Numerical Analysis of Flame Characteristics and Stability for Conical Nozzle Burner

Abstract

The stability and the mean structure of methane partially premixed conical burner flames was investigated numerically using ANSYS Fluent. The study presents and discusses the stability curves of the partially premixed flame and maps the mean flame structure based on contours of mass fraction of O2, CO and temperature. From the data obtained, it can be concluded that both premixed and non-premixed flames are less stable than the partially premixed flames. An optimum level of partially premixing was found and the flames beyond this threshold were found to be less stable. This optimum level was found, when the ratio of the mixing length to the nozzle diameter is equal to 5. At this specific degree of partially premixing, the flame exhibited triple interaction reaction zones. It was found that with an increase of the angle of the cone of the burner, the air entrainment increases which, in turns breaks the stabilization core and hence cause a reduction in the flame stability limit. The main role of the cone is to provide a protection from the surrounding environment at early phase of the reaction near the jet exit where turbulence with high intensity was observed.

Numerical study of the injection conditions effect on the behavior of hydrogen-air diffusion flame

“…The prediction of the aerothermochemical variables of fluid flow is available by solving the Reynolds Average Navier-Stokes equations (RANS), energy and transport of chemical species [21][22][23]. Turbulence is described by K-ɛ model [17][18][19][20][21][22][23][24][25][26]. This is useful in order to correct an overestimation due to radial expansion of the round jet coming from the ring injector [27,28].…”

“…The aim of this investigation is to use Computational Fluid Dynamics approach as an effective computer based simulation tool to study and develop the hydrogen combustion processes [18]. Several constraints can get involved to make an experiments of combustion not recommended where, these ones may cause a harmful danger to the entourage [2,5].…”

“…For the hydrogen combustion case is even worse, due to the characteristics of the hydrogen substance itself. This is the reason why it is preferred to use a high fidelity computation systems [18][19][20]. Computational fluid dynamics and modeling techniques are becoming increasingly important tools to assess the impact of hydrogen combustion in the operating burners [2,16].…”

“…However, the complete description of particle trajectories, chemistry reactions and energy production is needed. This numerical investigation is about making a numerical approach to comprehend how injection conditions can affect the hydrogen flame behavior which is dependent to the same geometric configuration [5,18].…”

An Integrated Model to Study the Effects of Operational Parameters on the Performance and Pollutant Emissions in a Utility Boiler

“…In this study, a standard k-ε model was used to take into account the turbulence in the furnace. This turbulence model seems to be sufficient for modeling the flow inside an industrial furnace or burner, as it was used satisfactory in many articles [5,6,7,10,11,14,18,33,36,37] and had some strengths in a comparison between turbulence models in CFD modeling of burners [38]. For combustion, the eddy dissipation model was employed.…”