Large eddy simulation of a pulverized coal jet flame ignited by a preheated gas flow

2011 ◽  
Vol 33 (2) ◽  
pp. 1771-1778 ◽  
Author(s):  
Kenji Yamamoto ◽  
Tomoya Murota ◽  
Teruyuki Okazaki ◽  
Masayuki Taniguchi
Keyword(s):  
Large Eddy Simulation ◽  
Gas Flow ◽  
Pulverized Coal ◽  
Jet Flame ◽  
Eddy Simulation ◽  
Large Eddy

Large Eddy Simulation of Pulverized Coal Jet Combustion and Flame Propagation

2020 ◽  
Author(s):  
Ying Gui
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Combustion ◽  
Gas Flow ◽  
Combustion Process ◽  
Reaction Model ◽  
Pulverized Coal ◽  
Jet Flame ◽  
Eddy Simulation ◽  
Eddy Viscosity Model ◽  
Large Eddy

Abstract The characteristics of a pulverized coal jet flame ignited by a preheated gas flow are modeled with large eddy simulation (LES) method. An open-source computational fluid dynamics (CFD) code –OpenFOAM (open field operation and manipulation) is applied to predict the instantaneous temperature, pressure, vortices and species mass fraction of the whole combustion process. The sub-grid scale (SGS) turbulence and combustion models based on the one-equation eddy-viscosity model and the kinetic-diffusion limited rate surface reaction model are used in the modeling process. Jet combustions with different inlet velocities are simulated to get an optimal value under the condition that a good combustion kinetic filed can be established. In order to prove the advantages of LES on the predictions of turbulent combustion, Reynolds-averaged Navier-Stokes (RANS) simulation has been performed and compared with the results of LES. The results suggest that LES can predict the instantaneous values of turbulent combustion while RANS can only get average effects. The ability of LES to capture the high and low values of temperature and species concentrations is better, and it can capture the flame centre and predict the recirculation flows more accurately than RANS. Furthermore, the effect of coal particle diameters on the flame characteristics is also investigated by LES. It has been observed that the region of high temperature is wider, the flame center is closer to the nozzle exit, and the local temperature is higher for smaller particles. The results also show that the combustion is more intensive and complete for smaller particles, which are coincident with the combustion theory.

scholarly journals Large-eddy simulation of pulverized coal jet flame – Effect of oxygen concentration on NOx formation

Fuel ◽  
2015 ◽  
Vol 142 ◽  
pp. 152-163 ◽  
Author(s):  
Masaya Muto ◽  
Hiroaki Watanabe ◽  
Ryoichi Kurose ◽  
Satoru Komori ◽  
Saravanan Balusamy ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Oxygen Concentration ◽  
Pulverized Coal ◽  
Nox Formation ◽  
Jet Flame ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Effect Of Oxygen

118 Large-Eddy Simulation of Pulverized Coal Swirl Jet Flame : Effect of Oxygen Concentration on NOx generation

2014 ◽  
Vol 2014.89 (0) ◽  
pp. _1-18_
Author(s):  
Masaya MUTO ◽  
Hiroaki WATANABE ◽  
Ryoichi KUROSE ◽  
Satoru KOMORI ◽  
Saravanan BALUSAMY ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Oxygen Concentration ◽  
Pulverized Coal ◽  
Jet Flame ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Effect Of Oxygen

Large-Eddy Simulation of Alkali Metal Reacting Dynamics in a Preheated Pulverized-Coal Jet Flame Using Tabulated Chemistry

2017 ◽  
Author(s):  
Kaidi Wan ◽  
Zhihua Wang ◽  
Luc Vervisch ◽  
Jun Xia ◽  
Yingzu Liu ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Alkali Metal ◽  
Coal Combustion ◽  
Pulverized Coal ◽  
Biomass Combustion ◽  
Pulverized Coal Combustion ◽  
Jet Flame ◽  
Eddy Simulation ◽  
Atomic Sodium ◽  
Large Eddy

This paper proposed an approach to modeling alkali metal reacting dynamics in turbulent pulverized-coal combustion (PCC) using tabulated sodium chemistry. With tabulation, detailed sodium chemistry can be incorporated in large-eddy simulation (LES), but the expenses of solving stiff Arrhenius equations can be avoided. The sodium release rate from a pulverized-coal particle is assumed to be proportional to the pyrolysis rate, as a simplification. The chemical forms of released sodium is assumed to be atomic sodium Na, because atomic sodium is predicted to be the favoured species in a flame environment. A detailed sodium chemistry mechanism including 5 sodium species, i.e., Na, NaO, NaO2, NaOH and Na2O2H2, and 24 elementary reactions is tabulated. The sodium chemistry table contains four coordinates, i.e., the equivalence ratio, the mass fraction of the sodium element, the gas-phase temperature, and the progress variable. Apart from the reactions of sodium species, hydrocarbon volatile combustion has been modeled by a partially stirred reactor concept. Since the magnitude of sodium species is very small, i.e., at the ppm level, and the reactions of sodium species are slower than volatile combustion, one-way coupling is used for the interaction between the sodium reactions and volatile combustion, i.e., the former having no influence on the latter. A verification study has been performed to compare the predictions on sodium species evolutions in zero-dimensional simulations using the chemistry table against directly using the detailed sodium mechanism under various initial conditions, and their agreement is always good. The PCC-LES solver used in the present study is validated on a pulverized-coal jet flame ignited by a preheated gas flow. Good agreements between the experimental measurements and the LES results have been achieved on gas temperature, coal burnout and lift-off height. Finally, the sodium chemistry table is incorporated into the LES solver to model sodium reacting dynamics in turbulent pulverized-coal combustion. Properties of Loy Yang brown coal, for which sodium data are available, are used. Characteristics of the reacting dynamics of the 5 sodium species in a pulverized-coal jet flame are then obtained. The results show that Na and NaOH are the two major sodium species in the pulverized-coal jet flame. Na, the atomic sodium, has a high concentration in fuel-rich regions; while the highest NaOH concentration is found in regions close to the stoichiometric condition. It should be pointed out that the proposed chemistry tabulation approach can be extended to modeling potassium reacting dynamics in turbulent multiphase biomass combustion. (CSPE)

Large eddy simulation of a supersonic lifted jet flame in the high-enthalpy coflows

2021 ◽  
Author(s):  
Chaoyang Liu ◽  
Ning Wang ◽  
Kai Yang ◽  
Dongpeng Jia ◽  
Yu Pan
Keyword(s):  
Large Eddy Simulation ◽  
Jet Flame ◽  
High Enthalpy ◽  
Eddy Simulation ◽  
Large Eddy
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