DropletSMOKE++: A comprehensive multiphase CFD framework for the evaporation of multidimensional fuel droplets

Saufi, Abd Essamade; Frassoldati, Alessio; Faravelli, Tiziano; Cuoci, Alberto

doi:10.1016/j.ijheatmasstransfer.2018.11.054

Cited by 28 publications

(44 citation statements)

References 64 publications

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“…2014; Fuster & Popinet 2018; Palmore & Desjardins 2019; Saufi et al. 2019). Previous works were devoted to simulate distillation-like vaporization of light liquids Saufi et al.…”

Section: Introductionmentioning

confidence: 99%

A computational study of thermally induced secondary atomization in multicomponent droplets

et al. 2022

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This study presents computational simulations of multicomponent and multiphase flows to reproduce the physical phenomena in the secondary atomization of a droplet induced by a hot temperature environment. The computational fluid dynamics model is based on the geometric volume of fluid method, with piecewise linear interface calculation reconstruction for accurate determination of the curvature and evaporation fluxes at the interface. The purpose of the model was to faithfully reproduce complex physical processes, such as internal gas cavity formation, liquid–vapour interface instability, cavity collapse and liquid jet ejection, and the pinch-off of a secondary droplet, leading to the microexplosion phenomenon that greatly enhances the evaporation rate of non-volatile liquid droplets. The solver was validated against the analytical solution in benchmark cases, and experimental data with bicomponent droplets reported in the literature. The developed model was used to predict the atomization of heavy fuel oil exposed at high temperatures under microgravity conditions. Different atomization regimes were identified, depending on the initial size of the internal bubbles. While small bubbles led to simple gas ejections, cavity collapse caused the larger bubbles to produce a jet formation. When the ratio between the bubble and droplet volumes was bigger than 0.7, microexplosions occurred. The results were found to be consistent with cases of bubble burst on flat surfaces, showing a strong dependence on the Ohnesorge number ( $Oh$ ). Key observable quantities, particularly jet velocity and bubble cap drainage velocity, were found to agree with correlations reported in other studies. The similarities were also supported by studies extending over a wide range of simulations (4000 cases) at different $Oh$ . An inversion in the dependence of the jet velocity on $Oh$ (above a critical value $Oh_c$ ) was observed.

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“…2014; Fuster & Popinet 2018; Palmore & Desjardins 2019; Saufi et al. 2019). Previous works were devoted to simulate distillation-like vaporization of light liquids Saufi et al.…”

Section: Introductionmentioning

confidence: 99%

A computational study of thermally induced secondary atomization in multicomponent droplets

et al. 2022

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“…Interface properties are calculated from thermodynamic equilibrium using the Raoult law because of the low pressure at stake (at higher-pressure conditions, the use of a cubic EoS might instead be necessary). 37 Flux continuity was finally considered for mass and energy. The resulting set of equations is discretized using an adaptive grid, more refined in proximity of the interface from the liquid side, as well as in the whole flame region in the gas phase.…”

Section: Methodsmentioning

confidence: 99%

Kinetic Modeling of the Ignition of Droplets of Fast Pyrolysis Bio-oil: Effect of Initial Diameter and Fuel Composition

Stagni

Calabria

Frassoldati

et al. 2021

Ind. Eng. Chem. Res.

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Fast biomass pyrolysis is an effective and promising process for high bio-oil yields, and represents one of the front-end technologies to provide alternative, sustainable fuels as a replacement of conventional, fossil-based ones. In this work, the effect of droplet initial diameter on the evaporation and ignition of droplets of crude fast pyrolysis bio-oil (FPBO) and FPBO/ethanol blend (50% vol) at ambient pressure is discussed. The experimental tests were carried out in a closed single droplet combustion chamber equipped with optical accesses, using droplets with a diameter in the range of 0.9–1.4 mm. The collected experimental data show a significant effect of droplet diameter and initial fuel composition on the evaporation and combustion of the droplets. At the same time, 1-dimensional modeling of the evaporation and ignition of different droplets of crude FPBO and its blend with ethanol is performed to understand the complex physical and chemical effects. To this purpose, an 8-component surrogate was adopted, and a skeletal mechanism (170 species and 2659 reactions) was obtained through an established methodology. The comparison of numerical and experimental results shows that the model is able to capture the main features related to the heating phase of the droplet and the effect of fuel composition on droplet temperature and evaporation, particularly the increased reactivity following ethanol addition and the variation of diameter with time. Also, a sensitivity analysis highlighted the reactions controlling the autoignition of the droplets in the different conditions. It was found that the autoignition of pure FPBO droplets is governed by dimethyl furane (DMF), because of its high volatility and in spite of not being the most abundant species. On the other side, ethanol chemistry drives the gas-phase ignition in the case of the blended (50/50 v/v) mixtures, due to its higher volatility and reactivity.

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“…The phase equation is given by Eq. (10), and incorporates diffusion between phase pairs and phase change between the condensed and vaporised chemical species states, for example, between Fe liquid and Fe vapour, and vice versa 48 .…”

Section: Methodsmentioning

confidence: 99%

A thermal fluid dynamics framework applied to multi-component substrates experiencing fusion and vaporisation state transitions

et al. 2020

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The fluid dynamics of multi-component alloy systems subjected to high energy density sources of heat largely determines the local composition, microstructure, and material properties. In this work a multi-component thermal fluid dynamics framework is presented for the prediction of alloy system development due to melting, vaporisation, condensation and solidification phenomena. A volume dilation term is introduced into the continuity equation to account for the density jump between liquid and vapour species, conserving mass through vaporisation and condensation state changes. Mass diffusion, surface tension, the temperature dependence of surface tension, buoyancy terms and latent heat effects are incorporated. The framework is applied to describe binary vapour collapse into a heterogeneous binary liquid, and a high energy density power beam joining application; where a rigorous mathematical description of preferential element evaporation is presented.

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DropletSMOKE++: A comprehensive multiphase CFD framework for the evaporation of multidimensional fuel droplets

Cited by 28 publications

References 64 publications

A computational study of thermally induced secondary atomization in multicomponent droplets

A computational study of thermally induced secondary atomization in multicomponent droplets

Kinetic Modeling of the Ignition of Droplets of Fast Pyrolysis Bio-oil: Effect of Initial Diameter and Fuel Composition

A thermal fluid dynamics framework applied to multi-component substrates experiencing fusion and vaporisation state transitions

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