Numerical Investigation Of Throttle Valve Flow Characteristics For Internal Combustion Engines

Gas exchange processes of internal combustion engines have an important effect on engine performances, emissions of pollutants and noise. To control the engine output torque by the intake airflow restriction, a throttle valve must be installed between the air cleaner and the intake manifold. Due to the complex nature of this unit geometry and the resulting flow field, a 3D flow model would be indispensable to predict precisely the relative flow behavior. Actually, CFD codes and models are used in the design starting point. One of the major advantages of numerical investigation of turbulent flows is the capability to change easily the geometry, dynamic and thermodynamic parameters for the problem treated. Hence, we can study the effect of these parameters avoiding repetition of experimentation, which is usually time consuming and costly. However, the experimental measures will stay and forever the only way to validate the numeral calculations. To develop this subject, numerical investigation and analytical analysis have been proposed in this paper. First, we have used existing mathematical model (Barré de Saint Venant model), to check if it can be applied to study this kind of flow. Simultaneously, 3D investigation was carried out to study the mean and turbulent flow characteristics. Then, results obtained from the simulation model are compared with those obtained analytically and experimentally. Acceptable agreement is noticed from the use of the 3D viscous model in conjunction with the Barré de Saint Venant model. Future recommendations for modeling improvements were suggested in the end of this paper to correct the quasi-steady (or BSV) model. Keywords— internal combustion engines, throttle valve, CFD simulation, modeling methods, fluid flow, turbulence models