Effects of hydrogen addition on entropy generation in ultra-lean counter-flow methane-air premixed combustion

2010 ◽  
Vol 35 (8) ◽  
pp. 3891-3902 ◽  
Author(s):  
Sheng Chen ◽  
Jing Li ◽  
Haifeng Han ◽  
Zhaohui Liu ◽  
Chuguang Zheng
2010 ◽  
Vol 35 (22) ◽  
pp. 12491-12501 ◽  
Author(s):  
Sheng Chen ◽  
Zhaohui Liu ◽  
Jingzhang Liu ◽  
Jing Li ◽  
Lin Wang ◽  
...  

2017 ◽  
Vol 42 (49) ◽  
pp. 29532-29544 ◽  
Author(s):  
Khadidja Safer ◽  
Ahmed Ouadha ◽  
Fouzi Tabet

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shahin Akbari ◽  
Nima Hasanvand ◽  
Sadegh Sadeghi ◽  
Mehdi Bidabadi ◽  
Qingang Xiong

Purpose The widespread usage of magnetic nanoparticles (MNPs) requires their efficient synthesis during combustion process. This study aims to present a mathematical model for the oxidation of MNPs in a counter-flow non-premixed combustion system to produce MNPs, where the key sub-processes during the oxidation reaction are involved. Design/methodology/approach To accurately describe structure of flame and determine distributions of temperature and mass fractions of both reactants and products, equations of energy and mass conservations were solved based on the prevailing assumptions that three regions, i.e. preheating, reaction and oxidizer zones exist. Findings The numerical simulation was first validated against experimental data and characteristics of the combustion process are discussed. Eventually, the influences of crucial parameters such as reactant Lewis numbers, strain rate ratio, particle size, inert gas and thermophoretic force on structure of flame and combustion behavior were examined. The results show that maximum flame temperature can achieve 2,205 K. Replacing nitrogen with argon and helium as carrier gases can increase flame temperature by about 27% and 34%, respectively. Additionally, maximum absolute thermophoretic force was found at approximately 9.6 × 10–8 N. Originality/value To the best of authors’ knowledge, this is the first time to numerically model the preparation of MNPs in a counter-flow non-premixed combustion configuration, which can guide large-scale experimental work in a more effective way.


2006 ◽  
Vol 2006 (0) ◽  
pp. 301-302
Author(s):  
Hideaki Kobayashi ◽  
Hideaki Kaneko ◽  
Soichirou Yata ◽  
Yasuhiro Ogami

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Seyed Ehsan Hosseini ◽  
Ghobad Bagheri ◽  
Mazlan A. Wahid

Biogas has a great potential to be applied for heat and power generation throughout the world due to its availability from various resources. However, one of the most important barriers of biogas utilization development is its low calorific value. In order to increase the performance of biogas in industrial application, hydrogen enriched biogas could be substituted. In this paper a set of numerical simulations were conducted to estimate the variation of entropy generation in hydrogen enriched biogas flames due to hydrogen addition to the fuel. Reynolds Averaged Navier Stokes with a second order turbulence closure and laminar flamelet combustion model was applied to compute energy fields and flow in the flame. It was found that hydrogen enrichment resulted in an augmentation in the entropy generation rate of the biogas conventional flame. Such increase could be attributed to the increase in irreversibilities due to biogas flame temperature rise.


Author(s):  
Baris Yilmaz ◽  
Sibel O¨zdogan ◽  
Iskender Go¨kalp

Hydrogenated premixed methane/air flames under lean conditions are simulated in this study. The computational model of the high pressure chamber setup of Orleans - ICARE (France) has been developed. The k-ε turbulence model with Pope-correction is used for turbulence modeling. The laminar flame properties are computed using GRI-Mech 3.0 mechanism with Chemkin software package. The turbulent flame front statistics are investigated with three premixed combustion models, namely Zimont, Coherent Flame Model (CFM) and modified version of CFM model (MCFM) models. It has been observed that increasing the volumetric percentage of hydrogen in the mixture results in reducing the flame-end position. The flame brush thickness becomes thinner as well. Satisfactory results have been obtained compared to experiments.


Author(s):  
Ségolène Gauthier ◽  
Etienne Lebas ◽  
Dominique Baillis

Within the context of reducing the green house gas emissions, substituting hydrogen for natural gas could have a great environmental impact, but hydrogen has different combustion characteristics than natural gas. This paper reports results of experimental tests of premixed combustion of natural gas-hydrogen mixtures in a porous burner made of open cell metallic foam. The technology of porous radiant burners shows environmental and economical advantages compared to traditional diffusion flame burners. The tests showed that substituting natural gas for hydrogen in a porous burner reduces the pollutant emissions of CO and NOx and the quantity of CO2 produced. For specific powers below 500 kW/m2, the emissions were below the "Blue Angel" label values. But working conditions are limited by hydrogen addition and the equivalence ratio has to be lowered to prevent flashback. The radiant combustion mode is more difficult to obtain with mixtures containing hydrogen and it disappears completely for mixtures with more than 80% vol. hydrogen.


2021 ◽  
Vol 45 ◽  
pp. 101106
Author(s):  
Zhansheng Shi ◽  
Ali Mohammad Ranjbar ◽  
Saeed Shayanseresht ◽  
Khashayar Danesh Narooei ◽  
Mohammad Taghi Fouladvand ◽  
...  

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