Large Eddy Simulation of an n-Heptane Spray Flame with Dynamic Adaptive Chemistry under Different Oxygen Concentrations

2015 ◽  
Vol 8 (2) ◽  
pp. 447-454 ◽  
Author(s):  
Lei Zhou ◽  
Zhen Lu ◽  
Zhuyin Ren ◽  
Tianfeng Lu ◽  
K.H Luo
Keyword(s):  
Large Eddy Simulation ◽  
Eddy Simulation ◽  
Spray Flame ◽  
Large Eddy ◽  
Adaptive Chemistry ◽  
Oxygen Concentrations

Large Eddy Simulation of an N-Dodecane Spray Flame Under Different Ambient Oxygen Conditions

2015 ◽  
Author(s):  
Yuanjiang Pei ◽  
Bing Hu ◽  
Sibendu Som
Keyword(s):  
Large Eddy Simulation ◽  
Similarity Index ◽  
Rich Mixture ◽  
Eddy Simulation ◽  
Spray Flame ◽  
Ambient Oxygen ◽  
Large Eddy ◽  
Structure Similarity Index ◽  
Structure Similarity ◽  
Oxygen Concentrations

An n-dodecane spray flame was simulated using a dynamic structure large eddy simulation (LES) model coupled with a detailed chemistry combustion model to understand the ignition processes and the quasi-steady state flame structures. This study focuses on the effect of different ambient oxygen concentrations, 13%, 15% and 21% at an ambient temperature of 900 K and an ambient density of 22.8 kg/m3, which are typical diesel-engine relevant conditions with different levels of exhaust gas recirculation (EGR). The liquid spray was treated with a traditional Lagrangian method. A 103-species skeletal mechanism was used for the n-dodecane chemical kinetic model. It is observed that the main ignitions occur in rich mixture and the flames are thickened around 35 to 40 mm off the spray axis due to the enhanced turbulence induced by the strong recirculation upstream, just behind the head of the flames at different oxygen concentrations. At 1 ms after the start of injection, the soot production is dominated by the broader region of high temperature in rich mixture instead of the stronger oxidation of the high peak temperature. Multiple realizations were performed for the 15% O2 condition to understand the realization to realization variation and to establish best practices for ensemble-averaging diesel spray flames. Two indexes are defined. The structure-similarity index analysis suggests at least 5 realizations are needed to obtain 99% similarity for mixture fraction if the average of 16 realizations are used as the target at 0.8 ms. However, this scenario may be different for different scalars of interest. It is found that 6 realizations would be enough to reach 99% of similarity for temperature, while 8 and 14 realizations are required to achieve 99% similarity for soot and OH mass fraction, respectively. Similar findings are noticed at 1 ms. More realizations are needed for the magnitude-similarity index for the similar level of similarity as the structure-similarity index.

Large-Eddy Simulation of an n-Dodecane Spray Flame Under Different Ambient Oxygen Conditions

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Yuanjiang Pei ◽  
Bing Hu ◽  
Sibendu Som
Keyword(s):  
Large Eddy Simulation ◽  
Similarity Index ◽  
Combustion Model ◽  
Chemical Kinetic Model ◽  
Rich Mixture ◽  
Eddy Simulation ◽  
Spray Flame ◽  
Ambient Oxygen ◽  
Large Eddy ◽  
Oxygen Concentrations

An n-dodecane spray flame was simulated using a dynamic structure large-eddy simulation (LES) model coupled with a detailed chemistry combustion model to understand the ignition processes and the quasi-steady state flame structures. This study focuses on the effect of different ambient oxygen concentrations, 13%, 15%, and 21%, at an ambient temperature of 900 K and an ambient density of 22.8 kg/m3, which are typical diesel-engine relevant conditions with different levels of exhaust gas recirculation (EGR). The liquid spray was treated with a traditional Lagrangian method. A 103-species skeletal mechanism was used for the n-dodecane chemical kinetic model. It is observed that the main ignitions occur in rich mixture, and the flames are thickened around 35–40 mm off the spray axis due to the enhanced turbulence induced by the strong recirculation upstream, just behind the head of the flames at different oxygen concentrations. At 1 ms after the start of injection (SOI), the soot production is dominated by the broader region of high temperature in rich mixture instead of the stronger oxidation of the high peak temperature. Multiple realizations were performed for the 15% O2 condition to understand the realization-to-realization variation and to establish best practices for ensemble-averaging diesel spray flames. Two indexes are defined. The structure-similarity index (SSI) analysis suggests that at least 5 realizations are needed to obtain 99% similarity for mixture fraction if the average of 16 realizations is used as the target at 0.8 ms. However, this scenario may be different for different scalars of interest. It is found that 6 realizations would be enough to reach 99% of similarity for temperature, while 8 and 14 realizations are required to achieve 99% similarity for soot and OH mass fraction, respectively. Similar findings are noticed at 1 ms. More realizations are needed for the magnitude-similarity index (MSI) for the similar level of similarity as the SSI.

Analysis of local extinction of a n-heptane spray flame using large-eddy simulation with tabulated chemistry

2021 ◽  
pp. 111730
Author(s):  
J. Benajes ◽  
J.M. García-Oliver ◽  
J.M. Pastor ◽  
I. Olmeda ◽  
A. Both ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Local Extinction ◽  
Eddy Simulation ◽  
Spray Flame ◽  
Tabulated Chemistry ◽  
Large Eddy

2502 Large Eddy Simulation of Diesel Spray Flame using KIVALES

2007 ◽  
Vol 2007.20 (0) ◽  
pp. 193-194
Author(s):  
Tsukasa HORI ◽  
Hiroshi TANAKA ◽  
Jiro SENDA ◽  
Hajime Fujimoto
Keyword(s):  
Large Eddy Simulation ◽  
Diesel Spray ◽  
Eddy Simulation ◽  
Spray Flame ◽  
Large Eddy

Large Eddy Simulation of a Polydisperse Ethanol Spray Flame

2013 ◽  
Vol 90 (4) ◽  
pp. 813-832 ◽  
Author(s):  
M. Chrigui ◽  
A. R. Masri ◽  
A. Sadiki ◽  
J. Janicka
Keyword(s):  
Large Eddy Simulation ◽  
Eddy Simulation ◽  
Spray Flame ◽  
Large Eddy

scholarly journals Large eddy simulation of a reacting spray flame with multiple realizations under compression ignition engine conditions

2015 ◽  
Vol 162 (12) ◽  
pp. 4442-4455 ◽  
Author(s):  
Yuanjiang Pei ◽  
Sibendu Som ◽  
Eric Pomraning ◽  
Peter K. Senecal ◽  
Scott A. Skeen ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Eddy Simulation ◽  
Spray Flame ◽  
Large Eddy
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