Large eddy simulations of nanoparticle synthesis from flame spray pyrolysis

Rittler, Andreas; Deng, Lei; Wlokas, Irenäus; Kempf, Andreas

doi:10.1016/j.proci.2016.08.005

Cited by 56 publications

(32 citation statements)

References 49 publications

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“…Concerning alternative reconstruction techniques to obtain time-averaged PSD, Rittler et al [34] suggested to use temporal fluctuations of s from a monodisperse model. This strategy was applied to the investigation of the titanium oxide population in a turbulent flame.…”

Section: Analysis Of Resultsmentioning

confidence: 99%

“…In conclusion, the 3-eq model provides good prediction of soot global quantities with no fitting procedure for parameters governing soot production processes. Figure 9: Time-averaged R-PSD with the 3-eq model (continuous black line) is compared to temporal fluctuations of the mean particle volume (histogram, [34]) for the data presented in Fig. 8.…”

Section: Analysis Of Resultsmentioning

confidence: 99%

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A three-equation model for the prediction of soot emissions in LES of gas turbines

Franzelli

Vié

Darabiha

2019

Proceedings of the Combustion Institute

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The design of new low-emission systems requires the development of models providing an accurate prediction of soot production for a small computational cost. In this work, a three-equation model is developed based on mono-disperse closure of the source terms from a sectional method. In addition, a post-processing technique to estimate the particles size distribution (PSD) from global quantities is proposed by combining Pareto and log-normal distributions. After validation, the developed strategy is used to perform a large eddy simulation of soot production in a model combustor representative of gas turbine combustion chambers. It is shown that the three-equation model is able to provide a good estimation of soot volume fraction and information on PSD in complex geometries for a low computational time.

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Section: Analysis Of Resultsmentioning

confidence: 99%

Section: Analysis Of Resultsmentioning

confidence: 99%

A three-equation model for the prediction of soot emissions in LES of gas turbines

Franzelli

Vié

Darabiha

2019

Proceedings of the Combustion Institute

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“…As shown, it is found that the free energy barrier of CH 4 molecule elimination from reaction (3) is 82.95 kcal/mol, while the CH 3 radical elimination from reaction (4) is only 73.40 kcal/mol. This indicates that it is more likely to directly eliminate CH 3 radical using reaction (4). To further validate this conclusion, the rate constant k 3 of reaction (3) and rate constant k 4 of reaction (4) are calculated at a high temperature (ie, 1000, 2000, and 2500 K) using TST theory.…”

Section: T a B L Ementioning

confidence: 89%

“…As the initial reaction steps of HMDSO combustion, HMDSO decomposition reactions are of considerable importance as they have a great influence on the subsequent chemical reactions and accuracy of combustion simulations. [4,6,7] Experimental studies on HMDSO decomposition reactions have been conducted by Chernyshev et al [8] at 675 C in a flow reactor. Based on the initial products, two possible reaction schemes were proposed.…”

Section: Introductionmentioning

confidence: 99%

Identification of decomposition reactions for HMDSO organosilicon using quantum chemical calculations

Huang

Chen

Zhou

2020

Int J of Quantum Chemistry

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Hexamethyldisiloxane [HMDSO, (CH 3) 3-SiOSi-(CH 3) 3 ] is an important precursor for SiO 2 formation during flame-based silica material synthesis. As a result, HMDSO reactions in flame have been widely investigated experimentally, and many results have indicated that HMDSO decomposition reactions occur very early in this process. In this paper, quantum chemical calculations are performed to identify the initial decomposition of HMDSO and its subsequent reactions using the density functional theory at the level of B3LYP/6-311+G (d, p). Four reaction pathways-(a) Si O bond dissociation of HMDSO, (b) Si C bond dissociation of HMDSO, (c) dissociation and recombination of Si O and Si C bonds, and (d) elimination of a methane molecule from HMDSO-have been examined and identified. From the results, it is found that the barrier of 84.38 kcal/mol and Si O bond dissociation energy of 21.55 kcal/mol are required for the initial decomposition reaction of HMDSO in the first pathway, but the highest free energy barrier (100.69 kcal/mol) is found in the third reaction pathway. By comparing the free energy barriers and reaction rate constants, it is concluded that the most possible initial decomposition reaction of HMDSO is to eliminate the CH 3 radical by Si C bond dissociation.

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“…There is a vast of publications that concern different materials. Rittler et al [5] performed large eddy simulations of the production of silica nanoparticles from flame spray pyrolysis using ethanol/hexamethyldisiloxane (HMDSO) mixtures as precursor and oxygen as dispersion gas. This study focuses on the understanding of the interaction between spray evaporation, gas phase combustion, and synthesis of nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Single Iron(III) Nitrate Nonahydrate/Ethanol Droplet Evaporation in Humid Air

Narasu¹,

Keller²,

Kohns³

et al. 2020

World Congress on Momentum, Heat and Mass Transfer

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The heating and evaporation of spherically symmetric droplets consisting of a precursor solution of iron(III) nitrate nonahydrate (INN) and ethanol for nanoparticle synthesis in spray flames is studied numerically. The multicomponent droplets are at standard conditions and the evaporation is initiated through the elevated temperature of the convective ambient air. The liquid mixture properties of INN and ethanol used in the model are fits to new experimental data which are valid in the temperature range of 293.15 K through 333.15 K and for mass fractions of INN in ethanol up to 0.34. In general, there are two different pathways through which the nanoparticle synthesis may occur from the precursor solution. In the first pathway, the particle forms directly inside the liquid precursor solution, and in the second pathway, the droplet is transferred entirely into the gas phase from which the nanoparticle may form. The INN/ethanol precursor droplet is treated as a three-component solution consisting of ethanol, iron(III) nitrate, and water, where the INN consists of the latter two. The process is initially governed by the ethanol evaporation and later by water evaporation since ethanol is more volatile component. Further decomposition and liquid-phase reactions may occur inside the precursor droplet, eventually leaving over an iron (III) nitrate particle or transferring the iron (III) nitrate into the gas phase, which happens beyond the thermal decomposition temperature of 403 K beyond which the iron (III) nitrate may decompose into gaseous Fe2O3, so that the entire INN/ethanol droplet transforms into the gas phase. The study presents simulations of the evaporation of the INN/ethanol droplet for both situations.

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Large eddy simulations of nanoparticle synthesis from flame spray pyrolysis

Cited by 56 publications

References 49 publications

A three-equation model for the prediction of soot emissions in LES of gas turbines

A three-equation model for the prediction of soot emissions in LES of gas turbines

Identification of decomposition reactions for HMDSO organosilicon using quantum chemical calculations

Numerical Study of Single Iron(III) Nitrate Nonahydrate/Ethanol Droplet Evaporation in Humid Air

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