Numerical Simulation and Experimental Research on the Free Spray Characteristics of Bio-diesel Fuel

The model of bio-diesel fuel's free spray was founded by using three-dimensional Computational Fluid Dynamics (CFD) software. The distance of fuel jet penetration and sauter mean diameter (SMD) of bio-diesel fuel spray were computed and discussed. The atomization progress of fuel jet was simulated and the pictures of high speed photography were analyzed and compared in detail.

The results showed that the cone angle of bio-diesel fuel was smaller than that of diesel fuel nearly 3 degrees. The high speed photograph of fuel jet along with time was similar to the simulated results. The distance of fuel jet penetration and SMD of bio-diesel fuel was different from that of diesel fuel, and the differences changed along with the time. We found that the main reasons were that the density and viscosity of bio-diesel fuel were greater than that of diesel fuel. The fact will have great effect on the combustion and performance of the engine.