Simulating combustion of a seven-component surrogate for a gasoline/ethanol blend including soot formation and comparison with experiments

FUEL

卷:288

Article

Cuoci, Alberto¹  Avedisian, C. Thomas²  Brunson, Jordan D.²  Guo, Songtao²  Dalili, Alireza²  Wang, Yujie²  Mehl, Marco^1,3  Frassoldati, Alessio¹  Seshadri, Kalyanasundaram⁴  Dec, John E.⁵  Lopez-Pintor, Dario⁵ 

[1] Politecn Milan, Dept Chem Mat & Chem Engn, CRECK Modeling Lab, Piazza Leonardo da Vinci 32, I-20133 Milan, Italy

[2] Cornell Univ, Sibley Sch Mech & Aerosp Engn, Ithaca, NY 14853 USA

[3] Lawrence Livermore Natl Lab, Phys & Life Sci, Livermore, CA 94551 USA

[4] Univ Calif San Diego, Dept Mech & Aerosp Engn, La Jolla, CA 92093 USA

[5] Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA

关键词: Ethanol;    Gasoline;    Numerical analysis;    Droplets;    Surrogates;    Soot formation;    Combustion;   

DOI  :  10.1016/j.fuel.2020.119451

来源: Elsevier

【 摘 要 】

Combustion of a seven-component surrogate for a research grade 87 octane gasoline mixed with 10% ethanol is investigated experimentally and numerically from the perspective of an isolated droplet burning under conditions that promote one-dimensional gas transport. The numerical analysis included a kinetic mechanism comprised of 398 species and 24,814 reactions and a soot model that accounted for nucleation, surface growth, coalescence/aggregation of soot particles, and luminous flame radiation. Measurements of droplet and flame diameters were made for an initial droplet diameter (D-o) of approximately 0.63 mm. The simulations agreed well with the measurements including the location of the soot shell. Preferential vaporization was revealed by simulations of the liquid concentrations in the droplet. Predicted peak soot volume fractions coincided with temperatures between 1300 K and 1400 K as a soot inception temperature. Simulations were also carried out for D-o between 0.25 mm and 5 mm to explore the effect of radiation and D-o on burning. Below 0.25 mm radiation was negligible and burning rates and flame temperatures converged to a single value. Increasing D-o up to 1.8 mm lowered the burning rate with luminous radiation having a strong effect. When radiation was entirely removed from the model the burning rate was nearly constant. Above D-o = 2 mm droplets extinguished almost immediately after ignition. The flame temperature decreased with increasing D-o while it increased when radiation was omitted. The simulations show that soot precursors including polyammatic hydrocarbons were concentrated around the soot shell.

【 授权许可】

Free