Influence of air preheat temperature and excess air in a reverse flow combustor

Influence of air preheat temperature and excess air in a reverse flow combustor

Djamel BenmenineAbdelhalim Bentebbiceh 

Laboratoire de Mécanique Énergétique et Systèmes de Conversion, Université des Sciences et de Technologie Houari Boumédiène BP32, El-Alia, 16111 Bab-Ezzouar, Alger, Algeria

Laboratoire de développement des énergies nouvelles et renouvelables en zones arides (LENREZA), Université Kasdi Merbah Ouargla BP 511, 30000 Ouargla, Algeria

Corresponding Author Email: 
benmenine.djamel@tecnico.ulisboa.pt
Page: 
93-111
|
DOI: 
https://doi.org/10.3166/I2M.17.93-111
Received: 
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Accepted: 
|
Published: 
31 March 2018
| Citation

OPEN ACCESS

Abstract: 

The purpose of this study is to investigate The influence of the air preheat temperature and excess air coefficient on the combustion process. For that, Combustion in a stagnation point reverse flow small-scale cylindrical combustor is numerically simulated. The burner and the exhaust port are located at the top of the combustor and the bottom end is closed. The fuel is natural gas. Turbulence is modelled using either the Reynolds stress model or large eddy simulation (LES). In the former case, two different combustion models are used, namely the eddy dissipationfinite rate (ED-FR) model with a two-step reaction mechanism, and the eddy dissipation concept (EDC) along with a detailed reaction mechanism. In the case of LES, only the ED-FR model is employed.. Through this study, it was found that The temperature field becomes more uniform when the excess air coefficient or the air preheat temperature increase. If the excess air coefficient increases, the maximum and average temperatures in the combustor are lower, as well as the heat release rate, the scalar gradients are smoother, the reaction zone becomes wider, and moves away from the burner. The increase of the preheat air temperature yields an increase of the maximum and averaged temperatures in the combustor, and an increase of the heat release rate, with a thinner and shorter reaction zone that is closer to the burner. Satisfactory predictions of the NO emissions were obtained.

Keywords: 

reverse-flow combustor, eddy dissipation concept, air-preheat temperature, excess air

1. Introduction
2. Mathematical modelling
3. Reverse flow combustor
4. Computational details
5. Results and discussion
6. Conclusions
Acknowledgements

This work was supported by: FCT, through IDMEC, under LAETA, project UID/EMS/50022/2013 and Ministry of Higher Education and Scientific Research in Algeria

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