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An isothermal analysis of curved-vane and flat-vane swirlers for burners

Parra-Santos, Teresa; Perez-Dominguez, J. R.; Szász, Robert-Zoltán LU and Castro-Ruiz, F. (2015) In Engineering Computations 32(3). p.668-686
Abstract
Purpose - One current trend in burner technology is to obtain high efficiency while keeping low levels of NOx emissions. A swirling flow in combustion ensures a fixed position of a compact flame. Therefore, it is necessary to design efficient swirlers. Flow patterns are simulated for the different swirl devices proposed in this work. Two axial-swirlers are studied: one based on curve-vanes consisting of a straight line with an arc of a circle as the trailing edge and the other is the common flat-vanes. The purpose of this paper is to assess the accuracy of different swirl generators using a well-known benchmark test case. Design/methodology/approach - This work deals with modelling the swirler using two approaches: the general purpose... (More)
Purpose - One current trend in burner technology is to obtain high efficiency while keeping low levels of NOx emissions. A swirling flow in combustion ensures a fixed position of a compact flame. Therefore, it is necessary to design efficient swirlers. Flow patterns are simulated for the different swirl devices proposed in this work. Two axial-swirlers are studied: one based on curve-vanes consisting of a straight line with an arc of a circle as the trailing edge and the other is the common flat-vanes. The purpose of this paper is to assess the accuracy of different swirl generators using a well-known benchmark test case. Design/methodology/approach - This work deals with modelling the swirler using two approaches: the general purpose Computational fluid dynamics (CFD) solver Ansys-Fluent (R) and the suite of libraries OpenFOAM (R) to solve the Reynolds Averaged Navier Stokes equations, showing there is a slight deviation between both approaches. Their performance involves analyzing not only the Swirl number but also the size of the recirculation zones in the test chamber. A subsequent process on the flow patterns was carried out to establish the intensity of segregation which provides insight into the quality of mixing. Findings - CFD models are feasible tools to predict flow features. It was found that numerical results tend to reduce the inner recirculation zone (IRZ) radial size. Further, an increase of the swirl number involves larger IRZ and a smaller outer recirculation zone (ORZ). The curved swirler displays a better axi-symmetric behaviour than flat vanes. There is weak influence of the chord vanes on the swirl number. The number of vanes is a compromise of head loses and guidance of the flow. Originality/value - The paper offers two different approaches to solve turbulent swirling flows. One based in a general contrasted commercial tool and other using open source code. Both models show similar performance. An innovative set up for an axial swirler different from the conventional flat vanes was proposed. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
CFD, Coaxial jets, Mixing, Swirl number, Turbulence
in
Engineering Computations
volume
32
issue
3
pages
668 - 686
publisher
Emerald Group Publishing Limited
external identifiers
  • wos:000355829900006
  • scopus:84929240918
ISSN
0264-4401
DOI
10.1108/EC-06-2013-0149
language
English
LU publication?
yes
id
5a64d10e-117d-40ba-ba62-82e4c52aba44 (old id 7606133)
date added to LUP
2015-07-22 08:45:04
date last changed
2017-07-23 04:01:34
@article{5a64d10e-117d-40ba-ba62-82e4c52aba44,
  abstract     = {Purpose - One current trend in burner technology is to obtain high efficiency while keeping low levels of NOx emissions. A swirling flow in combustion ensures a fixed position of a compact flame. Therefore, it is necessary to design efficient swirlers. Flow patterns are simulated for the different swirl devices proposed in this work. Two axial-swirlers are studied: one based on curve-vanes consisting of a straight line with an arc of a circle as the trailing edge and the other is the common flat-vanes. The purpose of this paper is to assess the accuracy of different swirl generators using a well-known benchmark test case. Design/methodology/approach - This work deals with modelling the swirler using two approaches: the general purpose Computational fluid dynamics (CFD) solver Ansys-Fluent (R) and the suite of libraries OpenFOAM (R) to solve the Reynolds Averaged Navier Stokes equations, showing there is a slight deviation between both approaches. Their performance involves analyzing not only the Swirl number but also the size of the recirculation zones in the test chamber. A subsequent process on the flow patterns was carried out to establish the intensity of segregation which provides insight into the quality of mixing. Findings - CFD models are feasible tools to predict flow features. It was found that numerical results tend to reduce the inner recirculation zone (IRZ) radial size. Further, an increase of the swirl number involves larger IRZ and a smaller outer recirculation zone (ORZ). The curved swirler displays a better axi-symmetric behaviour than flat vanes. There is weak influence of the chord vanes on the swirl number. The number of vanes is a compromise of head loses and guidance of the flow. Originality/value - The paper offers two different approaches to solve turbulent swirling flows. One based in a general contrasted commercial tool and other using open source code. Both models show similar performance. An innovative set up for an axial swirler different from the conventional flat vanes was proposed.},
  author       = {Parra-Santos, Teresa and Perez-Dominguez, J. R. and Szász, Robert-Zoltán and Castro-Ruiz, F.},
  issn         = {0264-4401},
  keyword      = {CFD,Coaxial jets,Mixing,Swirl number,Turbulence},
  language     = {eng},
  number       = {3},
  pages        = {668--686},
  publisher    = {Emerald Group Publishing Limited},
  series       = {Engineering Computations},
  title        = {An isothermal analysis of curved-vane and flat-vane swirlers for burners},
  url          = {http://dx.doi.org/10.1108/EC-06-2013-0149},
  volume       = {32},
  year         = {2015},
}