Combustion in wavy micro-channels for thermo-photovoltaic applications – Part I: Effects of wavy wall geometry, wall temperature profile and reaction mechanism

Characteristics of H2-enriched CH4O2 diffusion flames in a swirl-stabilized gas turbine combustor: Experimental and numerical study

Experimental and numerical investigation of turbulent isothermal and reacting flows in a non-premixed swirl burner

Frontiers in combustion techniques and burner designs for emissions control and CO2 capture: A review

Combustion and emission characteristics of premixed CNG/H2/CO/CO2 blending synthetic gas flames in a combustor with variable geometric swirl number

Numerical computations of premixed propane flame in a swirl-stabilized burner: Effects of hydrogen enrichment, swirl number and equivalence ratio on flame characteristics

This paper reports a numerical investigation of an atmospheric lean-premixed swirl-stabilized burner. The focus on the flow behavior and flame stability is done at various swirl intensity to better understand the propane turbulent premixed flames. The numerical simulation is carried out using RANS technique with three turbulence closer models Standard k-ε, Realizable k-ε and SST k-ω. This in order to evaluate the performance of these models in the prediction of confined turbulent swirling flows. The turbulence-chemistry interaction scheme is modelled using Finite Rate-Eddy Dissipation model with three step global reaction mechanism. The combustor is operated with air and propane mixture under an atmospheric pressure at a global equivalence ratio of Φ = 0.5. The investigation is done using five different swirl numbers Sn = (0, 0.35, 0.75, 1.05, 1.4), including a validation with the available experimental data. Good agreement is found between RANS results and experimental data, in particular axial and radial velocity profiles, temperature and propane concentration profiles. Results indicate the presence of outer recirculation zone (ORZ) in the inlet burner corner, irrespective of the swirl number. When the swirl number reaches a critical value Sn = 0.75, an inner recirculation zone (IRZ) appears in the center of the burner inlet as a result of vortex-breakdown. Increasing swirl number to an excessive value leads to the propagation of the IRZ upstream the combustion chamber, and consequently the appearance of the flame flashback.

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A Numerical Study of Swirl Effects on the Flow and Flame Dynamics in a Lean Premixed Combustor

Double helical precessing vortex core (PVC) and its interaction with premixed propane flame in a swirl-stabilized burner is studied numerically The model burner is operated under atmospheric pressure, swirl number Sn = 105 and equivalence ratio Φ = 05 Turbulence-chemistry interaction is treated using detached eddy simulation (DES) turbulence model, and finite-rate/eddy dissipation model (FR/EDM) in combination with a 3-step reduced mechanism The flow field is well captured by DES and the premixed flame is well reproduced by FR/EDM Dominant strong vortices are detected in the shear layer of the inner recirculation zone, and secondary outer vortices are found in the combustion chamber corners Temperature and reaction zone maps reveal that the flame is mainly stabilized in the inner shear layer Q-criterion is used to visualize the 3D behavior of the flow It is found that the unsteady flow contains a large-scale coherent PVC with double structure In addition, a co-rotating large-scale second

Detached Eddy Simulation of High Turbulent Swirling Reacting Flow in a Premixed Model Burner

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Numerical investigation of three-dimensional separation control in an axial compressor cascade

An unconfined high turbulent swirling flow is investigated using Detached Eddy Simulation (DES) in a premixed vortex burner. The burner operates with propane-air mixture at high swirl number Sn = 1.05 under atmospheric pressure. In this analysis, the focus of the investigation is the isothermal flow and its expansion at the burner exit. Comparisons of experimental data show that the DES results are capable of predicting the unsteady flow structure and mean velocity profiles. DES results show that the swirling flow is responsible of the formation of a recirculation zone (CRZ) in the center of the burner exit. A helical precessing vortex core (PVC) is detected in the inner shear layer (ISL). Phase-angle analysis of the instantaneous flow field shows the presence of unsteady stagnation points strongly associated with PVC. In addition, phase-angle analysis of the radial profiles of the instantaneous velocities (u, w) is employed to clarify better the instantaneous flow field. The vortex core inside the PVC is analyzed using two slices perpendicular to its axis. It is found that the vortex core is characterized by the limits of its circumferential velocity u(R) and its radius R.

Mokhtar Aouissi

Papers

Numerical computations of premixed propane flame in a swirl-stabilized burner: Effects of hydrogen enrichment, swirl number and equivalence ratio on flame characteristics

A Numerical Study of Swirl Effects on the Flow and Flame Dynamics in a Lean Premixed Combustor

Detached Eddy Simulation of High Turbulent Swirling Reacting Flow in a Premixed Model Burner

Numerical investigation of three-dimensional separation control in an axial compressor cascade

Contribution to study the effect of exhaust gas recirculation EGR on HCCI combustion mode