MEASUREMENT OF THE FLOW-FIELD IN A DIESEL-ENGINE COMBUSTION-CHAMBER AFTER COMBUSTION BY CROSS-CORRELATION OF HIGH-SPEED PHOTOGRAPHS

A cellular cross-correlation technique is applied to high-speed photog raphs of the luminous phase of combustion in a high-speed direct-injec tion diesel engine. The method enables the velocity and vorticity dist ributions in the combustion chamber to be evaluated. The results obtai ned from the basic technique are refined to remove spurious results an d to complete the definition of the flow field by applying data valida tion, interpolation, and smoothing. The velocity and vorticity fields evaluated at two swirl ratios show the way in which the basically soli d body swirl motion interacts with the fuel jets in the combustion cha mber. A better understanding of the post-combustion fluid motion is ob tained, and this should be of help in validating CFD codes and also th e design of engines.