The effects of unburned-gas temperature on intrinsic instability of premixed flames at high Lewis numbers under the adiabatic and non-adiabatic conditions

We treated numerically premixed flames at high Lewis numbers under the adiabatic and non-adiabatic conditions to elucidate the effects of unburned-gas temperature on intrinsic instability. Numerical calculations of two-dimensional unsteady reactive flow were performed, based on the compressible Navi...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Thwe Thwe Aung, Toshiyuki KATSUMI, Satoshi KADOWAKI
Formato:	article
Lenguaje:	EN
Publicado:	The Japan Society of Mechanical Engineers 2017
Materias:	premixed flame intrinsic instability high lewis number unburned-gas temperature heat loss dispersion relation burning velocity Mechanical engineering and machinery TJ1-1570
Acceso en línea:	https://doaj.org/article/f147b1d80f9c41f6b33d4252e58ece9f
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:f147b1d80f9c41f6b33d4252e58ece9f
record_format	dspace
spelling	oai:doaj.org-article:f147b1d80f9c41f6b33d4252e58ece9f2021-11-26T07:02:12ZThe effects of unburned-gas temperature on intrinsic instability of premixed flames at high Lewis numbers under the adiabatic and non-adiabatic conditions2187-974510.1299/mej.16-00477https://doaj.org/article/f147b1d80f9c41f6b33d4252e58ece9f2017-03-01T00:00:00Zhttps://www.jstage.jst.go.jp/article/mej/4/2/4_16-00477/_pdf/-char/enhttps://doaj.org/toc/2187-9745We treated numerically premixed flames at high Lewis numbers under the adiabatic and non-adiabatic conditions to elucidate the effects of unburned-gas temperature on intrinsic instability. Numerical calculations of two-dimensional unsteady reactive flow were performed, based on the compressible Navier-Stokes equation including one-step chemical reaction. Lewis numbers higher than unity were adopted, and radiative heat loss was employed. Superimposing a sinusoidal disturbance with sufficiently small amplitude on a stationary planar flame, we obtained the relation between the growth rate and wave number, so-called dispersion relation. When the Lewis number was higher than unity, the growth rate was small and the unstable range was narrow, compared with premixed flames at Lewis number of unity, which was because of the weakness of intrinsic instability due to diffusive-thermal effects. As the unburned-gas temperature became higher, the growth rate increased and the unstable range widened. This was because of the increase of the burning velocity of a planar flame. Taking account of radiative heat loss, we obtained small growth rates and narrow unstable range. To study the characteristics of cellular flames generated by intrinsic instability, we superimposed a disturbance with the critical wave number corresponding to the maximum growth rate. The superimposed disturbance evolved, and a cellular flame formed. The burning velocity of a cellular flame normalized by that of a planar flame decreased as the unburned-gas temperature became higher. As the heat loss became larger, the normalized burning velocity of a cellular flame decreased. This indicated that the heat loss inhibited the instability of premixed flames at high Lewis numbers.Thwe Thwe AungToshiyuki KATSUMISatoshi KADOWAKIThe Japan Society of Mechanical Engineersarticlepremixed flameintrinsic instabilityhigh lewis numberunburned-gas temperatureheat lossdispersion relationburning velocityMechanical engineering and machineryTJ1-1570ENMechanical Engineering Journal, Vol 4, Iss 2, Pp 16-00477-16-00477 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	premixed flame intrinsic instability high lewis number unburned-gas temperature heat loss dispersion relation burning velocity Mechanical engineering and machinery TJ1-1570
spellingShingle	premixed flame intrinsic instability high lewis number unburned-gas temperature heat loss dispersion relation burning velocity Mechanical engineering and machinery TJ1-1570 Thwe Thwe Aung Toshiyuki KATSUMI Satoshi KADOWAKI The effects of unburned-gas temperature on intrinsic instability of premixed flames at high Lewis numbers under the adiabatic and non-adiabatic conditions
description	We treated numerically premixed flames at high Lewis numbers under the adiabatic and non-adiabatic conditions to elucidate the effects of unburned-gas temperature on intrinsic instability. Numerical calculations of two-dimensional unsteady reactive flow were performed, based on the compressible Navier-Stokes equation including one-step chemical reaction. Lewis numbers higher than unity were adopted, and radiative heat loss was employed. Superimposing a sinusoidal disturbance with sufficiently small amplitude on a stationary planar flame, we obtained the relation between the growth rate and wave number, so-called dispersion relation. When the Lewis number was higher than unity, the growth rate was small and the unstable range was narrow, compared with premixed flames at Lewis number of unity, which was because of the weakness of intrinsic instability due to diffusive-thermal effects. As the unburned-gas temperature became higher, the growth rate increased and the unstable range widened. This was because of the increase of the burning velocity of a planar flame. Taking account of radiative heat loss, we obtained small growth rates and narrow unstable range. To study the characteristics of cellular flames generated by intrinsic instability, we superimposed a disturbance with the critical wave number corresponding to the maximum growth rate. The superimposed disturbance evolved, and a cellular flame formed. The burning velocity of a cellular flame normalized by that of a planar flame decreased as the unburned-gas temperature became higher. As the heat loss became larger, the normalized burning velocity of a cellular flame decreased. This indicated that the heat loss inhibited the instability of premixed flames at high Lewis numbers.
format	article
author	Thwe Thwe Aung Toshiyuki KATSUMI Satoshi KADOWAKI
author_facet	Thwe Thwe Aung Toshiyuki KATSUMI Satoshi KADOWAKI
author_sort	Thwe Thwe Aung
title	The effects of unburned-gas temperature on intrinsic instability of premixed flames at high Lewis numbers under the adiabatic and non-adiabatic conditions
title_short	The effects of unburned-gas temperature on intrinsic instability of premixed flames at high Lewis numbers under the adiabatic and non-adiabatic conditions
title_full	The effects of unburned-gas temperature on intrinsic instability of premixed flames at high Lewis numbers under the adiabatic and non-adiabatic conditions
title_fullStr	The effects of unburned-gas temperature on intrinsic instability of premixed flames at high Lewis numbers under the adiabatic and non-adiabatic conditions
title_full_unstemmed	The effects of unburned-gas temperature on intrinsic instability of premixed flames at high Lewis numbers under the adiabatic and non-adiabatic conditions
title_sort	effects of unburned-gas temperature on intrinsic instability of premixed flames at high lewis numbers under the adiabatic and non-adiabatic conditions
publisher	The Japan Society of Mechanical Engineers
publishDate	2017
url	https://doaj.org/article/f147b1d80f9c41f6b33d4252e58ece9f
work_keys_str_mv	AT thwethweaung theeffectsofunburnedgastemperatureonintrinsicinstabilityofpremixedflamesathighlewisnumbersundertheadiabaticandnonadiabaticconditions AT toshiyukikatsumi theeffectsofunburnedgastemperatureonintrinsicinstabilityofpremixedflamesathighlewisnumbersundertheadiabaticandnonadiabaticconditions AT satoshikadowaki theeffectsofunburnedgastemperatureonintrinsicinstabilityofpremixedflamesathighlewisnumbersundertheadiabaticandnonadiabaticconditions AT thwethweaung effectsofunburnedgastemperatureonintrinsicinstabilityofpremixedflamesathighlewisnumbersundertheadiabaticandnonadiabaticconditions AT toshiyukikatsumi effectsofunburnedgastemperatureonintrinsicinstabilityofpremixedflamesathighlewisnumbersundertheadiabaticandnonadiabaticconditions AT satoshikadowaki effectsofunburnedgastemperatureonintrinsicinstabilityofpremixedflamesathighlewisnumbersundertheadiabaticandnonadiabaticconditions
_version_	1718409754539196416

The effects of unburned-gas temperature on intrinsic instability of premixed flames at high Lewis numbers under the adiabatic and non-adiabatic conditions

Ejemplares similares