Turbulent Flame Speed Closure Model: Further Development and Implementation for 3-D Simulation of Combustion in SI Engine

The turbulent lean premixed combustion simulation is implemented in 4- stroke spark ignition (SI) engine. The Turbulent Flame speed Closure model (TFC) is used in different turbulent flow conditions. The model is tested for a variety of flame configurations such as turbulent flame speed, the heat release from the combustion and turbulent kinetic energy in the radial direction of the cylinder at 15.5 mm below the top dead center TDC point. The simulation performs in the three cases of the (intake / exhaust) valve timing. The exhaust valve case is an essential leverage on the turbulent flame specification. The combustion period is very important factor in SI engine which is controlled especially by the turbulent flame speed. The turbulent flame speed and heat transfer is ascendant less than 10 % and 3% in case of intake and exhaust valves are closed respectively. Moreover, the results show that the brake power enhances less than 4% and more than 40% with increase fuel temperature 60 K and engine speed 3000 rpm respectively.

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Evaluation of the applicability of Zimont's turbulent flame speed closure model to an octane fueled engine with moderate level of turbulent intensity

2017 Moratuwa Engineering Research Conference (MERCon) ◽

10.1109/mercon.2017.7980483 ◽

2017 ◽

Author(s):

J.K.L. Eranga

Keyword(s):

Turbulent Flame ◽

Flame Speed ◽

Moderate Level ◽

Turbulent Intensity ◽

Closure Model ◽

Turbulent Flame Speed

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

Thermal Science ◽

10.2298/tsci170503100a ◽

2018 ◽

Vol 22 (6 Part A) ◽

pp. 2425-2438 ◽

Cited By ~ 1

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?.

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

Fluids ◽

10.3390/fluids4030146 ◽

2019 ◽

Vol 4 (3) ◽

pp. 146 ◽

Cited By ~ 2

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.

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