scholarly journals Extended flamelet model and improved interaction of chemistry and turbulence for modeling partially premixed combustion with a joint PDF method

PAMM ◽  
2007 ◽  
Vol 7 (1) ◽  
pp. 4090019-4090020
Author(s):  
Michael Hegetschweiler ◽  
Patrick Jenny
Keyword(s):  
Premixed Combustion ◽  
Flamelet Model ◽  
Partially Premixed Combustion ◽  
Partially Premixed

Large-Eddy Simulation With a New Flamelet Model for Partially Premixed Combustion in a Gas-Turbine Combustor

2017 ◽  
Author(s):  
Keisuke Tanaka ◽  
Tomonari Sato ◽  
Nobuyuki Oshima ◽  
Jiun Kim ◽  
Yusuke Takahashi ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Diffusion Flame ◽  
Premixed Combustion ◽  
Combustion Model ◽  
Gas Turbine Combustor ◽  
Flamelet Model ◽  
Eddy Simulation ◽  
Partially Premixed Combustion ◽  
Large Eddy ◽  
Partially Premixed

Turbulent combustion flows in the partially premixed combustion field of a dry low-emission gas-turbine combustor were investigated numerically by large-eddy simulation with a 2-scalar flamelet model. Partially premixed combustion was modelled with 2-scalar coupling based on the conservative function of the mixture fraction and the level set function of the premixed flame surface; the governing equations were then used to calculate the gas temperature in the combustion field with flamelet data. A new combustion model was introduced by defining a nondimensional equilibrium temperature to permit the calculation of adiabatic flame temperatures in the combustion field. Furthermore, a conventional G-equation was modified to include spatial gradient terms for the adiabatic flame temperature to facilitate smooth propagation of a burnt-state region in a predominantly diffusion flame. The effect of flame curvature was adjusted by means of an arbitrary parameter in the equation. The simulation results were compared with those from an experiment and a conventional model. Qualitative comparisons of the instantaneous flame properties showed a dramatic improvement in the new combustion model. Moreover, the experimental outlet temperature agreed well with that predicted by the new model. The model can therefore reproduce the propagation of a predominantly diffusion flame in partially premixed combustion.

Effect of Evaporation on the Combustion Behaviour of Kerosene Spray Flame

2010 ◽  
Author(s):  
W. Ahmadi ◽  
M. Chrigui ◽  
A. Sadiki ◽  
G. D. Ngoma
Keyword(s):  
Premixed Combustion ◽  
Spray Combustion ◽  
Liquid Droplets ◽  
Uniform Temperature ◽  
Flamelet Model ◽  
Spray Flame ◽  
Partially Premixed Combustion ◽  
Partially Premixed ◽  
Evaporation Models ◽  
Non Equilibrium

The aim of this paper is to investigate numerically the effects of the evaporation rate on combustion of kerosene sprays in a partially premixed pre-vaporized combustion chamber. The simulations are carried out by means of a Eulerian-Lagrangian approach under consideration of a full two-way coupling. Two different evaporation models (equilibrium and non-equilibrium ansatz) based on the uniform temperature assumption were used. The combustion is described by a BML like model modified for partially premixed combustion description as encountered in LPP (Bray-Moss-Libby Modell) configuration. Dodecane, whose chemistry was described by the flamelet model, was used as a surrogate for kerosene. To isolate the effect of evaporation on spray combustion, liquid droplets have been sprayed at different temperature conditions in a partially premixed pre-vaporized combustor as experimentally investigated in [23]. It turned out that the non-equilibrium performs well and allows achieving an overall agreement with experimental data. With this confidence in place, some parameter studies could be carried out and additional informations, that were not experimentally available, could be extracted to gain insights relevant to understanding the effects under study.

Effects of porous media on partially premixed combustion and heat transfer in meso-scale burners fuelled with ethanol

Energy ◽  
2021 ◽  
pp. 120191
Author(s):  
Xinjian Chen ◽  
Junwei Li ◽  
Dan Zhao ◽  
Muhammad Tahir Rashid ◽  
Xinyuan Zhou ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Premixed Combustion ◽  
Partially Premixed Combustion ◽  
Partially Premixed ◽  
Meso Scale

Effects of Different Type of Gasoline Fuels on Heavy Duty Partially Premixed Combustion

2009 ◽  
Vol 2 (2) ◽  
pp. 71-88 ◽  
Author(s):  
Vittorio Manente ◽  
Bengt Johansson ◽  
Per Tunestal ◽  
William Cannella
Keyword(s):  
Premixed Combustion ◽  
Heavy Duty ◽  
Partially Premixed Combustion ◽  
Partially Premixed

Characterization of Partially Premixed Combustion With Ethanol: EGR Sweeps, Low and Maximum Loads

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Vittorio Manente ◽  
Bengt Johansson ◽  
Pert Tunestal
Keyword(s):  
High Efficiency ◽  
Pressure Rise ◽  
Premixed Combustion ◽  
Maximum Pressure ◽  
Pressure Rise Rate ◽  
Start Of Injection ◽  
Partially Premixed Combustion ◽  
Rise Rate ◽  
Partially Premixed ◽  
Gas Recirculation

Exhaust gas recirculation (EGR) sweeps were performed on ethanol partially premixed combustion (PPC) to show different emission and efficiency trends as compared with diesel PPC. The sweeps showed that when the EGR rate is increased, the efficiency does not diminish, HC trace is flat, and CO is low even with 45% of EGR. NOx exponentially decreases by increasing EGR while soot levels are nearly zero throughout the sweep. The EGR sweeps underlined that at high EGR levels, the pressure rise rate is a concern. To overcome this problem and keep high efficiency and low emissions, a sweep in the timing of the pilot injection and pilot-main ratio was done at ∼16.5 bars gross IMEP. It was found that with a pilot-main ratio of 50:50, and by placing the pilot at −60 with 42% of EGR, NOx and soot are below EURO VI levels; the indicated efficiency is 47% and the maximum pressure rise rate is below 10 bar/CAD. Low load conditions were examined as well. It was found that by placing the start of injection at −35 top dead center, the efficiency is maximized, on the other hand, when the injection is at −25, the emissions are minimized, and the efficiency is only 1.64% lower than its optimum value. The idle test also showed that a certain amount of EGR is needed in order to minimize the pressure rise rate.

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