Using a computer aided design(CAD) model developed for the port valve cylinder of a single helical port diesel engine

a visual port steady flow test of the oil flow method and a swirl ratio measurement of different cross sections were carried out. At the same time

the CAD model was imported into a computational fluid dynamics(CFD) software to cross validate the numerical simulation using these experimental results

and the changes of in cylinder near wall flow field and the swirl ratio of different cross sections were analyzed. Results show that the formula of methyl silicone oil

oleic acid and aluminum power with a mass ratio of 8:8:3 can provide a very clear and complete information for the in cylinder near wall flow field. As observed

at the cylinder wall closest to the cylinder inlet

there is a high speed airflow area that expands with the increase of valve opening

promoting the thinning of oil film on the cylinder wall

which poses a great risk to the safe operation of cylinder and piston. Moreover

during the intake process

the in cylinder swirl ratio strengthens as the valve opening increases

and gradually decreases as the measurement position moves away from the cylinder head.