Asymptotic treatment of premixed flame structure with diffusion.

AIAA Journal ◽  
1967 ◽  
Vol 5 (4) ◽  
pp. 808-809 ◽  
Author(s):  
FRANCIS E. FENDELL
Keyword(s):  
Flame Structure ◽  
Premixed Flame

POD Scale Analysis of Turbulent Premixed Flame Structure at Elevated Pressures

2019 ◽  
pp. 1-23
Author(s):  
Yaohui Nie ◽  
Jinhua Wang ◽  
Shilong Guo ◽  
Weijie Zhang ◽  
Wu Jin ◽  
...  
Keyword(s):  
Flame Structure ◽  
Premixed Flame ◽  
Scale Analysis ◽  
Turbulent Premixed Flame ◽  
Elevated Pressures ◽  
Turbulent Premixed

Analysis of turbulent premixed flame structure using simultaneous PIV-OH PLIF

2004 ◽  
Vol 7 (1) ◽  
pp. 43-54 ◽  
Author(s):  
Y. Cho ◽  
J. -H. Kim ◽  
T Cho ◽  
I Moon ◽  
Y Yoon ◽  
...  
Keyword(s):  
Flame Structure ◽  
Premixed Flame ◽  
Turbulent Premixed Flame ◽  
Turbulent Premixed

H2/CO/air premixed and partially premixed flame structure at different pressures based on reaction limit analysis

2018 ◽  
Vol 63 (19) ◽  
pp. 1260-1266 ◽  
Author(s):  
Zaigang Liu ◽  
Wenjun Kong ◽  
Jean-Louis Consalvi ◽  
Wenhu Han
Keyword(s):  
Limit Analysis ◽  
Flame Structure ◽  
Premixed Flame ◽  
Partially Premixed ◽  
Partially Premixed Flame

Fuel wall film effects on premixed flame propagation, quenching and emission

2018 ◽  
Vol 21 (6) ◽  
pp. 1055-1066 ◽  
Author(s):  
Mingyuan Tao ◽  
Haiwen Ge ◽  
Brad VanDerWege ◽  
Peng Zhao
Keyword(s):  
Flame Propagation ◽  
Direct Injection ◽  
Flame Structure ◽  
Three Dimensional ◽  
Premixed Flame ◽  
Practical Significance ◽  
Detailed Chemistry ◽  
Rich Mixture ◽  
Wall Film ◽  
Flame Quenching

The formation of fuel wall film is a primary cause for efficiency loss and emissions of unburnt hydrocarbons and particulate matters in direct injection engines, especially during cold start. When a premixed flame propagates toward a wall film of liquid fuel, flame structure and propagation could be fundamentally affected by the vaporization flux and the induced thermal and concentration stratifications. It is, therefore, of both fundamental and practical significance to investigate the consequent effect of a wall film on flame quenching. In this work, the interaction of a laminar premixed flame and a fuel wall film has been studied based on one-dimensional direct numerical simulation with detailed chemistry and transport. The mass and energy balance at the wall film interface have been implemented as boundary condition to resolve vaporization. Parametric studies are further conducted with various initial temperatures of 600–800 K, pressures of 7–15 atm, fuel film and wall temperatures of 300–400 K. By comparing the cases with an isothermal dry wall, it is found that the existence of a wall film always promotes flame quenching and causes more emissions. Although quenching distance can vary significantly among conditions, the local equivalence ratio at quenching is largely constant, suggesting the dominant effects of rich mixture and rich flammability limit. By further comparing constant volume and constant pressure conditions, it is observed that pressure and boiling point variation dominate the vaporization boundary layer development and flame quenching, which further suggests that increased pressure during compression stroke in engines can significantly suppress film vaporization. Emissions of unburnt hydrocarbon, soot precursor and low-temperature products before and after flame quenching are also investigated in detail. The results lead to useful insights on the interaction of flame propagation and wall film in well-controlled simplified configurations and shed light on the development of wall film models in three-dimensional in-cylinder combustion simulation.

A comparison of turbulent dimethyl ether and methane non-premixed flame structure

2013 ◽  
Vol 34 (1) ◽  
pp. 1447-1454 ◽  
Author(s):  
Kathryn N. Gabet ◽  
Han Shen ◽  
Randy A. Patton ◽  
Frederik Fuest ◽  
Jeffrey A. Sutton
Keyword(s):  
Dimethyl Ether ◽  
Flame Structure ◽  
Premixed Flame

The Structure of Two-Stage Counterflow n-Heptane-Air Flames

2000 ◽  
Author(s):  
S. K. Aggarwal ◽  
H. S. Xue
Keyword(s):  
Strain Rate ◽  
Reaction Zone ◽  
Equivalence Ratio ◽  
Flame Structure ◽  
Premixed Combustion ◽  
Premixed Flame ◽  
Partially Premixed Combustion ◽  
Reaction Zones ◽  
Partially Premixed ◽  
Partially Premixed Flame

Partially premixed flames are formed by mixing air (in less than stoichiometric amounts) into the fuel stream prior to the reaction zone, where additional air is available for complete combustion. Such flames can occur in both laboratory and practical combustion systems. In advanced gas turbine combustor designs, such as a lean direct injection (LDI) combustor, partially premixed combustion represents an impotent mode of burning. Spray combustion often involves partially premixed combustion due to the locally fuel vapor-rich regions. In the present study, the detailed structure of n-heptane/air partially premixed flame in a counterflow configuration is investigated. The flame is computed by employing the Oppdif code and a detailed reaction mechanism consisting of 275 elementary reactions and 41 species. The partially premixed flame structure is characterized by two-stage burning or two distinct but synergistically coupled reaction zones, a rich premixed zone on the fuel side and a ‘nonpremixed zone on the air side. The fuel is completely consumed in the premixed zone with ethylene and acetylene being the major intermediate species. The reactions involving the consumption of these species are found to be the key rate-limiting reactions that characterize interactions between the two reaction zones, and determine the overall fuel consumption rate. The flame response to the variations in equivalence ratio and strain rate is examined. Increasing equivalence ratio and/or strain rate to a critical value leads to merging of the two reaction zones. The equivalence ratio variation affects the rich premixed reaction zone, while the variation in strain rate predominantly affects the nonpremixed reaction zone. The flame structure is also characterized in terms of a modified mixture fraction (conserved scalar), and laminar flamelet profiles are provided.

Sign in / Sign up

Export Citation Format

Share Document