scholarly journals Numerical Study on Flame Stabilization Mechanism of a multi-jet burner with LES Flamelet Approach

2016 ◽  
Author(s):  
Yihao Tang ◽  
Heeseok Koo ◽  
Christopher Lietz ◽  
Venkatramanan Raman
Keyword(s):  
Numerical Study ◽  
Flame Stabilization ◽  
Stabilization Mechanism

Numerical investigation of cold flow over regular and wavy V-gutters

2019 ◽  
Vol 233 (15) ◽  
pp. 5837-5855
Author(s):  
Mohammadreza Mollaei ◽  
Hojat Ghassemi
Keyword(s):  
Turbulence Modeling ◽  
Numerical Study ◽  
Three Dimensional ◽  
Flame Stabilization ◽  
Recirculation Region ◽  
Cold Flow ◽  
Static Pressure Distribution ◽  
Recirculation Length ◽  
Volume Method ◽  
Phase Angles

In this paper, the numerical study of cold flow over two types of regular and wavy V-gutter flame holders has been presented. The edges of the V-gutter, which are smooth in the regular case, are shaped in a sinusoidal form with different phase angles on upper and lower edges. The three-dimensional numerical analysis has been performed using the finite volume method and the renormalization group k–ɛ model has been used for turbulence modeling. The results were compared and validated by an existing experimental work based on the particle image velocimetry method. This study provided the fluid flow structure behind the V-gutter, the dimensions of the recirculation region, the behavior of vortex shedding phenomenon, and the static pressure distribution in the wake area. According to the results, the recirculation length for the sinusoidal case with 90 ° of the phase difference is the largest compared with the other cases, which increases the mass flow rate of the fresh unburnt mixture into the recirculation region and improves flame stability. The results also show that the 90 ° wavy V-gutter case has the lowest pressure drop in the wake region, which reduces the drag coefficient against the main flow. The values of the Strouhal number are approximately the same and equal to 0.27 for both cases (the regular and the 90 ° cases). Therefore, it is concluded that the 90 ° wavy V-gutter shows better performance than the regular V-gutter in flame stabilization.

Slotted Channel As A Gasdynamical Source Of Ignition And Flame Stabilization In The Supersonic Combustion Chamber

2016 ◽  
Vol 11 (1) ◽  
pp. 34-44
Author(s):  
Marat Goldfeld ◽  
Yuliya Zakharova ◽  
Alexey Starov ◽  
Konstantin Timofeev
Keyword(s):  
High Temperature ◽  
Stokes Equations ◽  
Numerical Study ◽  
Flame Stabilization ◽  
Supersonic Combustion ◽  
Navier Stokes ◽  
Experimental Investigations ◽  
Navier Stokes Equations ◽  
Exit Nozzle ◽  
Sst Turbulence Model

The original scheme of flame stabilization in the channel at close to cocurrent fuel supply for the fuel combustion at a high supersonic speed has been designed. Such solution provides high temperature of a stream in a zone of fuel-air mixture formation. Computational and experimental investigations of self-ignition and combustion of hydrogen were carried out in the model of combustor chamber with slotted channel (gasdynamical source of ignition) at Mach numbers 3.7 and 5.8 at the entrance. Tests have been performed in hot-shot wind tunnel IT-302M of ITAM SB RAS in a mode of the attached pipe. Numerical study has been performed on the basis of solving the full averaged Navier-Stokes equations, supplemented k-Q SST turbulence model. Configuration of the slotted channel has been designed with two variants of exit nozzle: with and without geometrical throat. It has been established that at the channel entrance two vortexes with high temperature have been appeared. Temperature has been keeping high in the channel with geometrical throat and at blocking of the slotted channel without throat. It was found that uniform subsonic stream in the channel with geometrical throat has been realized. The stream in the slotted channel without geometrical throat keeps supersonic but Mach number was lower than in the main channel. The structure of the flow at the slotted channel exit is significantly differs for this both cases.

scholarly journals A numerical study of the effect of nozzle diameter on diesel combustion ignition and flame stabilization

2019 ◽  
Vol 21 (1) ◽  
pp. 101-121 ◽  
Author(s):  
Jose M Desantes ◽  
Jose M Garcia-Oliver ◽  
Ricardo Novella ◽  
Leonardo Pachano
Keyword(s):  
Residence Time ◽  
Numerical Study ◽  
Local Heat ◽  
Flame Stabilization ◽  
Nozzle Diameter ◽  
Combustion Model ◽  
Diesel Combustion ◽  
Mixing Rate ◽  
Auto Ignition ◽  
Thermodynamic Conditions

The role of nozzle diameter on diesel combustion is studied by performing computational fluid dynamics calculations of Spray A and Spray D from the Engine Combustion Network. These are well-characterized single-hole sprays in a quiescent environment chamber with thermodynamic conditions representative of modern diesel engines. First, the inert spray evolution is described with the inclusion of the concept of mixing trajectories and local residence time into the analysis. Such concepts enable the quantification of the mixing rate, showing that it decreases with the increase in nozzle diameter. In a second step, the reacting spray evolution is studied focusing on the local heat release rate distribution during the auto-ignition sequence and the quasi-steady state. The capability of a well-mixed-based and a flamelet-based combustion model to predict diesel combustion is also assessed. On one hand, results show that turbulence–chemistry interaction has a profound effect on the description of the reacting spray evolution. On the other hand, the mixing rate, characterized in terms of the local residence time, drives the main changes introduced by the increase of the nozzle diameter when comparing Spray A and Spray D.

scholarly journals Experimental and Numerical Study of Swirling Diffusion Flame Provided by a Coaxial Burner: Effect of Inlet Velocity Ratio

Fluids ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 159
Author(s):  
Sawssen Chakchak ◽  
Ammar Hidouri ◽  
Hajar Zaidaoui ◽  
Mouldi Chrigui ◽  
Toufik Boushaki
Keyword(s):  
Diffusion Flame ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Flow Behavior ◽  
Velocity Ratio ◽  
Flame Stabilization ◽  
Stereoscopic Particle Image Velocimetry ◽  
Pollutant Emission ◽  
Combustion Model ◽  
Inlet Velocity

This paper reports an experimental and numerical investigation of a methane-air diffusion flame stabilized over a swirler coaxial burner. The burner configuration consists of two tubes with a swirler placed in the annular part. The passage of the oxidant is ensured by the annular tube; however, the fuel is injected by the central jet through eight holes across the oxidizer flow. The experiments were conducted in a combustion chamber of 25 kW power and 48 × 48 × 100 cm3 dimensions. Numerical flow fields were compared with stereoscopic particle image velocimetry (stereo-PIV) fields for non-reacting and reacting cases. The turbulence was captured using the Reynolds averaged Navier-Stokes (RANS) approach, associated with the eddy dissipation combustion model (EDM) to resolve the turbulence/chemistry interaction. The simulations were performed using the Fluent CFD (Computational Fluid Dynamic) code. Comparison of the computed results and the experimental data showed that the RANS results were capable of predicting the swirling flow. The effect of the inlet velocity ratio on dynamic flow behavior, temperature distribution, species mass fraction and the pollutant emission were numerically studied. The results showed that the radial injection of fuel induces a partial premixing between reactants, which affects the flame behavior, in particular the flame stabilization. The increase in the velocity ratio (Rv) improves the turbulence and subsequently ameliorates the mixing. CO emissions caused by the temperature variation are also decreased due to the improvement of the inlet velocity ratio.

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