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Gas Versus Spray Injection: Which Mixes Faster?
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English
Abstract
Results are presented of 3-D computations of direct injection of gaseous methane and of liquid tetradecane through a multi-hole injector into a Diesel engine. The study focusses on the distribution of fuel/air ratio within the resulting gas and spray jets under typical Diesel conditions prior to ignition. It is shown that for a significant time after start of injection, the fraction of the vapor fuel which is in richer-than-flammable mixtures is greater in gas jets than in sprays. For methane injection, it is also shown that changing some of the flow conditions in the engine or going to a poppet-type injector, does not result in improved mixing. An explanation of these results is provided also through an analysis of the self-similar gas jet and 2-D computations of gas and spray jets into constant pressure gas. A scaling for time and axial distance in the self-similar gas jet also clarifies the results. In all, it is concluded that in general a spray mixes faster than a gas jet in direct-injection Diesel engines.
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Abraham, J., Magi, V., MacInnes, J., and Bracco, F., "Gas Versus Spray Injection: Which Mixes Faster?," SAE Technical Paper 940895, 1994, https://doi.org/10.4271/940895.Also In
References
- Beck, N.J. “Natural Gas - A Rational Approach to Clean Air,” SAE Paper 902228 1990
- Liss, W. Thrasher, W. “Natural Gas as a Stationary Engine and Vehicular Fuel,” SAE Paper 912364 1991
- Nylund, N.-O. Riikonen, A. “Low-Polluting Gas Fueled Heavy-Duty Vehicles,” SAE Paper 912365 SAE Trans. 100 1991
- Pai, S.-I. Fluid Dynamics of Jets D. Van Nostrand Co., Inc. New York 1954
- Abramovich, G.N. The Theory of Turbulent Jets The M.I.T. Press Cambridge, MA 1963
- Schlichting, H. Boundary Layer Theory McGraw-Hill Book Co. N.Y. 1968
- Wygnanski, I. Fiedler, H. “Some Measurements in the Self-Preserving Jet,” J. Fluid Mech. 38 577 612 1969
- Rajaratnam, N. Turbulent Jets Elsevier Scientific Publishing Co. Amsterdam 1976
- Bracco, F.V. “Modeling of Engine Sprays,” SAE Paper 850394 SAE Trans. 94 SAE Publication No. P-156 “Engine Combustion Analysis: New Approaches,” 1985
- Reitz, R.D. Diwaker, R. “Structure of High-Pressure Fuel Sprays,” SAE Paper 870598 SAE Trans. 96 1987
- Reitz, R.D. “Modeling Atomization Processes in High-Pressure Vaporizing Sprays,” Atomization and Spray Technology 3 309 337 1987
- Abraham, J. Bracco, F.V. “Fuel-Air Mixing and Distribution in a Direct-Injection Stratified-Charge Rotary Engine,” SAE Paper No. 890329 SAE Trans. 98 1989
- Abraham, J. Bracco, F.V. “3-D Computations to Improve Combustion in a Stratified-Charge Rotary Engine - Part II: A Better Spray Pattern for the Pilot Injector,” SAE Paper No. 892057 , SAE Trans. 98 1989
- Abraham, J. Bracco, F.V. “3-D Computations to Improve Combustion in a Stratified-Charge Rotary Engine - Part III: Improved Ignition Strategies,” SAE Paper No. 920304 , SAE Trans. 101 1992
- Abraham, J. Epstein, P. Bracco, F.V. “3-D Computations to Improve Combustion in a Stratified-Charge Rotary Engine - Part IV: Modified Rotor Pockets,” SAE Paper No. 930679
- Abraham, J. Bracco, F.V. “Combustion Optimization Computations - Part I: Swirl and Squish Effects in Air-Assist Injection Engines,” SAE Paper No. 922240 , SAE Trans. 101 1992
- Magi, V. “REC-87: A New 3-D Code for Flows, Sprays and Combustion in Reciprocating and Rotary Engines,” MAE Report No.1793 Princeton University 1987
- Grasso, F. Wey, M.-J. Abraham, J. Bracco, F.V. “Three-Dimensional Computations of Flows in a Stratified-Charge Rotary Engine,” SAE Paper No. 870409 , SAE Trans. 96 1987
- MacInnes, J.M. Bracco, F.V. “Computation of the Spray from an Air-Assisted Fuel Injector,” SAE Paper No. 902079
- Abraham, J. Bracco, F.V. “Effects of Combustion on Mixing in Gas-Injected Diesel Engines,”