Modelling PAH curvature in laminar premixed flames using a detailed population balance model

Yapp, Edward Kien Yee; Wells, Clive G.; Akroyd, Jethro; Mosbach, Sebastian; Xu, Rong; Kraft, Markus

doi:10.1016/j.combustflame.2016.10.004

Cited by 29 publications

(23 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This amount of pentagon integration is higher than the values 28-49% found previously for mature carbon particulates. 26,33 These lower values can be explained by the age of the particles; indeed, the fringe analysis for carbon particulates sampled from the late stages of the flame have considerably flatter and longer fringes, indicating a carbonization process leading to removal of embedded pentagonal rings.…”

Section: Resultsmentioning

confidence: 99%

Flexoelectricity and the Formation of Carbon Nanoparticles in Flames

et al. 2018

Self Cite

View full text Add to dashboard Cite

The formation of carbon nanoparticles in flames involves a nucleation step that remains poorly understood. Experimentally, carbon nuclei formation is known to depend strongly on the electrical aspects of combustion but modes of interaction between charged species in the flame and carbon precursors have yet to be found. We present evidence for flexoelectrically polarised aromatics contributing to carbon nanoparticulate nucleation. We imaged the nascent nanoparticles using high resolution transmission electron microscopy, which revealed that the majority of aromatics in the early carbon nanoparticles are fullerene-like and curved. The curvature induces a significant molecular flexoelectric dipole moment in the polyaromatic hydrocarbons. This electric polarization allows these molecules to strongly interact with chemi-ions produced during combustion, which we demonstrate using electronic structure calculations. The results indicate that the physical interaction between fullerene-like polar aromatics and chemi-ions is critically assisting the nucleation, and opens a new route to reduce pollution and improve flame-produced nanomaterials.

show abstract

Section: Resultsmentioning

confidence: 99%

Flexoelectricity and the Formation of Carbon Nanoparticles in Flames

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…Recent high resolution transmission electron microscopy (HRTEM) studies have shown that significant fractions of aromatic molecules in soot contain non-hexagonal rings [5,6]. Curvature analysis of the fringes using geometrical [5] and statistical models of the curvature [7] showed that the majority of fringes contained a single inflection point indicating pentagon integration, with 28-49% of the fringes containing curvature indicating >1 pentagon. The range of pentagon integration was predicted to span 1-3 pentagons.…”

Section: Introductionmentioning

confidence: 99%

Polar curved polycyclic aromatic hydrocarbons in soot formation

Martin

Bowal

Menon

et al. 2019

Proceedings of the Combustion Institute

Self Cite

View full text Add to dashboard Cite

Recent experimental and computational work suggests that a significant number of curved aromatic molecules are found in carbon materials such as soot. These curved aromatic molecules contain a substantial dipole moment (4-6.5 debye for the sizes seen in soot molecules containing 10-20 rings). In this paper we employ electronic structure calculations to determine the earliest onset of curvature integration. We found an interplay between the σ bonding inducing curvature and the π bonding resisting curvature with a size of six rings, with at least one being pentagonal, required to curve an aromatic molecule. The interactions between polar curved arenes and other species are then considered with particular focus on nascent soot formation, indicating that heterogeneous, not homogeneous, nucleation could be a significant factor in soot formation.

show abstract

“…Based on the primary particle model and the KMC-Aromatic Site (KMC-ARS) model [41,42] for PAH growth, Kraft and co-workers have developed more detailed population balance models for soot by considering the detailed composition (i.e. PAHs) of soot particles [25,36,37,41,42,[45][46][47]. These models describe soot particles as aggregates composed of primary particles, which are in turn composed of individual PAHs, rather than just carbon atoms as in previous soot models.…”

Section: Introductionmentioning

confidence: 99%

Modelling soot formation in a benchmark ethylene stagnation flame with a new detailed population balance model

Hou

Lindberg

Manuputty

et al. 2019

Combustion and Flame

Self Cite

View full text Add to dashboard Cite

Numerical simulation of soot formation in a laminar premixed burner-stabilised benchmark ethylene stagnation flame was performed with a new detailed population balance model employing a two-step simulation methodology. In this model, soot particles are represented as aggregates composed of overlapping primary particles, where each primary particle is composed of a number of polycyclic aromatic hydrocarbons (PAHs). Coordinates of primary particles are tracked, which enables simulation on particle morphology and provides more quantities that are directly comparable to experimental observations. Parametric sensitivity study on the computed particle size distributions (PSDs) shows that the rate of production of pyrene and the collision efficiency have the most significant effect on the computed PSDs. Sensitivity of aggregate morphology to the sintering rate is studied by analysing the simulated primary particle size distributions (PPSDs) and transmission electron microscopy (TEM) images. The capability of the new model to predict PSDs in a premixed stagnation flame is investigated. Excellent agreement between the computed and measured PSDs is obtained for large burner-stagnation plate separation (≥ 0.7 cm) and for particles with mobility diameter larger than 6 nm, demonstrating the ability of this new model to describe the coagulation process of aggregate particles.

show abstract

Modelling PAH curvature in laminar premixed flames using a detailed population balance model

Cited by 29 publications

References 61 publications

Flexoelectricity and the Formation of Carbon Nanoparticles in Flames

Flexoelectricity and the Formation of Carbon Nanoparticles in Flames

Polar curved polycyclic aromatic hydrocarbons in soot formation

Modelling soot formation in a benchmark ethylene stagnation flame with a new detailed population balance model

Contact Info

Product

Resources

About