Efficient Implementation of Chemistry in Computational Combustion

Pope, Stephen B.; Ren, Zhuyin

doi:10.1007/s10494-008-9145-3

Cited by 37 publications

(16 citation statements)

References 53 publications

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“…Operator splitting (OS) methods have been previously applied to a wide range of problems, including groundwater transport simulations [6], air pollution modelling [7] and combustion-reaction problems [17]. They provide a framework to deal separately with the transport and the chemical reaction steps and therefore simplify the resolution of the system.…”

Section: Operator Splitting Methodsmentioning

confidence: 99%

Modelling in-situ upgrading of heavy oil using operator splitting method

et al. 2015

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The in-situ upgrading (ISU) of bitumen and oil shale is a very challenging process to model numerically because of the large number of components that need to be modelled using a system of equations that are both highly non-linear and strongly coupled. Operator splitting methods are one way of potentially improving computational performance. Each numerical operator in a process is modelled separately, allowing the best solution method to be used for the given numerical operator. A significant drawback to the approach is that decoupling the governing equations introduces an additional source of numerical error, known as the splitting error. The best splitting method for modelling a given process minimises the splitting error whilst improving computational performance compared to a fully implicit approach. Although operator splitting has been widely used for the modelling of reactive-transport problems, it has not yet been applied to the modelling of ISU. One reason is that it is not clear which operator splitting technique to use. Numerous such techniques are described in the literature and each leads to a different splitting error. While this error has been extensively analysed for linear operators for a wide Julien Maes range of methods, the results cannot be extended to general non-linear systems. It is therefore not clear which of these techniques is most appropriate for the modelling of ISU. In this paper, we investigate the application of various operator splitting techniques to the modelling of the ISU of bitumen and oil shale. The techniques were tested on a simplified model of the physical system in which a solid or heavy liquid component is decomposed by pyrolysis into lighter liquid and gas components. The operator splitting techniques examined include the sequential split operator (SSO), the Strang-Marchuk split operator (SMSO) and the iterative split operator (ISO). They were evaluated on various test cases by considering the evolution of the discretization error as a function of the time-step size compared with the results obtained from a fully implicit simulation. We observed that the error was least for a splitting scheme where the thermal conduction was performed first, followed by the chemical reaction step and finally the heat and mass convection operator (SSO-CKA). This method was then applied to a more realistic model of the ISU of bitumen with multiple components, and we were able to obtain a speed-up of between 3 and 5.

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Section: Operator Splitting Methodsmentioning

confidence: 99%

Modelling in-situ upgrading of heavy oil using operator splitting method

et al. 2015

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“…To the authors' experiences in the usage of the QSS method, the reduction in the species number is not proportional to the rate of speed-up of the computation, and for turbulent combustion modeling with large fluctuations, the stability of the numerical scheme diminishes and the solution converges much slower. Meanwhile, other methodologies such as dimension reduction or tabulation have been developed to accelerate reactive-flow simulations, e.g., the work of Pope and coworkers [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Development of efficient and accurate skeletal mechanisms for hydrocarbon fuels and kerosene surrogate

Zhong

Zhang

et al. 2015

Acta Mech. Sin.

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In this paper, the methodology of the directed relation graph with error propagation and sensitivity analysis (DRGEPSA), proposed by Niemeyer et al. (Combust Flame 157:1760-1770, and its differences to the original directed relation graph method are described. Using DRGEPSA, the detailed mechanism of ethylene containing 71 species and 395 reaction steps is reduced to several skeletal mechanisms with different error thresholds. The 25-species and 131-step mechanism and the 24-species and 115-step mechanism are found to be accurate for the predictions of ignition delay time and laminar flame speed. Although further reduction leads to a smaller skeletal mechanism with 19 species and 68 steps, it is no longer able to represent the correct reaction processes. With the DRGEPSA method, a detailed mechanism for n-dodecane considering low-temperature chemistry and containing 2115 species and 8157 steps is reduced to a much smaller mechanism with 249 species and 910 steps while retaining good accuracy. If considering only high-temperature (higher than 1000 K) applications, the detailed mechanism can be simplified to even smaller mechanisms with 65 species and 340 steps or 48 species and 220 steps. Furthermore, a detailed mechanism for a kerosene surrogate having 207 species and 1592 steps is reduced with various error thresholds and the results show that the 72-species and 429-step mechanism and the 66-species and 392-step mechanism are capable of predicting correct combustion properties compared to those of the detailed mechanism. It is well recognized that kinetic mechanisms can be effectively used in computations only after they are reduced to an acceptable size level for computation capacity and at the same time retaining accuracy. Thus, the skeletal mechanisms generated from the present work are expected to be useful for the application of kinetic mechanisms of hydrocarbons to numerical simulations of turbulent or supersonic combustion.

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“…Another strategy consists in reducing the modeling complexity and associated computational effort by more efficient handling of the time and spatial scales, while guaranteeing reliable predictive capabilities. This is exemplified by chemical kinetics reduction methods [4,5], tabulation techniques [6,7], or artificial flame thickening schemes [8] which all focus on an improved handling of time and spatial scales. The spatial filtering exploited in large eddy simulations (LES) relies on similar ideas.…”

Section: Introductionmentioning

confidence: 99%

Time–space adaptive numerical methods for the simulation of combustion fronts

Duarte¹,

Descombes²,

Tenaud³

et al. 2013

Combustion and Flame

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To cite this version:Max Duarte, Stéphane Descombes, Christian Tenaud, Sébastien Candel, Marc Massot. Time-space adaptive numerical methods for the simulation of combustion fronts. Combustion and Flame, Elsevier, 2013, 160 (6) AbstractThis paper presents a new computational strategy for the simulation of combustion fronts based on adaptive time operator splitting and spatial multiresolution. High-order and dedicated onestep solvers compose the splitting scheme for the reaction, diffusion, and convection subproblems, to independently cope with their inherent numerical difficulties and to properly solve the corresponding temporal scales. Adaptive and thus highly compressed spatial representations for localized fronts originating from multiresolution analysis result in important reductions of memory usage, and hence numerical simulations with sufficiently fine spatial resolution can be performed with standard computational resources. The computational efficiency is further enhanced by splitting time steps established beyond standard stability constraints associated to mesh size or stiff source time scales. The splitting time steps are chosen according to a dynamic splitting technique relying on solid mathematical foundations, which ensures error control of the time integration and successfully discriminates time-varying multi-scale physics. For a given semidiscretized problem, the solution scheme provides dynamic accuracy estimates that reflect the quality of numerical results in terms of numerical errors of integration and compressed spatial representations, for general multi-dimensional problems modeled by stiff PDEs. The strategy is efficiently applied to simulate the propagation of laminar premixed flames interacting with vortex structures, as well as various configurations of self-ignition processes of diffusion flames in similar vortical hydrodynamics fields. A detailed study of the error control is provided and show the potential of the approach. It yields large gains in CPU time, while consistently describing a broad spectrum of space and time scales as well as different physical scenarios.

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Efficient Implementation of Chemistry in Computational Combustion

Cited by 37 publications

References 53 publications

Modelling in-situ upgrading of heavy oil using operator splitting method

Modelling in-situ upgrading of heavy oil using operator splitting method

Development of efficient and accurate skeletal mechanisms for hydrocarbon fuels and kerosene surrogate

Time–space adaptive numerical methods for the simulation of combustion fronts

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