The objective of the paper is to investigate how the electrodes of a conventional spark plug, including the orientation of the side electrode, influence the flow field around the spark plug.
The problem is that the ignition and early flame propagation process in a spark-ignition engine requires a certain combination of mean velocity and turbulence intensity, and it is therefore of basic importance to know how the spark plug affects these parameters.
Laser Doppler Velocimetry (LDV) measurements have been done at steady-state flow and atmospheric conditions, both inside the spark gap and around the spark plug tip.
Surrounding mean velocity and turbulence intensity have been varied.
The results show a big influence of the spark plug on the mean velocity and turbulence intensity. The side electrode position relative to the mean flow direction is important. The boundary layers on the electrodes are small compared to the spark gap.