Open AccessLES-PDF Modeling of Blowout Analysis in Slit Bluff-Body Stabilized Flames
Author(s) -
Xiao Liu,
Hongtao Zheng,
Jian Yang,
Yajun Li
Publication year - 2015
Publication title -
international journal of spray and combustion dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 16
eISSN - 1756-8285
pISSN - 1756-8277
DOI - 10.1260/1756-8277.7.2.131
Subject(s) - vortex shedding , turbulence , bluff , mechanics , physics , large eddy simulation , vortex , combustion , flow (mathematics) , inlet , work (physics) , meteorology , thermodynamics , geology , reynolds number , chemistry , organic chemistry , geomorphology
This work presents a numerical study of a premixed turbulent combustion behind slit bluff-body by Large Eddy Simulation (LES) and Composition PDF Transport (C-PDF) with detailed mechanism, the main focus is placed on the blowout analysis. Different flow and combustion structure is observed, two different sizes recirculation zones (RZ) are formed because of the gap flow; a V shape high temperature area exists behind slit bluff-body as a pilot flame. The blowout process was analyzed by time sequence of instantaneous temperature fields. It can be seen as the process of two small bluff-bodies strongly coupled by the gap flow. Both RZs began to shed a von Karman (vK) vortices street and the large vortex shedding from big RZ will swallow the small one from small RZ and form a larger vortex. Localized extinction exists both along the shear layer and behind the gap. The small RZ will blowout firstly once the shear layer and gap extinction meet, and then will the big RZ. The predicted blowout limits indicate that the blowout limit can be significantly improved at an optimal ratio of slit width. In addition, the influence of inlet velocity and temperature was predicted, the results show that enough energy produced by the V shape high temperature area to sustain the flame is the most important factor on the performance of the blowout