Effects of injector tip design on the spray characteristics of soy methyl ester biodiesel in a blurry injector

Atomization plays an important role in combustion and propulsion systems, including applications in transportation and power generation. The uncertainties in oil supply and environmental concerns motivate the development of new combustion technologies using biofuels, capable of operating with high thermal efficiency, low operational cost and reduced environmental impact. Flameless combustion is a promising technology that allows the reduction of pollutant emissions with high combustion efficiency. This work describes the characteristics of soy methyl ester (SME) sprays produced by a blurry injector. Characteristics droplet diameters, discharge coefficients, air-to-liquid mass ratios, air and liquid pressures and spray cone angles were experimentally determined. Three nozzle tip configurations have been tested: cylindrical, conical and conical-cylindrical. All nozzles configurations have presented high atomization efficiency, yielding relatively small characteristics diameters (SMD and MMD) and narrow spray cone angles, favoring its application in compact combustion systems.