A Mohammadebrahim - Ph. D. Candidate Department of Mechanical Engineering, Sharif University of Technology, Irankhodro Powertrain Co.
M.B Shafiei - Technology
S.K Hamnani - Professor, Department of Mechanical Engineering, Sharif University of Technology

This paper presents the comparison between measured and predicted results of the in-cylinder tumble flow and flow coefficient generated by a port-valve-liner assembly on a steady-flow test bench. In this study, Computational Fluid Dynamics (CFD) methods were employed to gain further insight into the characteristics of an engine. The purpose was to advance the understanding of the stationary turbulence process via computational techniques in the same time. A baseline 4-cylinder 4-stroke CNG engine was chosen. A simultaneous computer simulation was carried out to predict the in-cylinder flow field of the same engine under the same operating condition, using Fluent. The tumble ratio and flow coefficient from both numerical simulation and experimental measurement were compared. A reasonably good level of agreement has been achieved.The steady state approach has its own limitations. It has been shown in the past, high tumble during intake stroke necessarily guarantee high tumble/turbulence at ignition.

Internal Combustion Engine, CFD, Gas Exchange, Intake Port, Flowbench Test, Flow Coefficient, Tumble