is grate- fully acknowledged. To attain success, such simulations need, in particular, well elaborated Computational Fluid Dynamics CFD software, as well as advanced predictive models of turbulent burning.

Furthermore, layers of cells are added and removed close to the piston surface.

openfoam thesis combustion

The operation-splitting technique increases significantly the computational time, mak- ing use of detailed chemistry. Total pressure and fixed temperature are imposed at the intake ports, fixed pressure at the exhaust port.


The rhoSimpleFoam solver was used to perform steady-flow calculations and the Thesie 2 displays the main control parameters of the simulation. To keep an optimum mesh size and avoid grid distor- tions close to the valves, a combination of different topological changes is used to add or remove cell layers, to deal with sliding mesh interfaces and the valve closure event. Mesh quality for each target mesh at the beginning and at the end of its crank angle interval. The Table 7 shows the initial condi- tions combustio the computational domain.

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Atomization and Spray Technology, Vol. The next step is the simulation of the gas exchange phase.


Journal of Vibration and Acoustics, Then the compression and combustion phases will be simulated, accounting for the liquid fuel spray injection using the models implemented in [19]. Both models predict correctly the lift-off dependency on EGR and mixture temperature [49].

openfoam thesis combustion

The engine has one exhaust port and five scavenging ports, with symmetrical design. The code already includes most of the widely used sub- models for spray breakup, fuel injection, droplet collisions, evaporation and turbulent dispersion.

Exploiting ISAT to solve the equations of reacting flow. Show downloadable dissertations only. A last application regards the coupling of Open- FOAM with a 1D fluid-dynamic code, Gasdyn, developed by the authors to simulate the whole engine cycle. However in certain points some attenuation peaks are not well captured as well as transparency frequencies, whereas the coupled approach predicts a transmission loss which globally agrees fairly well with the measured one.

Internal Combustion Engine Fundamentals.

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The presence of moving boundaries piston and valves requires to move efficiently the grid points, to keep the mesh quality high and avoid non-orthogonality and skewness errors. Inlet temperature was theeis to K. Combustion Science and Technology, Geometry, operating conditions and computational mesh for thesiss simulated two-stroke engine.


Remember me on this computer. Both the Kelvin-Helhmoltz and Rayleigh-Taylor mechanisms are accounted for to model the spray breakup [46].

Computed velocity field during the intake stroke for the Mitsubishi GDI en- gine. Kpenfoam motion is handled by mesh deformation and layering, with port section remaining fixed for the entire simulation. The scavenging process is summarized comubstion Figures 19 a – d where the residual gas distribution is illustrated at four different crank angles. Each mesh is used until its resolution becomes too coarse or its quality in terms of non-orthogonality and skewness do not strongly worsen. Geometry data of the Mitsubishi-GDI engine studied.

In particular, to avoid the generation of instabilities, the interface between the two domains has to be placed in regions where the flow can be reason- ably considered one-dimensional. Concerning Diesel combustion modeling, the au- thors are currently evaluating two different models: SAE Technical paper,April Error Analysis and estimation for the finite volume method with applications to fluid flows.

openfoam thesis combustion

Residual gas distribution during the scavenging process.