Abstract
A better understanding of turbulent premixed flame propagation is the key for improving the efficiency of fuel consumption and reducing the emissions of spark ignition gasoline engines. In this study, we measure turbulent burning velocities (ST) of pre-vaporized iso-octane/air mixtures over wide ranges of the equivalence ratio (φ = 0.9–1.25, Le ≈ 2.94–0.93), the root-mean-square (r.m.s.) turbulent fluctuating velocity (u′ = 0–4.2 m/s), pressure p = 1–5 atm at T = 358 K and p = 0.5–3 atm at T = 373 K, where Le is the effective Lewis number. Results show that at any fixed p, T and u′, Le < 1 flames propagate faster than Le > 1 flames, of which the normalized iso-octane ST/SL data versus u′/SL are very scattering, where SL is the laminar burning velocity. But when the effect of Le is properly considered in some scaling parameters used in previous correlations, these large scattering iso-octane ST/SL data can be collapsed onto single curves by several modified general correlations, regardless of different φ, Le, T, p, and u′, showing self-similar propagation of turbulent spherical flames. The uncertainty analysis of these modified general correlations is also discussed.
Highlights
Designing a better spark ignition (SI) gasoline engine with higher thermal efficiency and lower engine emissions necessitates a thorough understanding of flame kernel initiation and its subsequent flame propagation that take place under high pressure (p), high temperature (T), high r.m.s. turbulent fluctuating velocity (u0 ) and other complex conditions
All mean absolute percentage error (MAPE) percentages for the aforesaid five general correlations are less than 13%, showing that these general correlations are reasonably good
1 and Lewis number (Le) > 1 are measured under elevated pressures and temperatures relevant to SI gasoline engine or micro gas turbine conditions. These measurements reveal the following points: (1) Turbulent burning velocities increase with increasing pressure and temperature at any given
Summary
Designing a better spark ignition (SI) gasoline engine with higher thermal efficiency and lower engine emissions necessitates a thorough understanding of flame kernel initiation and its subsequent flame propagation that take place under high pressure (p), high temperature (T), high r.m.s. turbulent fluctuating velocity (u0 ) and other complex conditions. ST data for liquid fuels (e.g., iso-octane, the major component of gasoline surrogate) under SI engine relevant conditions are rare, since most studies applied gaseous fuels (e.g., methane, propane, hydrogen at atmospheric condition [2,3,4,5,6,7] or at elevated pressure and room temperature conditions [8,9,10,11,12,13,14,15,16]). To the best knowledge of the authors, the only available iso-octane ST data which satisfied high-T, -p and -u0 conditions were that reported by Lawes et al [17] and Nguyen et al [18] using turbulent spherical expanding flame at
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
