Numerical Analysis on the Effect of Aspect Ratio in a Diesel Injector Using Diesel and Diesel–Ethanol Blend

In direct injection diesel engines, spray optimization greatly enhances efficiency and low emissions combustion. The flow inside an injector impacts the process of spray, combustion, and exhaust. The nozzle shape and spray determine the atomization and the outlet engine emissions. The results were obtained for spray characteristics of diesel and ethanol–diesel blend in a nozzle injector with aspect ratios varying from 1, 1.2, 1.4, and 1.6. Parameters, such as spray penetration length, spray angle, and spray characteristics including the Sauter mean diameter (SMD), the De Brouckere diameter, the mean diameter and volume, and particle velocity, were investigated and revealed a strong dependence on modifications in the aspect ratio of the nozzle orifice. Simulation of atomization model was carried out and compared using discrete phase model (DPM) using computational fluid dynamics (CFD) modeling. Additionally, validation from the experiment finding results is also provided. Elliptical C was observed to have a minimum SMD up to 28.04% and a minimum De Brouckere diameter up to 28.63%. Ethanol–diesel blend showed best spray parameters when considering the macroscopic spray properties and the drop size distribution. Moreover, under non-evaporative conditions, the tested fuel ethanol–diesel Blend exhibited better spray characteristics and better cavitation phenomenon of 12.13% at higher aspect ratios than at lower ones. In addition, elliptical nozzle spray had a higher spray cone angle than circular nozzle spray.