The average burning velocities S ¯ b of premixed, spherically expanding iso-octane flames are reported for flame radii from 0.75 to 1.75 cm between 400 and 900 K, near 1 atm. Measurements are performed in lean mixtures (0.9 equivalence ratio) using a helium-enriched oxidizer ( 18 % oxygen, 41 % nitrogen, and 41% helium) to inhibit thermodiffusive instabilities at high temperatures. A shock tube is used to heat the unburned gas to elevated temperatures. Consistently smooth flames with weak S ¯ b temperature dependence are seen between 500 and 580 K. Above 580 K and extending to 740 K, flames exhibit internal structure and surface wrinkling, and a very strong temperature dependence is observed. From 740 to 800 K, a regime of negative S ¯ b temperature dependence is observed. Above 800 K, the measured values of S ¯ b again assume a positive temperature dependence. Although direct numerical simulation studies published in the literature have predicted negative temperature coefficient (NTC) behavior in flames influenced by low-temperature chemistry and cool flames, it is believed that this work represents the first experimental observation of NTC behavior in burning velocity measurements.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Experimental Observation of Negative Temperature Dependence in iso-Octane Burning Velocities


    Contributors:

    Published in:

    AIAA Journal ; 57 , 10 ; 4476-4481


    Publication date :

    2019-09-26


    Size :

    6 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English





    Laminar burning velocities of Iso-Octane-air mixtures - a literature review

    James,E.H. / Univ.of Loughborough,GB | Automotive engineering | 1987



    Numerical and experimental investigation of laminar burning velocities of iso-octane, ethanol and n-butanol

    Beeckmann,J. / Roehl,O. / Peters,N. et al. | Automotive engineering | 2009


    Numerical Investigation of Laminar Burning Velocities of High Octane Fuel Blends Containing Ethanol

    Beeckmann, J. / Peters, N. / Röhl, O. et al. | SAE Technical Papers | 2009