scholarly journals Extension of the turbulent flame speed closure model to ignition in multiphase flows

2013 ◽  
Vol 160 (2) ◽  
pp. 351-365 ◽  
Author(s):  
Jan M. Boyde ◽  
Patrick C. Le Clercq ◽  
Massimiliano Di Domenico ◽  
Manfred Aigner
Keyword(s):  
Multiphase Flows ◽  
Turbulent Flame ◽  
Flame Speed ◽  
Closure Model ◽  
Turbulent Flame Speed

Modelling of a Premixed Swirl-stabilized Flame Using a Turbulent Flame Speed Closure Model in LES

2008 ◽  
Vol 82 (4) ◽  
pp. 537-551 ◽  
Author(s):  
F. Zhang ◽  
P. Habisreuther ◽  
M. Hettel ◽  
H. Bockhorn
Keyword(s):  
Turbulent Flame ◽  
Flame Speed ◽  
Closure Model ◽  
Turbulent Flame Speed

scholarly journals Active-grid turbulence effect on the topology and the flame location of a lean premixed combustion

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2425-2438 ◽  
Author(s):  
Mohammed Alhumairi ◽  
Özgür Ertunç
Keyword(s):  
Turbulent Combustion ◽  
Turbulent Flame ◽  
Jet Flow ◽  
Flame Speed ◽  
Premixed Combustion ◽  
Grid Turbulence ◽  
Closure Model ◽  
Lean Premixed Combustion ◽  
Turbulent Flame Speed ◽  
Combustion Models

Lean premixed combustion under the influence of active-grid turbulence was computationally investigated, and the results were compared with experimental data. The experiments were carried out to generate a premixed flame at a thermal load of 9 kW from a single jet flow combustor. Turbulent combustion models, such as the coherent flame model and turbulent flame speed closure model were implemented for the simulations performed under different turbulent flow conditions, which were specified by the Reynolds number based on Taylor?s microscale, the dissipation rate of turbulence, and turbulent kinetic energy. This study shows that the applied turbulent combustion models differently predict the flame topology and location. However, similar to the experiments, simulations with both models revealed that the flame moves toward the inlet when turbulence becomes strong at the inlet, that is, when Re? at the inlet increases. The results indicated that the flame topology and location in the coherent flame model were more sensitive to turbulence than those in the turbulent flame speed closure model. The flame location behavior on the jet flow combustor significantly changed with the increase of Re?.

scholarly journals Numerical Investigation of Pressure Influence on the Confined Turbulent Boundary Layer Flashback Process

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 146 ◽  
Author(s):  
Aaron Endres ◽  
Thomas Sattelmayer
Keyword(s):  
Boundary Layer ◽  
Gas Turbines ◽  
Separation Zone ◽  
Turbulent Flame ◽  
Pressure Rise ◽  
Flame Speed ◽  
Zone Size ◽  
Detailed Chemical Kinetics ◽  
Turbulent Flame Speed ◽  
Quenching Distance

Boundary layer flashback from the combustion chamber into the premixing section is a threat associated with the premixed combustion of hydrogen-containing fuels in gas turbines. In this study, the effect of pressure on the confined flashback behaviour of hydrogen-air flames was investigated numerically. This was done by means of large eddy simulations with finite rate chemistry as well as detailed chemical kinetics and diffusion models at pressures between 0 . 5 and 3 . It was found that the flashback propensity increases with increasing pressure. The separation zone size and the turbulent flame speed at flashback conditions decrease with increasing pressure, which decreases flashback propensity. At the same time the quenching distance decreases with increasing pressure, which increases flashback propensity. It is not possible to predict the occurrence of boundary layer flashback based on the turbulent flame speed or the ratio of separation zone size to quenching distance alone. Instead the interaction of all effects has to be accounted for when modelling boundary layer flashback. It was further found that the pressure rise ahead of the flame cannot be approximated by one-dimensional analyses and that the assumptions of the boundary layer theory are not satisfied during confined boundary layer flashback.

Sign in / Sign up

Export Citation Format

Share Document