The Study Of Base On CFD To Evaluate Andimprove Diesel Intake Port

There is a direct relationship of the swirl ratio and volumetric efficiency about the engine. The cylinder gas mixture formation? combustion? engine emissions and engine performance have a significant relationship with the intake port structure.Intake port is calculated by Fire. Study on the relationship between the flow coefficient and swirl ratio in constant pressure difference. The research showed that in the constant pressure difference, flow coefficient and swirl ratio will be increased with the valve lift. When the valve lift is less than 4 mm, the opening of the valve effect discharge coefficient obviously, when Valve lift is greater than 8 mm, the opening of the valve has less effect on the flow coefficient.It is found that the simulation values and the experimental values have a good consistency through the analysis. In the different lift the maximum deviation of Swirl ratio is 14%, the flow coefficient is 12%. Although the calculation deviation also needs to be reduced, but the calculated values and experimental values have the same trend, it is proved that the feasibility of evaluation and optimization intake port by CFD.Through the study of combination port of helical and tangential, it is found that when the valve lift is less than 5mm the swirl ratio value of combination port is between the helical port and tangential port, when the valve lift is greater than 5mm the swirl ratio value of combination port is smallest. At the same time in different valve open the flow coefficient value of combination port is also low.Through the study of flow coefficient in difference pressure it is found that in different valve opening, when the difference pressure is small, the flow coefficient value maximum decrease is l0%; when the difference pressure is big, the flow coefficient value maximum decrease is l5%; if in the larger valve opening the flow coefficient value decreased more obviously. With the pressure increasing, the gas velocity increasing, at the same time the flow rate distribution is not uniformity. In the high difference pressure the gas velocity will reach 1 Mach.Through the analysis of the distribution of pressure field and turbulent kinetic energy field, we can find the nearby area of the port is an important part of the flow field. To optimize the intake port, first consideration is the region nearby the valve.Based on the analysis of internal flow field information about the intake port, Aiming at the problems found in actual production process, we calculate the intake port by CFD. We can find out some existing problems and give some suggestions to optimize the diesel engine intake port. It has reference value for the future of the intake port design.