Evaporation characteristics of acetone–butanol–ethanol and diesel blends droplets at high ambient temperatures

Abstract This paper, dedicated to Norbert Peters, follows his lead in developing theoretical understanding of the complex flow-turbulence interactions occurring in the propagation of premixed flames. The work is based on the asymptotic hydrodynamic model of premixed flames, where the flame is modeled by a surface that separates unburned and burned gases and propagates relative to the incoming flow at a speed that depends locally on the flame stretch rate. As such the work may be categorized as corresponding to the “flamelet regime”, based on the turbulent combustion regimes diagram. The results at the present are limited to mixtures corresponding to positive Markstein lengths, and to “two-dimensional turbulent flows”. In this parametric study, the different factors affecting the turbulent flame speed have been examined and scaling laws for the turbulent flame speed are proposed for low-to-moderate turbulence intensities that highlight the dependence on physically measurable quantities. Comparison to various empirical correlations suggested in the literature is presented. The results, devoid of turbulence-modeling assumptions and/or ad-hoc coefficients, can help explaining the influence of varying the system parameters individually and collectively, and formulating physically-based small-scale models for large-scale numerical simulations of turbulent flames.

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The turbulent flame speed for low-to-moderate turbulence intensities

https://iopscience.iop.org/article/10.1088/1873-7005/aab510/pdf

The Darrieus–Landau instability of premixed flames

Environmental aspects of converting municipal solid waste into energy as part of composite fuels

Combustion characteristics of diesel and Jet-A droplets blended with polymeric additive

Effects of gellant concentration on the burning and flame structure of organic gel propellant droplets

Effects of initial droplet diameter and pressure on burning of ATF gel propellant droplets

Nonlinear development of hydrodynamically-unstable flames in three-dimensional laminar flows

Electric field effects in the presence of chemi-ionization on droplet burning

The morphological development of wrinkles along the surface of a Bunsen flame in a weakly-turbulent flow is investigated, with turbulence added solely to disturb the flame front. The resulting flame-flow interactions are examined using a hybrid Navier–Stokes/front-tracking methodology within the context of the hydrodynamic theory. Topological markers based on the skewness of curvature are introduced to distinguish between sub- and super-critical conditions, or the absence/presence of the Darrieus–Landau instability, respectively. We show that for sub-critical conditions disturbances created along the flame surface are dampened when convected downstream along the flame front, and the flame surface is only weakly perturbed. For super-critical conditions, on the other hand, disturbances of the flame front are amplified when advected downstream leading to a highly corrugated surface and a flame brush of increasing thickness. A measure of these dramatic changes is included in the mean local stretch rate which, when properly modulated by a Markstein length, directly affects the turbulent flame speed.

Advitya Patyal

Papers

Effects of gellant concentration on the burning and flame structure of organic gel propellant droplets

Effects of initial droplet diameter and pressure on burning of ATF gel propellant droplets

Nonlinear development of hydrodynamically-unstable flames in three-dimensional laminar flows

Electric field effects in the presence of chemi-ionization on droplet burning

Morphology of wrinkles along the surface of turbulent Bunsen flames – Their amplification and advection due to the Darrieus–Landau instability