American Association for Aerosol Research - Abstract Submission

AAAR 39th Annual Conference
October 18 - October 22, 2021

Virtual Conference

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Santoro Flame: The Volume Fraction of Soot Accounting for Its Morphology & Composition

GEORGIOS A. KELESIDIS, Sotiris Pratsinis, ETH Zurich, Switzerland

     Abstract Number: 53
     Working Group: Carbonaceous Aerosol

Abstract
Laser diagnostics for on-line monitoring of soot mass or volume fraction, fv, from combustion sources are calibrated using co-flow diffusion flames, such as the miniCAST generator [1]. In this regard, the soot fv measured by Santoro and coworkers [2] in an ethylene diffusion flame by light extinction is used widely to validate soot formation and growth models. This fv has been obtained using constant absorption function, E(RI) = 0.16 or 0.19, for soot spheres neglecting the evolving soot morphology and composition. The fv obtained that way is 2 times larger than that measured by thermocouple particle densitometry (TPD) [3] at identical conditions.

Here, the evolution of fv in the above flame is derived accounting for the realistic soot morphology and composition [4] by coupling discrete dipole approximation [5] with discrete element modeling for soot surface growth and agglomeration [6]. The soot fv derived using light extinction data with this variable E(RI) accounts for the realistic soot morphology and composition, in excellent agreement with TPD data [3] at the centerline and maximum fv path of the Santoro diffusion flame. So, the evolving soot morphology and composition are essential to determine the soot fv and close the mass balance of models for soot formation and growth.

References:
[1] Maricq, M.M. (2014). Aerosol Sci. Technol., 48, 620-629.
[2] Puri, R., Richardson, T.F., Santoro, R.J. and Dobbins, R.A. (1993). Combust. Flame, 92, 320-333.
[3] McEnally, C.S., Koylu, U.O., Pfefferle, L.D. and Rosner, D.E. (1997). Combust. Flame, 109, 701-720.
[4] Kelesidis, G.A. and Pratsinis, S.E. (2021). Proc. Combust. Inst., 38, 1189-1196.
[5] Kelesidis, G.A. and Pratsinis, S.E. (2019). Proc. Combust. Inst., 37, 1177-1184.
[6] Kelesidis, G.A., Goudeli, E. and Pratsinis, S.E. (2017). Carbon, 127, 527-535.