ディーゼル噴霧の粒径に及ぼす燃料粘度の影響

抄録

To study the effect of fuel viscosity, injection pressure and surface tension on the mean droplet size and spray angle, the diesel fuel spray droplets were measured by a Laser diffraction technique. Several kinds of glycerine solution with water and residual fuel oil were used. The tests were carried out over a wide range of injection pressure [3 to 90 MPa (30.6 to 917.7 kgf/cm²) ] and of kinematic viscosity of liquid [1×10^-6 to 200×10^-6 m² /s (1 to 200 cSt) ] at ambient pressure of 3 MPa (30.6 kgf/cm²) .
The main results obtained are as follows:
(1) Sauter mean diameter increases with increasing kinematic viscosity of liquid, but decreases with increasing injection pressure. There are an upper limit of viscosity and a lower limit of the pressure to produce a fine spray.
(2) At high injection pressure, the effect of viscosity on Sauter mean diameter still remains, but the viscosity has no effect on the spray angle.
(3) When the viscosity is the same at low injection pressure, Sauter mean diameter of glycerine solution spray is larger than that of residual oil. Surface tension has no effect on the Sauter mean diameter at high injection pressure.