Investigation of the in-cylinder swirl flow measurement methods and comparison between them in a cylinder head

In the design of the intake port of an internal combustion engine, investigation of the flow coefficient and the swirl ratio is important, simultaneously. They are effective on the volumetric efficiency and combustion efficiency, respectively. Steady flow testing of cylinder heads is one of the methods to measure the flow coefficient and the swirl ratio. In this study, at first, two different methods of swirl measurement are introduced and governing equations is presented. In the following, experimental tests with both methods are performed on the cylinder head and the results of them are investigated. Swirl measurement consist measurement of the rotational speed of paddle wheel or the torque is applied to a honeycomb to take into account the swirl ratio. The paddle wheel mechanism gives lower measured swirl ratio.