Simulation Study Of High Pressure Difference Inlet Port Based On AVL-Fire

The intake system has a very important effect on the economy,performance and emissions of the engine.The main influence factors of the intake system include the gas flow quantity in the cylinder,the distribution of gas velocity in the cylinder,the swirl and turbulence formed in the intake process.Before the advent of computer simulation,The intake port was tested and experimented on a steady flow test rig,then modified and tested repeatedly to reach a ideal intake port model.The total development work of intake port was time-consuming and expensive.With the improvement of engine strength level,the pressure drop of intake port increases with the engine speed becoming higher and higher,so is the cost of steady flow test rig with high pressure drop.In addition,only macro-information of the intake port can be reported with experiment result,the micro-information of intake flow cannot be viewed.Nowadays,the method of 3d numerical simulation of the intake system can study both the macro-information including gas movement characteristics and the micro-information of the airflow,which makes it get more attention by relevant researchers.The intake port was first experimented on a steady flow test rig with high pressure drop,the 3D geometry model was then built with Pro/E.AVL-FIRE was used to mesh the intake port and steady flow is simulated to research the intake flow characterics.The simulation results were validated and verified with the steady flow test results within acceptable error.After validation and verification,different intake pressure,different pressure drop and different valve lift were simulated to acquire the flow coefficiency and the information of pressure,streamline and velocity in cylinder.The simulation method and results in this research paper is of great value in modeling and developing the diesel engine to reach a optimal diesel combustion.and then through the Pro/E to establish the same as the high pressure differential airway steady flow test rig of airway model and using AVL software Fire-the meshing of the diesel engine inlet and three-dimensional numerical simulation,studied the diesel engine inlet and gas in the cylinder motion characteristics.Firstly,the numerical simulation results were verified by using the flow coefficient of the air passage calculated by the test bed.Thereafter respectively to different inlet pressure and airway pressure differential and valve lift model for numerical simulation of the flow coefficient under different working conditions and the inlet and the pressure inside the cylinder,air flow trace,velocity distribution,and so on information,and the analysis of these information to induce gas at the inlet and the characteristics of the movement in the cylinder,affect the flow coefficient of the size and the crux of the mixing degree of gas inside the cylinder.The research methods and results of this paper are of great significance for the research and improvement of combustion in high-intensification diesel engines,and for the practical value of model application and engineering development of diesel engines.