Measurement of Flow Velocity in Diesel Flames by a Cross-Correlation Method

A new technique for measuring velocity in diesel flames has been developed: One of the fluctuating components in a flame is detected at infinitesimally separated two points placed along the flow direction, and the time averaged phase difference between two signals is determined from the cross correlation function calculated over a thousand of cycles. Two kinds of correlation method; one focusing on the radiative intensity fluctuation and the other the temperature fluctuation., have been investigated with a D. I. diesel engine at various flow field, and the characteristics of each method have been made clear.