TWO COMPONENT VELOCITY AND SIZE MEASUREMENTS FOR A NON-COMBUSTING FUEL SPRAY IN A DIESEL SWIRL COMBUSTION CHAMBER

An analysis of the atomization of a non-combusting alcohol spray produced by a Diesel injector with a single hole nozzle injecting radially, from a central location, into a cylindrical swirl chamber of a research Diesel engine is reported. A two component laser/phase Doppler anemometer system, LDA/PDA, has been used to measure simultaneously 2 orthogonal velocity components and the size of the individual droplets in the spray, as a function of time, as they were transported away from the spray by the swilling air motion. The measurements were performed in the central plane of the cylindrical swirl chamber but were restricted, by the optical access to the quadrant downstream from the radial spray trajectory. The data has been reduced to form an animation indicating the spatial distribution of the droplets, their mean velocities, trajectories and sizes as a function of time. The data show that the spray tip and tail atomize more effectively than the main body of the spray. The result is that droplets can only be found in the inner region of the combustion chamber at the start and end of injection.