Steady flow and dynamic analyses comparison of an air intake breathing capacity

Abstract

Analysis of intake breathing capacity is important in order to determine the performance output for any respective engine. Flow coefficient and discharge coefficient are the common parameters used to define the breathing capability and different analysis have been applied by researchers to determine these parameters which include experiments and Computational Fluid Dynamics (CFD) analyses. This study aims to investigate the difference in breathing parameters obtained from steady flow simulation and dynamics simulation. Proton CAMPRO 1.6-litre engine was selected as the reference engine in this study. The experiment involved was the flow bench test, while CFD simulation carried out were the port flow analysis (steady flow) and the cold flow analysis (dynamics). Results obtained indicate that flow coefficient and discharge coefficient from cold flow simulation are always lower than both parameter values obtained from port flow simulation and experiment with large deviations of minimum 15.6% and maximum 27%. Meanwhile, the breathing parameter values from port flow simulation were very close to the experimental data with the minimum deviation of 1.6%. This study concludes that port flow simulation is very accurate for the analysis of defining intake breathing capacity, meanwhile cold flow simulation can be used to predict the trend and lower limit of these parameters especially at low valve lift.