Alternative Fuel Spray Length Characterization: Comparing Diesel and Biodiesel Fuels Thomas McGuire EGEE 520 Section 001

Presentation Outline Introduction and Previous Research Governing Equations Solution of Fuel Velocity Distribution Solution of Fuel Concentration Distribution Conclusions Resources

Introduction and Previous Research Use of Diesel Particulate Filters (DPFs) since 2007 have necessitated the use of post-injection Current theory states that increased viscosity and density of biodiesel over petroleum diesel leads to longer spray length [1, 2] Longer spray penetration leads to observed increased engine oil dillution

Introduction and Previous Research DieselBiodiesel Specific Gravity Viscosity (cSt) Vapor Pressure at 300K (mmHg) The specific gravity, viscosity and vapor pressure of petroleum and biodiesel are shown in table 1 Properties of the fuel were input along with a 0.5mm injector nozzle diameter and 200 MPa pressure difference to simulate modern diesel injection [5, 6] Table 1: Comparison of Fuel Properties [1-4]

Characteristic Equations Navier-stoke’s equation for fluid flow simulation Fick’s law for diffusion simulation Due to Reynolds number and Peclet number limitations of COMSOL the pressure difference over the injector had to be limited to 1kPa

Solution Diesel Velocity Distribution Biodiesel Velocity Distribution

Solution Pure Diffusion without Advection

Solution Diesel Fuel Distribution Biodiesel Fuel Distribution

Conclusions During the parametric study both higher viscosity and higher density slow and shorten the fuel spray in our simulations With both higher density and viscosity, simulations showed results contrary to theories on diesel engine oil dilution problems with biodiesel The main reason for the findings from our study are due to the inability to accurately simulate high pressure turbulent flow consistent with real-world diesel fuel injection

Resources 1.Graboski, Michael S. and Robert L. McCormick. “Combustion of Fat and Vegetable Oil Derived Fuels in Diesel Engines.” Progress in Energy and Combustion Science. 24 (1998) He, Chao, Yunshan Ge, Jianwei Tan and Xiukun Han. “Spray Properties of Alternative Fuels: A comparative analysis of biodiesel and diesel.” International Journal of Energy Research. 32 (2008) Yuan, W.,.C. Hansen, and Q. Zhang. “Vapor Pressure and Normal Boiling Point Predictions for Pure Methyl Esters and Biodiesel Fuels.” Fuel. 84 (2005) MSDS Summary Sheet. No. 2 Diesel Fuel. (2002) MSDS Summary Sheet. Biodiesel Fuel Ejim, C.E., B.A. Fleck, and A. Amirfazli. “Analytical study for atomization of biodiesels and their blends in a typical injector: Surface tension and viscosity effects.” Fuel. 86 (2007)