Simulation of Improvements to Flow Characteristics in Diesel Helical Intake Port by Incorporating Guide Vanes into the Intake Manifold

Swirl ratio is an important index to evaluate the inlet flow characteristics of the diesel engine. The higher intake swirl can improve the atomization and mixture of fuel and air, resulting in higher thermal efficiency. In order to enhance the swirl intensity of the diesel engine with a semi-open combustion chamber, a guide vane device is installed in front of the engine’s helical intake port. The numerical simulation of the cylinder intake process is carried out by using the CFD software XFlow with the meshless approach. Inlet models with guide vanes of different heights, lengths, and twist angles, and without vanes at different valve lifts are simulated respectively, then the swirl ratio is calculated for comparative analysis. The results show that the swirl ratio of the inlet with guide vane can be significantly improved, and the maximum can be increased by 24.69%.