Assessment of Turbulence Models for Engine Intake and Compression Flow Analysis

Abstract ： Many turbulence models have been developed in order to analyze the flow characteristics in an engine cylinder. Watkins introduced k-e turbulence model for in-cylinder flow, and Reynolds modified turbulence dissipation rate by applying rapid transformation theory, Wu suggested k-e-τ turbulence model in which length scale and time scale are separated to introduce turbulence time scale, and Orszag proposed k-e RNG model. This study applied the models to in-cylinder flow induced by intake valve and piston moving. All models showed similar flow fields during early stage of intake stroke. At the end of compression stroke, κ-e Watkins, κ-e Reynolds and κ-e RNG predicted well second and third vortex, especially κ-e RNG produced new forth vortex near central axis at the lower part of cylinder which was not predicted by the other models. Key words ：Turbulence model(난류모델), Engine intake and compression(엔진 흡입․압축), Flow analysis(유동해석) †교신저자(한국해양대학교 기계정보공학부, E-mail:khpark@hhu.ac.kr, Tel: 051)410-4367)* 신라공업고등학교 교사