Experimental Investigation of the Influence of Fuel Viscosity on the Spray Characteristics of Diesel Nozzle

This paper presented an investigation of atomization characteristics including the velocity vector field and the mean droplet sizes for different percentages of DMM-diesel blended fuels using a phase doppler anemometry (PDA) analyzer system. Based on the fuel design concept, an oxygenated fuel named dimethoxy methane (DMM),which has lower viscosity, surface tension, and boiling point, was used to blend with diesel. The experiments were carried out under atmospheric conditions on a single-hole type diesel nozzle, liquid conditions comprise a temperature of 298 K under the needle valve opening pressure of 6 MPa. The results show that the sauter mean diameter (SMD) and spray cone angle of blended fuels decrease with the increase of DMM content; the axial mean velocity in the centerline increases with the increase of DMM. However, the spray behavior of blended fuel in which DMM exceeds 75% is virtually identical to that of neat DMM. The measurement also reveals the existence of an "S" shape in the radial mean velocity variations with radial distance.