The Effect of Curve Cylinder Liner on in-Cylinder Tumble Flow Motion Characteristic using CFD Port Flow Simulation

Abstract

One crucial task in determining maximum engine output performance is evaluating its respiration capacity. While the steady state flow bench is a commonly used tool in the automotive industry, computational fluid dynamics (CFD) provides a more detailed and comprehensive analysis of flow characteristics within the cylinder compared to experiments. The objective of this paper is to investigate the impact of curve cylinder liners on flow motion characteristics. Using both experimental and CFD methods, this study examines the effect of curve liners on tumble flow motion at different valve lifts and pressure differences. Scalar maps were analysed to understand the behaviour of flow, and the findings indicate that the air velocity measured at the intake port was consistent between both methods, permitting further CFD analysis. Results show that air velocity measured at the intake port was consistent between both methods, allowing for further CFD analysis. Differences in average velocities between liners were insignificant at lower valve lifts, but noticeable at higher valve lifts, with up to a 15.67% difference recorded when the curve wall assisted air flow, resulting in an increase in air rotational strength. In addition, curve liners produced 11.44% and 10.09% more turbulent kinetic energy (TKE) than straight liners for 150mmH2O and 600mmH2O, respectively, with Plane 2 exhibiting the most significant difference in average TKE. Finally, the tumble ratio produced within the curve cylinder was significantly higher than the slider cylinder liner, with differences of up to 17.03% and 11.04% found at higher valve lift (5.4mm) for 150mmH2O and 600mmH2O, respectively.