This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Superheated Sprays of Alternative Fuels for Direct Injection Engines
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 16, 2012 by SAE International in United States
Annotation ability available
Alternative and oxygenated fuels are nowadays being studied in order to increase engine efficiency and reduce exhaust emissions and also to limit the automotive industry's economical dependency from crude oil. These fuels are considered more ecological compared to hydrocarbons because they are obtained using renewable sources. Fuels like anhydrous/hydrous ethanol, methanol or alcohol/gasoline blends which are injected in liquid form must vaporize quickly, especially in direct injection engines, therefore their volatility is a very important factor and strongly depends on thermodynamic conditions and chemical properties. When a multi-component fuel blend is injected into a low pressure environment below its saturation pressure, a rapid boiling of the most volatile component triggers a thermodynamic atomization mechanism. These kinds of sprays show smaller droplets and lower penetration compared to mechanical break up. The prediction of vapor liquid equilibrium is very important when different components are blended to form a fuel, especially dealing with flash boiling applications and non ideal mixtures like alcohol/hydrocarbons.
This work presents a combined 1D/3D numerical modeling of fuel injection processes under superheated conditions involving different single and multi-component hydrocarbons and alternative fuels for automotive applications, such as ethanol, methanol and alcohol/gasoline blends. Primary break up through multi-hole injectors is affected by phase change within the nozzle of the fuel blend due to flash boiling. Particular attention must be given to the thermo-physics description of the fuel properties, since the vaporization process is a key in liquid fuel injections and mixture formation.
The vapor pressures of the partial components are calculated using the Peng-Robinson equation of state and the non ideal phase equilibrium of alcohol/hydrocarbon mixtures is modeled using activity coefficients. An Homogeneous Relaxation Model (HRM) is adopted to model the thermodynamic instability of the fuel within a 1D nozzle flow model. 1D simulation results, such as droplet size distribution, are used to define initial conditions for 3D Lagrangian spray simulations performed by using a specific evaporation model, designed to reproduce the vaporization rate from superheated droplets.
CitationNegro, S., Brusiani, F., and Bianchi, G., "Superheated Sprays of Alternative Fuels for Direct Injection Engines," SAE Technical Paper 2012-01-1261, 2012, https://doi.org/10.4271/2012-01-1261.
- Wagner, T., Gray, D., Zarah, B., and Kozinski, A., “Practicality of Alcohols as Motor Fuel,” SAE Technical Paper 790429, 1979, doi: 10.4271/790429.
- Hsieh, W.D., Chen, R.H., Wu, T.L., Lin, T.H., “Engine performance and pollutant emission of an SI engine using ethanol-gasoline blended fuels”, Atmospheric Environment 36 (2002) 403-410.
- Mielenz, J.R., “Ethanol production from biomass: technology and commercialization status”, Current Opinion in Microbiology 4 (2001) 324-9.
- Al-Hasan, M., “Effect of ethanol-unleaded gasoline blends on engine performance and exhaust emissions”, Energy Conversion and Management 44 (2003) 1547-1561
- Thring, R., “Alternative Fuels for Spark-Ignition Engines,” SAE Technical Paper 831685, 1983, doi: 10.4271/831685.
- Bayraktar, H., “Experimental and theoretical investigation of using ethanol-gasoline blends in spark-ignition engine”, Renewable Energy 30 (2005) 1733-1747.
- Senda, J., Hojyo, Y., and Fujimoto, H., “Modelling of Atomization Process in Flash Boiling Spray,” SAE Technical Paper 941925, 1994, doi: 10.4271/941925.
- Kim, YK, Twai, N, Suto, H, Tsuruga, T., “Improvement of alcohol engine performance by flashing injection”, JSAE Review 2 (1980) 81-6.
- Zuo, B., Gomes, A.M., and Rutland, C.J., “Modeling Superheated Fuel Sprays and Vaporization”, Int. J. Engine Research, vol. 1, no. 4, pp. 321-336.
- Adachi, M., McDonell, V., Tanaka, D., Senda, J. et al., “Characterization of Fuel Vapor Concentration Inside a Flash Boiling Spray,” SAE Technical Paper 970871, 1997, doi: 10.4271/970871.
- VanDerWege, B., Lounsberry, T., and Hochgreb, S., “Numerical Modeling of Fuel Sprays in DISI Engines Under Early-Injection Operating Conditions,” SAE Technical Paper 2000-01-0273, 2000, doi:10.4271/2000-01-0273.
- Myong, K.-J., Arai, M., Tanaka, T., Senda, J., Fujimoto, H., “An Experimental Investigation and Numerical Analysis of Multi-Component Fuel Spray”, JSME International Journal Series B, 47 (2) (2005) 200-206.
- Kawano, D., Ishii, H., Suzuky, H., Goto, Y., Odaka, M., Senda, J., “Numerical Study on Flash-Boiling of Multicomponent Fuel”, Heat Transfer-Asian Research, 35 (5) (2006) 369-385.
- Neroorkar, K., Schmidt, D., “Modeling of vapor-liquid equilibrium of gasoline-ethanol blended fuels for flash boiling simulations”, Fuel 90 (2011) 665-673
- Neroorkar, K. and Schmidt, D., “A Computational Investigation of Flash-Boiling Multi-hole Injectors with Gasoline-Ethanol Blends,” SAE Technical Paper 2011-01-0384, 2011, doi:10.4271/2011-01-0384.
- Negro, S., Brusiani, F., and Bianchi, G., “A Numerical Model for Flash Boiling of Gasoline-Ethanol Blends in Fuel Injector Nozzles,” SAE Int. J. Fuels Lubr. 4(2):237-256, 2011, doi:10.4271/2011-24-0003.
- Peng, D. Y., Robinson, D. B., “A New Two-Constant Equation of State”, Ind. Eng. Chem., Fundam., 15 (1) (1976) 59-64
- Solorzano-Zavala, M., Barragan-Aroche, F., Bazua, E.R., “Comparative study of mixing rules for cubic equations of state in the prediction of multicomponent vapor-liquid equilibria”, Fluid Phase Equilibria 122 (1996) 99-116.
- Pumphrey, J.A., Brand, J.I., Scheller, W.A., “Vapor pressure measurements and predictions for alcohol-gasoline blends”, Fuel 79 (2000) 1405-1411.
- Gmehling, J., Onken, U., “Vapor-Liquid Equilibrium Data Collection: DECHEMA Data Series”, DECHEMA, Frankfurt, 1977.
- Negro, S., Bianchi, G.M., “Superheated fuel injection modeling: an engineering approach”, International Journal of Thermal Sciences 50 (2011) 1460-1471.
- Downar-Zapolski, P., Bilicki, Z., “The Non-Equilibrium Relaxation Model for One-Dimensional Flashing Liquid Flow”, Int. J. Multiphase Flow, vol. 3, 22, pp. 473-483, 1996.
- Bianchi, G., Forte, C., Negro, S., and Pelloni, P., “A 1d Model for the Prediction of Flash Atomization in Gdi Multi-Hole Injectors: Preliminary Results,” SAE Int. J. Engines 1(1):1278-1293, 2009, doi:10.4271/2008-01-2516.
- Schmehl, R., Steelant, J., “Flash-Evaporation of Oxidizer During Start-Up of an Upper-Stage Rocket Engine”, AIAA Paper 2003-5075, 39th AIAA/ASME SAE/ASEE Joint Propulsion Conference and Exhibit, Huntsville, Alabama, July 20-23 2003.
- Frossling, N., “On the Evaporation of Falling Droplets”, Gerlands Beitr.Geophys., 52 (1938) 170-216.
- Lefebvre, A., “Atomization and Sprays”, Hemisphere Pub. Corp., New York, 1989.
- Raju, M.S., “CFD Modeling of Superheated Fuel Sprays”, NASA/CR-2008-215289, AIAA 2009-1187, 47th Aerospace Sciences Meeting, Orlando, Florida, January 5-8, 2009.
- Hull, A., Kronberg, B., van Stam, J., Golubkov, I., Kristensson, J., “Vapor-Liquid Equilibrium of Binary Mixtures. 1. Ethanol + 1-Butanol, Ethanol + Octane, 1-Butanol + Octane”, J. Chem. Eng. Data 2006, 51, 1996-2001.
- Chemical Engineering Research Information Center, web database http://www.cheric.org/kdb, 1995-2011 CHERIC, Seul, Korea.
- Fire v2010 Workflow Manager Users Guide, AVL List GmbH, Graz, Austria, 2010.
- Reitz, R., D., “Mechanisms of Atomization Processes in High-Pressure Vaporizing Sprays”, Atomization and Spray Technology, 3 (1987) 309-337.
- Gao, J., Jiang, D., Huang, Z., “Spray properties of alternative fuels: A comparative analysis of ethanol-gasoline blends and gasoline”, Fuel 86 (2007) 1645-1650.