Experimental and Numerical Simulation of the Effect of the Inlet Valve Shroud and Orientation Angles on Flow Characteristic under Steady Flow Conditions

Air swirl motion inside the engine cylinder improves the air-fuel mixing which has a great effect on the thermal efficiency, soot formation, and engine emissions. In this work, experimental and numerical investigations were performed on a diesel engine cylinder having a configuration of a helical-spiral inlet port and shrouded valve under steady flow condition. Four shrouded valves having different shroud angles were used; the shroud angles are 90 deg, 120 deg, 150 deg, and 180 deg. With each shroud angle, four orientation angles were selected; they are 0 deg, 30 deg, 60 deg, and 90 deg. The experimental and numerical analyses were performed under a constant vacuum pressure of 350 mm H₂O. In addition, numerical analysis, using the SST k − ω model, is performed on the engine cylinder using shrouded valve having shroud angle of 90 deg as a case study. The results showed that using of shrouded valve decreases the mass flow rate and the discharge coefficient while it increases the swirl number at all valve shroud and orientation angles except valve shroud of 180 deg and orientation angle of 90 deg. The numerical simulation analysis showed reasonable agreement with the experimental work. Therefore, the virtual test rig can be used for studying the influence of the valve and the port configurations on the flow characteristics.