A chemical kinetic investigation of laminar premixed burning characteristics for methane-hydrogen-air mixtures at elevated pressures

2020 ◽  
Vol 111 ◽  
pp. 141-154
Author(s):  
Yongxiang Zhang ◽  
Jianqin Fu ◽  
Jun Shu ◽  
Mingke Xie ◽  
Jingping Liu
Author(s):  
Igor V. Novosselov ◽  
Philip C. Malte

In this paper, the development of an eight-step global chemical kinetic mechanism for methane oxidation with nitric oxide formation in lean-premixed combustion at elevated pressures is described and applied. In particular, the mechanism has been developed for use in computational fluid dynamics (CFD) and chemical reactor network (CRN) simulations of combustion in lean-premixed gas turbine engines. Special attention is focused on the ability of the mechanism to predict NOx and CO exhaust emissions. Applications of the eight-step mechanism are reported in the paper, all for high-pressure, lean-premixed, methane-air (or natural gas-air) combustion. The eight steps of the mechanism are as follows: 1. Oxidation of the methane fuel to CO and H2O. 2. Oxidation of the CO to CO2. 3. Dissociation of the CO2 to CO. 4. Flame NO formation by the Zeldovich and nitrous oxide mechanisms. 5. Flame NO formation by the prompt and NNH mechanisms. 6. Post-flame NO formation by equilibrium H-atom attack on equilibrium N2O. 7. Post-flame NO formation by equilibrium O-atom attack on equilibrium N2O. 8. Post-flame Zeldovich NO formation by equilibrium O-atom attack on N2.


2013 ◽  
Vol 160 (6) ◽  
pp. 995-1011 ◽  
Author(s):  
Alan Kéromnès ◽  
Wayne K. Metcalfe ◽  
Karl A. Heufer ◽  
Nicola Donohoe ◽  
Apurba K. Das ◽  
...  

Author(s):  
John M. Ngugi ◽  
Sandra Richter ◽  
Marina Braun-Unkhoff ◽  
Clemens Naumann ◽  
Uwe Riedel

Abstract Demands of energy will increase worldwide. The use of alternative and renewable energy resources is an attractive option to counteract climate change connected with the burning of fossil fuels. Moreover, improvements in fuel flexibility are a pre-requisite to meet the challenge of a sustainable production of energy in the near future. Within this context, oxygenated molecules, in particular ethers are of high interest because they can be produced renewably. In addition, ethers are promising considerably reduced emissions of particles and soot. In future, ethers might play a role as an alternative fuel (blend) for power generation in gas turbines and in the transport sector. Dimethylether (DME: CH3OCH3) and oxymethylenether (OMEn: CH3O(CH2O)nCH3) are regarded as some of the most promising alternatives to fossil fuels, in particular in compression ignition engines. In this work, we report on a combined experimental and modeling study: The oxidation of mixtures of dimethylether as well as of the simplest oxymethylenether (OME1) was investigated. The focus was put on two fundamental combustion properties: (i) ignition delay times measured in a shock tube device, at ambient and elevated pressures up to 16 bar, for stoichiometric mixtures, and (ii) laminar flame speed data, at ambient and elevated pressures up to 6 bar, determined for OME1. The experimental data base was used for the validation of several detailed chemical-kinetic reaction mechanisms taken from literature. Sensitivity analysis was performed for the two selected targets to allow a better insight into the oxidation network within the envisaged wide parameter range. The findings of the present work will contribute to a better understanding of the combustion of these specific ethers, and to the design and optimization of burners and engines as well.


Author(s):  
Sandra Richter ◽  
Marina Braun-Unkhoff ◽  
Jürgen Herzler ◽  
Torsten Methling ◽  
Clemens Naumann ◽  
...  

Abstract Currently, many research studies are exploring opportunities for the use of novel fuels and of their blends with conventional, i.e. petroleum-based fuels. To pave the way for their acceptance and implementation in the existing energy market, a comprehensive knowledge about their combustion properties is inevitable, among others. Within this context, alcohols, with butanol in particular, are considered as attractive candidates for the needed de-fossilization of the energy sector. In this work, we report on the oxidation of mixtures of n-heptane/i-octane (PRF90, primary reference fuel, a gasoline surrogate) and addition of n-butanol, 20% and 40%, respectively, in a combined experimental and modeling effort. The focus was set on two fundamental combustion properties: (i) Ignition delay times measured in a shock tube, at ambient and elevated pressures, for stoichiometric mixtures, and (ii) Laminar burning velocities, at ambient and elevated pressures. Moreover, two detailed chemical kinetic reaction mechanisms, with an in-house model among them, have been used for investigating and analyzing the combustion of these mixtures. In general, the experimental data agree well with the model predictions of the in-house reaction model, for the temperatures, pressures, and fuel-air ratios studied. Room for improvements is seen for PRF90. The results achieved were also compared to those of n-butanol reported recently; the findings demonstrated clearly the effect of the n-butanol sub model on binary fuel-air mixtures consisting of PRF and n-butanol. From the present work it can be concluded that the addition of n-butanol to gasoline appears to be an attractive alternative fuel for most types of heat engines.


2017 ◽  
Vol 31 (6) ◽  
pp. 6194-6205 ◽  
Author(s):  
Aristotelis M. Zaras ◽  
Milan Szőri ◽  
Sébastien Thion ◽  
Pierre Van Cauwenberghe ◽  
Fiona Deguillaume ◽  
...  

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