Abstract: This paper discusses the fundamentals of an engine ignition system modeling using bond graph approach and its mathematical interpretation and physics for the different stages of motor operation. Other topics covered in this paper show that fault detection and localization of the defects in the engine ignition system with lighting presented by its bond graph model. One of the original points is that this work treated the utilization of fault detection and isolation method (FDI). A new method is proposed to avoid the exploration of all the combinations for its application to the diagnostic of this system operation and to determine the gravity of a detected failure. The causal paths help us in this procedure in order to generating the analytical redundancy relations ARR at each step from constitutive and structural junction relations. This is shown through an algorithm for monitoring the system by sensors placements on the corresponding bond graph model. The diagnosis performances are controlled by a sensitivity analysis of these residues, making it possible to define indices of sensitivity, and detectability indices of the defects.

Key words: Modeling, Bond Graph, Engine ignition system, Sensors Placement, Detection, Localization.

Abstract: The performance of two different turbulence closure models in the prediction of turbulent swirling flow is presented .The models evaluated are the Reynolds stress transport model (RSM_SSG) and the Kw_SST model . This study is a direct comparison between numerical simulation and measurements of the overall flow variables mean and kinetic turbulent of a swirled turbulent flow with different sections. The comparison of the calculation results with measurements confirmed the inadequacy of two models. This handicap is related to the complexity of the structure of the flow (unsteady, three-dimensional, various turbulence scales...)

Key words: Swirl, Turbulence, Simulation.

Abstract: Forced convection heat transfer inside a porous micro duct is performed to investigate the effects of porous material on the heat transfer rate. The flow in the porous material is described by the Darcy- Brinkman- Forchheimer model. The assumption of local thermal non equilibrium (LTNE) condition is adopted for heat transfer and viscous dissipation effects are included in the energy equation of the fluid phase. The obtained governing equations are solved using the Lattice Boltzmann Method (LBM). Knudsen, Eckert and Darcy numbers are selected as the influence parameters. The computational simulations are done for different Knudsen numbers (Kn ), Darcy number ( Da) and Eckert number ( Ec). It is found that both fluid and solid temperatures increases as the Kn decreases, Da decreases and Ec increases. However, the augmentation in Da is related to the important fluid friction effects which decrease the temperature gradient.

Key words: Porous media, Local thermal non-equilibrium, Lattice Boltzmann Method, micro duct.