Research On Calculation Of3D Flow For Pulse Charging System Of Internal Combustion Engine

In recent years, the energy problem has become increasingly intractable along with the overexploitation from nature, the requirements for performance of the power machinery are becoming more and more stringent. Pulse exhaust system of internal combustion engine can make full use of the exhaust energy and increase the density of the intake air, and improve the economy performance of the internal combustion engine. At the same time, the pulse exhaust system is responsive to the vibration of the pressure of the exhaust gas, which can improve the acceleration characteristics and torque characteristics of the internal combustion engine. Therefore, Pulse exhaust system is widely used on the internal combustion engine of the vehicle. Traditional design methods for exhaust system of internal combustion engine are based on experience and experiments, which have been unable to meet the current demand of the design of IC engine. The modern computer technology makes it possible to calculate the performance of internal combustion engine, which can significantly save time and cost.Boundary conditions of Pulse exhaust system were not easily got by experiment, therefore, a GT-Power simulation result was used as boundary conditions of the high-power six-cylinder diesel engine. The parameters needed in the model were determined through experiments and empirical formula. Different conditions of the engine working process were simulated in this study. The accuracy of the model was confirmed by comparing the calculation data with the experiment datain different conditions of the engine, which provided the boundary conditions for the model of the pulse exhaust system.A physical model was drawn as the actual shape of the exhaust pipe of the engine. The three-dimensional flow calculation model used the polyhedral mesh provided by Fluent. The turbulence model used the standard model, boundary conditions were decided by the simplified mass flow curves, which were got by one-dimensional performance calculation. The flow mechanism of pulse exhaust system was discussed by analyzing open, closing points,opening points and max mass flow points of exhaust manifold.