This work describes the development of a method for the global hydrodynamic stability analysis of diffusion flames. The low-Machnumber (LMN) Navier-Stokes (NS) equations for reacting flows are solved together with a transport equation for the mixture fraction describing the local composition of the fluid. The equations are solved by the spectral-element code NEK5000 with Legendre polynomial reconstruction of degree twelve and second-order accurate Runge-Kutta time integration scheme. In order to compute the base flow for the stability analysis, a selective frequency damping approach has been employed. The global stability analysis has been performed by a matrix-free time-stepper algorithm applied to the LMN-NS equations, using an Arnoldi method to compute the most unstable modes. Moreover, a numerical linearization of the governing equation is employed, which allows one to study the stability of diffusion flames without the direct evaluation and storage of the linearized operator. Therefore, a remarkable reduction of the storage capacity is achieved and a more flexible numerical approach is obtained. The numerical model has been validated by comparison with the results for the axisymmetric diffusion flame available in the literature.

Global stability analysis of lifted diffusion flames / Mancini, C.; Farano, M.; De Palma, P.; Robinet, J. C.; Cherubini, S.. - In: ENERGY PROCEDIA. - ISSN 1876-6102. - 126:(2017), pp. 867-874. [10.1016/j.egypro.2017.08.292]

Global stability analysis of lifted diffusion flames

Farano, M.;De Palma, P.
;
Cherubini, S.
2017-01-01

Abstract

This work describes the development of a method for the global hydrodynamic stability analysis of diffusion flames. The low-Machnumber (LMN) Navier-Stokes (NS) equations for reacting flows are solved together with a transport equation for the mixture fraction describing the local composition of the fluid. The equations are solved by the spectral-element code NEK5000 with Legendre polynomial reconstruction of degree twelve and second-order accurate Runge-Kutta time integration scheme. In order to compute the base flow for the stability analysis, a selective frequency damping approach has been employed. The global stability analysis has been performed by a matrix-free time-stepper algorithm applied to the LMN-NS equations, using an Arnoldi method to compute the most unstable modes. Moreover, a numerical linearization of the governing equation is employed, which allows one to study the stability of diffusion flames without the direct evaluation and storage of the linearized operator. Therefore, a remarkable reduction of the storage capacity is achieved and a more flexible numerical approach is obtained. The numerical model has been validated by comparison with the results for the axisymmetric diffusion flame available in the literature.
2017
Global stability analysis of lifted diffusion flames / Mancini, C.; Farano, M.; De Palma, P.; Robinet, J. C.; Cherubini, S.. - In: ENERGY PROCEDIA. - ISSN 1876-6102. - 126:(2017), pp. 867-874. [10.1016/j.egypro.2017.08.292]
File in questo prodotto:
File Dimensione Formato  
MAncini-EnergyProcedia2017.pdf

accesso aperto

Tipologia: Versione editoriale
Licenza: Creative commons
Dimensione 978.87 kB
Formato Adobe PDF
978.87 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11589/117922
Citazioni
  • Scopus 1
  • ???jsp.display-item.citation.isi??? 1
social impact