Numerical Study on Radiant Efficiency of a Porous Burner Under Different Conditions

2018 ◽  
Vol 32 (2) ◽  
pp. 475-482 ◽  
Author(s):  
Hoda Shabani Nejad ◽  
Seyed Abdolreza Gandjalikhan Nassab ◽  
Ebrahim Jahanshahi Javaran
Keyword(s):  
Numerical Study ◽  
Porous Burner ◽  
Radiant Efficiency

Numerical study on the combustion characteristics in a porous-free flame burner for lean mixtures

2019 ◽  
Vol 234 (4) ◽  
pp. 935-945 ◽  
Author(s):  
Seyed Amin Ghorashi ◽  
Seyed Mohammad Hashemi ◽  
Seyed Abdolmehdi Hashemi ◽  
Mahdi Mollamahdi
Keyword(s):  
Porous Medium ◽  
Numerical Study ◽  
Combustion Process ◽  
Experimental Tests ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Numerical Results ◽  
Flame Stability ◽  
Porous Burner ◽  
Flame Burner

The present work implements a numerical simulation to investigate the combustion process in a porous-free flame burner. The non-equilibrium thermal condition is performed, and discretization and solving of the governing equations are conducted in a two-dimensional axisymmetric model. In order to simulate the combustion process, a reduced chemical kinetic mechanism of GRI 3.0, which includes 16 species and 41 reactions, is used. In order to prove the precision of the numerical method, some experimental tests are carried out and the numerical results are in a good agreement with the experimental measurements. The numerical results demonstrate that the porous-free flame burner has a higher flame stability compared to the conventional porous burner and the radiative efficiency of the porous-free flame burner is less than the porous burner. In addition, an increase in thermal conduction of the porous medium leads to an extension in the flame stability. In addition, the results show that with decreasing the pore density of porous medium, the flame stability is extended.

Numerical Study of Combustion Regimes and Heat Radiation of Cylindrical Porous Burner

2016 ◽  
Vol 685 ◽  
pp. 94-98 ◽  
Author(s):  
F.S. Palesskiy
Keyword(s):  
Radiative Heat ◽  
Numerical Study ◽  
Combustion Regime ◽  
Heat Radiation ◽  
Gas Combustion ◽  
Radiative Efficiency ◽  
Porous Burner ◽  
Cylindrical Burner ◽  
Combustion Regimes ◽  
Radiative Characteristics

Temperature and radiative characteristics of different regimes of premixed gas combustion in porous cylindrical burner are investigated numerically. Two-temperature thermal diffusion model with radiative heat transfer and external radiative heat losses described in the framework of Eddington model is applied. It is found that two different combustion regimes can be realized under the same mixture equivalence ratio and flow rate depends on ignition conditions. It is shown that total radiative heat flux from the external surface of the burner and burner’s radiative efficiency strongly depend on the combustion regime.

Numerical study and optimization of a porous burner with annular heat recirculation

2019 ◽  
Vol 157 ◽  
pp. 113741 ◽  
Author(s):  
Fuqiang Song ◽  
Zhi Wen ◽  
Zhiyong Dong ◽  
Enyu Wang ◽  
Xunliang Liu
Keyword(s):  
Numerical Study ◽  
Porous Burner ◽  
Heat Recirculation

Numerical study of the effects of material properties on flame stabilization in a porous burner

2003 ◽  
Vol 134 (4) ◽  
pp. 369-379 ◽  
Author(s):  
Amanda J Barra ◽  
Guillaume Diepvens ◽  
Janet L Ellzey ◽  
Michael R Henneke
Keyword(s):  
Material Properties ◽  
Numerical Study ◽  
Flame Stabilization ◽  
Porous Burner

Experimental and Numerical Study of Premixed Combustion within Porous Media

2012 ◽  
Vol 557-559 ◽  
pp. 1572-1583
Author(s):  
De Bo Li ◽  
Qi Sheng Xu ◽  
Yue Liang Shen ◽  
Zhi Yong Wen ◽  
Ya Ming Liu
Keyword(s):  
Heat Transfer ◽  
Extinction Coefficient ◽  
Numerical Study ◽  
Radiation Heat Transfer ◽  
Convection Heat Transfer ◽  
Flame Velocity ◽  
Convection Heat ◽  
Ceramic Foams ◽  
Porous Burner ◽  
Radiation Extinction

A transient numerical model and experimental study of combustion and heat transfer for methane and oxygen within a two-section porous burner are presented in this paper. It is found that the maximum flame velocity is influenced by the combined effects of extinction coefficient and convection heat transfer coefficient, and that the minimum flame velocities of ceramics with various pore densities have slight differences at different equivalence ratios, while maximum flame velocities have large differences. In addition, the flame velocity depends not only on the interfacial convection heat transfer, but also on the radiation heat transfer of the ceramic foams, which is in accordance with our numerical simulation. Meanwhile, the numerical research in the present paper indicates that radiation extinction coefficient or pores per inch is not the only reason to characterize the heat regeneration effect of ceramic foams.

A NUMERICAL STUDY ON THE SECOND LAW ANALYSIS OF THE FLAME STABILIZATION AND OPTIMIZATION IN A POROUS BURNER

2010 ◽  
Vol 13 (10) ◽  
pp. 875-894 ◽  
Author(s):  
M. Bidi ◽  
M. R. H. Nobari ◽  
M. Saffar Avval ◽  
A. Yarahmadi
Keyword(s):  
Numerical Study ◽  
Flame Stabilization ◽  
Second Law ◽  
Porous Burner ◽  
Second Law Analysis

Numerical Study of the Effects of Volumetric Heat Transfer and Emissivity Coefficient and Porosity on Combustion and Pollutants Formation in a Porous Burner

2008 ◽  
Author(s):  
Siamak Hossainpour ◽  
Bahman Haddadi
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
High Power ◽  
Numerical Study ◽  
The Other ◽  
Porous Burner ◽  
Co Emission ◽  
Solid Temperature ◽  
Emissivity Coefficient ◽  
Good Agreement

In recent years, more attention has been focused on the use of porous materials to enhance the efficiency of combustion systems and to reduce the emission of pollutants. This is because combustion in inert porous media offers an interesting and promising route towards burner with high-power density, high-power dynamic range, and very low emission of pollutants such as NOx and CO. This work reports one-dimensional combustion in a porous burner using three combustion models: GRI 3.0, GRI 2.11, skeletal mechanism. We conclude that GRI 2.11 mechanism has a good agreement with GRI 3.0 and it costs less. At first, we present a numerical study which shows the effects of these models on temperature, species and pollutant emissions. Then, we investigate the effects of volumetric heat transfer and emissivity coefficient and porosity on combustion and pollutions. It was concluded that NO and CO emission depend mainly on the volumetric and emissivity coefficient. When volumetric heat transfer increased, the difference between gas and solid temperature reduced, therewith NO formation noticeably decreased whereas CO emission didn’t change sensible. On the other hand, the flame peak temperature is increased with the reduction of the solid emissivity coefficient. This important conclusion means that NO and CO emission and velocity increases. Also gas and solid temperature increase and vice versa. The other parameter is Porosity. Increasing in porosity of burner resulted in decreasing gas and solid temperature and subsequently NO and CO emission decreased sensible. Porosity has effected on velocity, too. As porosity decreased, velocity increased. Emissivity effects on the rate of heat flux which issue from burner. As the emissivity increased the efficiency of burner arose. Also these parameters have important roles in decreasing the emission especially on No emission because it has more depend on temperature. In addition the resulted gas and solid temperatures were compared with reported measurements of center line temperature in a cylindrical porous burner. The good agreement with experimental observation upholds that the numerical model is a perfect tool to investigate combustion and pollutants formation in porous media.

Numerical study of the flame stability of premixed methane–air combustion in a combined porous-free flame burner

2018 ◽  
Vol 233 (4) ◽  
pp. 530-544 ◽  
Author(s):  
Seyed Mohammad Hashemi ◽  
Seyed Abdolmehdi Hashemi
Keyword(s):  
Equivalence Ratio ◽  
Numerical Study ◽  
Flame Stabilization ◽  
Pollutant Emissions ◽  
Pollutant Emission ◽  
Flame Stability ◽  
Emission Analysis ◽  
Porous Burner ◽  
Flame Burner ◽  
Stability Limits

Premixed methane–air combustion process within a combined porous-free flame burner was investigated numerically in the present study. The burner consisted of a perforated porous ceramic pellet forming combination of submerged and free flame zones. Nonequilibrium thermal condition between the gas and solid phases was implemented and governing equations were solved in a two-dimensional model using finite volume method. Detailed chemistry based on reduced GRI 3.0 mechanism with 41 reaction steps and 16 species including NOx mechanisms was utilized to simulate the combustion processes and pollutant emissions. In order to investigate the validation of the implemented numerical model, the burner was manufactured and tested. The predicted results were consistent with the experimental data. Comparison of the combined porous-free flame burner with porous burner showed that the flame stability limits of the combined burner were higher than those of porous burner. Multimode heat transfer within the porous medium was perused and the effect of heat recirculation on the flame stabilization was discussed. Investigation of the effect of pore density on the flame stabilization showed that the lower pore densities were desirable in order to improve the flame stability limits. Pollutant emission analysis proved that the NO concentration increased with increasing the equivalence ratio while the minimum quantity of CO concentration was evaluated at an equivalence ratio of 0.6.

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