Numerical Study on Flame-Front Characteristics of Conical Turbulent Lean Premixed Methane/Air Flames

Yılmaz, Barış; Özdoĝan, Si̇bel; Gökalp, İskender

doi:10.1021/ef8003587

Cited by 8 publications

(4 citation statements)

References 15 publications

(52 reference statements)

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“…The turbulent flame speed increases with the Re λ and at a constant k in the inlet region, in accordance with eq. (10). In all cases tested, U t initially decreases from the turbulence dynamics, as expected, and then suddenly increases within the flame zone.…”

Section: Resultssupporting

confidence: 78%

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

Alhumairi

Ertunç

2018

THERM SCI

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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 λ 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 λ .

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Section: Resultssupporting

confidence: 78%

“…al. [10]. They used CH 4 -air flames with an equivalence ratio, Φ, of 0.6, 0.7, and 0.8, the k-ε turbulence model, and a perforated flame holder to stabilize the flame.…”

Section: Introductionmentioning

confidence: 99%

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

Alhumairi

Ertunç

2018

THERM SCI

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“…It assumes that the flow is fully turbulent, and the effects of molecular viscosity are negligible. The realizable k-ε turbulence model is therefore valid for fully turbulent flows, consistent with the flow characteristics in a typical combustion chamber [17].…”

Section: 20 Modeling Meshing and Boundary Conditionsupporting

confidence: 65%

The Effect of Inlet Air Preheat on CO and NO Production in the Combustion of Diesel in Canister Burner

Jaafar

Omar

2014

Jurnal Teknologi

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The main purpose of this paper is to study the Computational Fluid Dynamics (CFD) prediction on the formation of carbon monoxide and oxide of nitrogen (CO-NO) inside the canister burner with inlet air pre-heating of 100 K and 250 K while varying the swirl angle of the radial swirler. Air swirler adds sufficient swirling to the inlet flow to generate central recirculation region (CRZ) which is necessary for flame stability and fuel air mixing enhancement. Therefore, designing an appropriate air swirler is a challenge to produce stable, efficient and low emission combustion with low pressure losses. A liquid fuel burner system with different radial air swirler with 280 mm inside diameter combustor of 1000 mm length was investigated. Analyses were carried out using four different radial air swirlers having 30°, 40°, 50° and 60° vane angles. The flow behavior was also investigated numerically using CFD solver Ansys Fluent. Overall results show that inlet air preheat quickens the completion of combustion such that the CO and NO production stabilized at a point nearer to fuel injection point, and reduced the CO and NO concentrations due to the combustion.

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“…The turbulent flow field is simulated using the k –ε turbulence model with Pope correction . Several versions of this turbulence model have been evaluated for cold flow . It was concluded that the turbulence model with Pope correction results in better agreement with experiments comparing in-chamber mean and turbulent flow field statistics.…”

Section: Numerical Studiesmentioning

confidence: 99%

Analysis of Turbulent Lean Premixed Methane–Air Flame Statistics at Elevated Pressures

Yılmaz

Gökalp

2017

Energy Fuels

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Combustion takes place within turbulent environments and under pressurized conditions in most industrial applications, for instance, gas turbines and internal combustion engines. The mixing of fuel and oxidizer is enhanced by turbulence, so that combustion will be more efficient. In addition, during combustion, heat is released; therefore, it causes flow instability as a result of gas expansion and high gradients of temperature. The interaction of turbulence and combustion under pressurized conditions may lead to modifications and even disruption of the flame. There are still ongoing studies on the prediction of flame and flow statistics, which are crucial for the stable operation of high-pressure combustion systems. In the present study, the aim is to investigate the influence of elevated pressures on the structure of turbulent premixed methane−air flames, within the range from atmospheric to 0.9 MPa, by numerical modeling and experimental validation. The computations are performed initially for the cold flow field and then for the reactive flow statistics using the Fluent software. For the cold flow case results, it is found that the velocity potential core region extends until three diameters downstream from the burner exit and the decay rate decreases with increasing pressure. However, in the reactive case simulations, the decay in the velocity profiles is not observed as a result of gas expansion through the flame front, similar to the experiments. The turbulent flame front statistics in terms of the flame front location, the flame brush thickness, and the flame surface density (FSD) have been computed. The flame tip location and flame brush thickness are found more downstream and thicker at elevated pressures, respectively. Moreover, both the profiles and peak values of FSD are well-captured for various pressure conditions in computations compared to the measurements.

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Numerical Study on Flame-Front Characteristics of Conical Turbulent Lean Premixed Methane/Air Flames

Cited by 8 publications

References 15 publications

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

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

The Effect of Inlet Air Preheat on CO and NO Production in the Combustion of Diesel in Canister Burner

Analysis of Turbulent Lean Premixed Methane–Air Flame Statistics at Elevated Pressures

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