Measurements of engine gas temperature, velocities and early flame propagation

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The sub-project mainly focuses on in-cylinder measurements of fluctuations in time and space, regarding gaseous properties and flame propagation, during the crucial process of ignition. To determine the wall heat flux and the kinetic of auto-ignition, high-resolution images of temperature fluctuations will be mapped within an optical accessible engine, due to laser-induced trace-fluorescence. Additional information of turbulent transport processes will be obtained at the same locations by two-dimensional Particle Image Velocimetry (PIV). Hence with this data, the performed LES results of near wall gaseous properties can be assessed.Further the influence of cyclic variations on the early flame propagation after auto-ignition will be investigated. This is carried out by a special Schlieren-technique with kHz rates of image sequences adapted to the curved geometry of the optical engine. These results are used to qualify the chemiluminescence measurements of sub-project .