Numerical Analysis of Radiant Section of Fired Heater Focused on the Effect of Wall-Tube Distance

Hájek, Jiří; Jegla, Z.; Vondál, Jiří

doi:10.1016/b978-0-444-63456-6.50056-9

Cited by 4 publications

(2 citation statements)

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“…The procedure is based on the social behavior of different species in nature, using effects of individuality and sociability in order to determine an optimal search direction. The algorithm is given by: (11) where k is the iteration step index, r1 and r2 are uniform random numbers varying from 0 to 1, and the constants 1 and 2, taken as 2 in this study, define the search range. The best position obtained by the i th individual (i) is the responsible for the individuality, and the best position obtained by all the individuals (g) is the responsible for the sociability.…”

Section: Optimization Modelmentioning

confidence: 99%

“…Radiation, the main heat transfer mechanism associated with combustion, has also been the subject of interest and numerous models have been proposed in order to predict its behavior, especially in the presence of participating medium [8]. Using these advances in models describing the heat transfer and fluid flow mechanisms present in combustion systems, many studies have been conducted to evaluate the performance of real fired heaters using CFD software [9][10][11]. These evaluations successfully allowed observing the influence of operating variables on the heat transfer to the coils and the effects of non-uniform heat flux distribution described above.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of Extended Surfaces on Tubes of the Radiant Section of Fired Heaters

Silva¹,

Colaço²

2020

Preprint

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This paper proposes the use of non-uniform extended surfaces installed externally to the tubes of the radiation section of fired heaters, in order to obtain a better heat flux distribution to the coils. To this end, the heat transfer mechanisms present in such equipment were studied through computational fluid dynamics (CFD), using simplified geometries that represent typical sizes of fired heaters. Also, a simplified model for the combustion was considered. Although this model oversimplifies the physics of the problem, it was able to give satisfactory results for the parameters being optimized, considering the main objective of this paper, that is to minimize the non-uniformity of heat flux in the tubes of the radiant section of fired heaters. It was possible to obtain optimized geometric parameters for different types of extended surfaces evaluated, coupling the results of these models with the Particle Swarm optimization method through the use of a response surface technique,. The results indicate a significant improvement in the uniformity of the heat flux distribution to the tubes through the use of the proposed extended surfaces. Thus, this solution reveals to be an interesting alternative to reduce the risks of fluid degradation and coking formation. Future studies must investigate the non-uniformity of the heat flux due to the presence of the flame and consider the interaction between the reactive flow and the participating medium. Nevertheless, this paper presents some results that justify the optimization of such extended surfaces taking into consideration thermal radiation.

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Section: Optimization Modelmentioning

confidence: 99%