scholarly journals Structural response of different Lewis number premixed flames interacting with a toroidal vortex

2019 ◽  
Vol 37 (2) ◽  
pp. 1911-1918 ◽  
Author(s):  
Chaimae Bariki ◽  
Fabien Halter ◽  
Fabien Thiesset ◽  
Christian Chauveau ◽  
Iskender Gökalp ◽  
...  
Keyword(s):  
Premixed Flames ◽  
Structural Response ◽  
Lewis Number ◽  
Toroidal Vortex

Numerical Simulation on the Instability of Cylindrically Expanding Premixed Flames With Radiative Heat Loss at Low Lewis Numbers

2011 ◽  
Author(s):  
Takafumi Kusakai ◽  
Satoshi Kadowaki
Keyword(s):  
Heat Loss ◽  
Thermal Instability ◽  
Radiative Heat ◽  
Premixed Flames ◽  
Lewis Number ◽  
Radiative Heat Loss ◽  
Low Gravity ◽  
Gravity Condition ◽  
Quenching Condition ◽  
Reactive Gases

The instability of cylindrically expanding premixed flames with radiative heat loss was studied by two-dimensional unsteady calculations of reactive gases, based on the diffusive-thermal model equation. When the Lewis number was unity, instability phenomena were not observed. When the Lewis number was sufficiently low, on the other hand, cellular-shaped fronts on adiabatic and non-adiabatic cylindrical flames were observed, which was due to diffusive-thermal instability. As radiative heat loss increased, the behavior of cellular fronts became more unstable. This indicated that the radiation promoted the unstable behavior of flame fronts at low Lewis numbers. When radiative heat loss was much large compared with the quenching condition of a planar flame, cylindrical flames were broken up and several small flames appeared. This was in qualitative agreement with the experimental results on the dynamic behavior of lean hydrogen-air premixed flames with radiative heat loss under the low gravity condition. Several small flames appeared on the grounds that large curvature of flame fronts was necessary to keep high temperature against radiative heat loss.

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