In order to analyze the Intake flow characteristics of a four-valve direct injection(DI) diesel engine, the experiments and numerical simulations were conducted to investigate the flow coefficient, swirl ratio and Intake flow interference of the following 4 combinations of Intake ports: (1) helical (left) and tangential (right), abbreviation; (2) tangential (left) and helical (right); (3) helical (left) and helical (right); and (4) tangential (left) and tangential (right). Results show that the relative flow coefficient and swirl ratio could be directly reflect the interference of combined Intake port, and when the ratio was close to 1, which showed that Intake port had less interference; and when the ratio was close to 0, which showed that the interference was serious. The relative flow coefficient of the 4 combinations of Intake ports has little difference, but the relative swirl ration had significant difference in the whole valve lift range. And there had little interference between adjacent Intake ports, but the swirl was strongly formed in cylinder at the maximum valve lift.

In this paper comparative flow field analysis of two Intake configuration i. e. Boundary Layer Diverter Intake and Diverterless Supersonic Intake is carried out based on dimensionless parameters under various flow conditions. Numerical analysis of aircraft Intake is a complex phenomenon which involves both external and internal flow analysis. In this research, both external and internal flow characteristics of Intake duct are analyzed in detail. A comprehensive mesh scheme is devised and implemented to accurately capture the flow behavior in external surrounding of Intake duct and flow passing through the Intake duct. The analysis is carried out at different flow conditions to analyze the flow behavior in subsonic and supersonic regimes. Engine design mass flow rate is used for accurate Intake analysis and results are validated with available literature. Boundary layer diversion and pressure recovery are examined for each Intake configuration and comparative analysis based on pressure recovery is carried out subsequently. The analysis reveals that at subsonic and transonic regimes, Boundary Layer Diverter Intake is much more effective than Diverter less Supersonic Intake, however, in supersonic regime Diverter less Supersonic Intake is found be to more effective. The research can further help in modifying/ improving the design of an existing Intake configuration for enhanced Intake efficiency.