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An experimental study on the interaction of sprays from clustered orifices is presented. Droplet size and velocity information has been gained by means of Phase Doppler Anemometry for different nozzle configurations varying the diverging opening angle between clustered sprays from 0° to 15°. These nozzles were investigated under high-pressure (50 bar) and high-temperature (800 K) conditions in a pressure chamber and the results are compared to two standard nozzles with flow rates corresponding either to the flow rate of the cluster nozzle configuration or half of the flow rate of this configuration. Two injection pressures, 600 bar and 1100 bar, were used to investigate all nozzles. This investigation completes the characterization of sprays from the cluster nozzles presented in an earlier work. Findings obtained therein were used to choose the measurement procedure for the present investigation and also to determine the spray width in order to obtain the spray angle.

Targeted fuel blending is a known method to improve the performance of an automotive engine. Two candidates for a biofuel blend are the linear C8H18O isomers 1-octanol and di-n-butyl ether (DNBE). Both fuels feature an increased amount of oxygen that reduces soot emissions. However, physical properties of both fuels differ significantly and thus, a different type of spray mixing and combustion is expected: The low reactivity of 1-octanol causes a long ignition delay enabling a better mixture homogenization, but also causes HC and CO emissions. DNBE in contrary is highly volatile, has a short ignition time and thus can act as an ignition booster for 1-octanol without losing positive effects concerning emissions. In this work a spray study is performed for blends of 1-octanol and DNBE. Measurements are conducted under diesel-like engine conditions with an 8-hole piezo injector. High-speed Schlieren and Mie scattering techniques are used for spray visualizations.