Transient detailed numerical simulation of the combustion of carbon particles

Stauch, R.; Maas, Ulrich

doi:10.1016/j.ijheatmasstransfer.2009.02.047

Cited by 35 publications

(8 citation statements)

References 28 publications

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“…The high complexity of the pulverised and fluidised bed coal combustion, however, has motivated the analysis of unsteady combustion of single coal particles. In this context, both one-dimensional (spherically symmetric) [22,38] and two-dimensional [21,11] simulations of the combustion process have been performed.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity analysis of an unsteady char particle combustion

Hassan

Sayadi

Chenadec

et al. 2021

Fuel

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Simulations of unsteady char particle combustion rely on various models that are necessary in order to correctly predict the governing flow and combustion processes. These models, in turn, rely on model parameters, which are determined by experiments or small scale simulations and contain a certain level of uncertainty. It is therefore, essential to correctly determine the sensitivities of quantities of interest measured using such simulations, with respect to the existing parameters. In this study, a discrete adjoint algorithm is employed to extract sensitivities of various quantities of interest with respect to physical and model parameters. This adjoint framework bears a great advantage in cases where a large input space is analyzed, since a single forward and backward sweep provides sensitivity information with respect to all parameters of interest. Sensitivities are extracted for relevant quantities of interest, such as burning rate and particle temperature, and are then compared as free stream composition changes from air to oxy atmosphere. The evolution of sensitivities in time is shown to be dependent on the selected quantity of interest. Model sensitivities with respect to heterogeneous reaction parameters (oxidation of carbon, in particular) are shown to be the highest, whereas the sensitivities with respect to free stream composition are shown to be significantly lower.

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Section: Introductionmentioning

confidence: 99%

Sensitivity analysis of an unsteady char particle combustion

Hassan

Sayadi

Chenadec

et al. 2021

Fuel

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“…An acceptance of this assumption was first discussed in experimental works by Smith and Gudmundsen. () Recently, Stauch and Maas () carried out transient detailed numerical simulations of the combustion of carbon particles, which showed that the characteristic values of the burning process are only dependent on the current particle diameter, independent of its previous evolution. ()…”

Section: Introductionmentioning

confidence: 99%

“…[11] Recently, Stauch and Maas [12] carried out transient detailed numerical simulations of the combustion of carbon particles, which showed that the characteristic values of the burning process are only dependent on the current particle diameter, independent of its previous evolution. [12] It should be noted that in spite of numerous works carried out in 80th about the modelling of particle combustion and gasification, until now there are few numerical studies about the influence of convection in such processes. An overview of the first efforts to take into account the impact of particle velocity on the carbon consumption rates can be found in Chomiak and Sarofim.…”

Section: Introductionmentioning

confidence: 99%

Particle resolved simulations of carbon oxidation in a laminar flow

Safronov

Kestel

Nikrityuk³

et al. 2014

Can J Chem Eng

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This work is devoted to the numerical study of the impact of the Reynolds number and the ambient gas temperature on the partial oxidation of a single moving coal particle. The model includes six gaseous chemical species, three semi‐global heterogeneous surface reactions, and three homogeneous gas reactions. The Navier–Stokes equations coupled with the energy and species conservation equations were used to solve the problem. The diameter of the particles considered was set up as 2 mm and 200normalμm. An analysis of the simulations related to the influence of particle Reynolds numbers on integral characteristics such as surface‐averaged carbon consumption rates revealed that the oxidation rate increases with increasing gas velocity, which is logical. However, the increase in the particle Reynolds number leads to the prolongation of the kinetically controlled regime from lower to higher temperatures, which is explained by the enhancement of the mass transfer between the particle and the surrounding gas. Using visualization of the temperature and species mass fraction distributions around the reacting particles predicted numerically, the three well‐known basic oxidation regimes, namely the diffusion‐controlled, transitional, and kinetically controlled regimes are described, taking into account the impact of the particle Reynolds number on the dynamics of oxidation. The influence of radiation in the gas phase on oxidation rates was studied numerically using P1 radiation model. Additionally the behaviour of heterogeneous Damköhler numbers, Thiele modulus and effectiveness factors depending on the ambient temperature and particle Reynolds number was analyzed and discussed.

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“…see [10][11][12][13][14][15][16][17]. Analysis of the works shows that the so-called moving-gridbased models are generally used where conservation equations are solved in solid and gas phases using separate grids conforming to the shape of the particle interface.…”

Section: Introductionmentioning

confidence: 99%

“…In the case of the shrinkingcore model, which assumes that a particle diameter is constant, the particle density change is defined using interfacial heat and the species concentration balance. In particular, recent works [15] and [17] are examples of the two approaches, respectively. The disadvantage of the moving-grid methods is their complexity in 2D and 3D implementations.…”

Section: Introductionmentioning

confidence: 99%