The Influence Of Main Structural Parameters Of Double Intake Port On Flow Performance In Diesel Engine

The flow performance of gas handling system in diesel engine is vital to the quality of burning process. The main object of this thesis is double intake port in diesel engine and the main work is to research the influence of structural parameters on flow performance in double-tangent-port and mixed-port (composed of helix port and tangent port). The following works are included in the thesis:Based on the reading of various literatures, the research technique and production for the flow in port-cylinder system of internal-combustion engine were summarized. The flowing process in port-cylinder system of double-tangent-port model was simulated with CFD software FIRE. The calculation result matches the steady flow experiment result well.The drawing software UG was employed to design the mixed-port model that included helix port and tangent port. The flowing and interfered instance in double intake port model was studied with simulation. The flowing trait between mixed-port and double tangent port was also compared. The result shows that the vortices in mixed-port are bigger than that in double tangent port, while the discharge coefficient is smaller.The main structural parameters of double intake port were modified, and then the flow instance in modified model was simulated. It got the flowing traces and the distributing pictures of the velocity in port-valve-cylinder system. It studied the influence of various structural parameters on flow performance in double intake port. Main conclusions are as following: Port eccentricity and angle between two ports have some influence on average swirl ratio, and valve cone angle has biggish influence on both average discharge coefficient and average swirl ratio. When modify the ratio of minimum cross-section to inner seat section, helical ramp angle, or bottom ramp angle of helix port, the average discharge coefficient will decrease, while the average swirl ratio will increase, and helical ramp angle has the greatest influence on average swirl ratio.The above conclusions are helpful to know the intake port performance and vortices structure in double intake port, as well as the design and improvement for double intake port of diesel engine.