Flow Analysis Through a High-Performance SI-Engine Cylinder Head Intake Port

Abstract

The use of spark-ignited (SI) production-style vehicle engines in high-performance applications is a growing trend in the aftermarket performance industry. However, the use of economically designed components, specifically cylinder heads, presents challenges when used in this manner. The study of flow through a cylinder head is a topic of extensive research where complex flow patterns have made modelling and computer simulation challenging. A variety of approaches have been employed including simplifying model assumptions, different boundary conditions, different meshing strategies, and different turbulence models. The focus of this research is modification of the air intake port geometry of a VR38DETT engine in order to increase the volumetric flow rate past a current limit of 330.4 CFM at 0.700” valve lift, which has been achieved by porting methods alone. Using SolidWorks, a computational fluid dynamics model was developed, verified, validated, and analyzed. The modelling methodology was verified using a mesh convergence study of the pressure drop along a pipe with a bend. Also, the bend loss coefficient was compared to published values for different ratios of the centerline radius of the bend to the internal pipe diameter. The model was then validated using steady-state flow bench test data. Results of the analysis indicate that the cylinder head can achieve a flow rate 5.15% above the current limit when the port geometry is enlarged and the short-side radius is increased, only in support of a cooling passage geometry change.