Impact of alternative and fossil diesel fuels on internal flow of injection nozzle

Abstract

This work presents a computational study about the effect of different fossil fuels (Diesel and GTL) and renewable (Farnesane and Biodiesel) on the characteristics of the nozzle fuel internal flow (speed flow, cavitation, mass flow rate and discharge coefficient). This investigation was focused on the pass of fuel from the volume around the tip of the injector needle to the nozzle holes. Several engine-operating conditions, characteristic of urban driving conditions, were tested. These conditions, characterized by their injection pressure and injection timing as well as the experimental rates of fuel injected, were simulated with all mentioned fuels. Solenoid operated seven holes injector, 0.15 mm orifice diameter was used. Results show the effect of fuel origin on the internal flow along the nozzle orifice of the injector. Among the results obtained are the following: at medium load the effect of the needle lift on the cavitation generation is more significant than the fluid circulation velocity and fuel origin impacts as follows: Biodiesel > GTL > Farnesane > Diesel; while, at medium or high engine speed, an increase of engine load causes a decrease of cavitation generation and fuel origin impacts as follows: Diesel >> Farnesane > GTL > Biodiesel.