Measurement of Velocity and Turbulence Scale Near the Spark Plug by Using a Two-Color PIV Method

It has been known that the in-cylinder flow field structure at the time of ignition timing has an effect on the shape and propagating speed of initial flame. Particle image velocimetry (PIV), a planar measuring technique, is a very efficient tool for studying complicated flow fields such as in-cylinder flow and intake port flow, and relies on fast and efficient method to track numerous particles suspended in the flow. In this study, two-color scanning PIV is designed to measure the two-dimensional velocity data by using a rotating mirror and a beam splitter. This PIV method gives the information about the complex turbulent flow and vorticity including tumbling flow by using a spatial filtering technique. From this experimentation, we obtained the few-mm turbulent integral length scales with a high spatial resolution and showed that the mean velocity and the turbulence strength increased linearly with the increase of engine speed.