Experimental investigation on GDI spray behavior of isooctane and alcohols at elevated pressure and temperature conditions

In this study macroscopic spray characteristics and droplet size distribution were measured for spray emanating from a six-hole solenoid GDI fuel injector. Three test fuels namely Isooctane, ethanol and n-butanol were used in this study. Macroscopic spray characterization was performed using Mie scattering and Schlieren Shadowgraph technique along with high speed videography. Liquid and vapor penetration length and along with the liquid/vapor spray cone angle was determined using these techniques. Phase Doppler Particle Analyzer (PDPA) was used to determine droplet size distribution. Results showed that thermo-physical properties such as saturation temperature, latent heat of vaporization, surface tension, density and viscosity of a fuel play a very important role in the spray plume penetration. Isooctane showed the least penetration lengths for all pressure and temperature conditions that were evaluated in this study, whereas butanol showed the highest penetration length. Due to the higher values surface tension, viscosity and latent heat of evaporation, alcohol sprays consisted of droplets of larger diameter.