Heat release rate estimation in laminar premixed flames using laser-induced fluorescence of CH2O and H-atom

Mulla, Irfan; Dowlut, A.; Hussain, Taaha; Nikolaou, Zacharias M.; Chakravarthy, Satyanarayanan R.; Swaminathan, Nedunchezhian; Balachandran, Ramanarayanan

doi:10.1016/j.combustflame.2015.12.023

Cited by 51 publications

(21 citation statements)

References 35 publications

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“…The example of flame extinction will be discussed in greater detail later when we compare Large-Eddy Simulations used for finite-rate kinetic effects against local flame extinction inferred from fast OH-PLIF, which has allowed very thorough validation of the sub-grid turbulent combustion model. Recent developments in PLIF include the imaging of NO [61], soot precursors like Poly-cyclic Aromatic Hydrocarbons (PAH) [62], H atom [63] and HCO [64]. The technical difficulties, resolution issues, lasers and cameras needed are discussed in the original papers.…”

Section: Experimental Diagnosticsmentioning

confidence: 99%

Turbulent Combustion Modelling and Experiments: Recent Trends and Developments

Giusti

Mastorakos

2019

Flow Turbulence Combust

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The development of better laser-based experimental methods and the fast rise in computer power has created an unprecedented shift in turbulent combustion research. The range of species and quantities measured and the advent of kHz-level planar diagnostics are now providing great insights in important phenomena and applications such as local and global extinction, pollutants, and spray combustion that were hitherto unavailable. In simulations, the shift to LES allows better representation of the turbulent flow in complex geometries, but despite the fact that the grid size is smaller than in RANS, the push towards realistic conditions and the need to include more detailed chemistry that includes very fast species and thin reaction zones emphasize the necessity of a sub-grid turbulent combustion model. The paper discusses examples from current research with experiments and modelling that focus on flame transients (self-excited oscillations, local extinction), sprays, soot emissions, and on practical applications. These demonstrate how current models are being validated by experimental data and the concerted efforts the community is taking to promote the modelling tools to industry. In addition, the various coordinated International Workshops on non-premixed, premixed, and spray flames, and on soot are discussed and some of their target flames are explored. These comprise flames that are relatively simple to describe from a fluid mechanics perspective but contain difficult-to-model combustion problems such as extinction, pollutants and multi-mode reaction zones. Recently, swirl spray flames, which are more representative of industrial devices, have been added to the target flames. Typically, good agreement is found with LES and some combustion models such as the progress variable-mixture fraction flamelet model, the Conditional Moment Closure, and the Transported PDF method, but predicting soot emissions and the condition of complete extinction in complex geometries is still elusive.

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Section: Experimental Diagnosticsmentioning

confidence: 99%

Turbulent Combustion Modelling and Experiments: Recent Trends and Developments

Giusti

Mastorakos

2019

Flow Turbulence Combust

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“…(3) HCO production is directly dependent on the concentration of CH 2 O, that in turn directly depends on the reaction CH 3 + O <=> CH 2 O + H, which shows the largest fractional influence on heat release rate (Paul and Najm, 1998). Nevertheless, Minamoto and Swaminathan (2014), Mulla et al (2016), and Nikolaou and Swaminathan (2014) highlighted the difficulty of accurately measuring HCO concentration due to its low signal to noise ratio, thus suggesting to use the more reliable product of OH and CH 2 O local signals. Indeed, such species are involved as reactants in HCO formation from formaldehyde through the reaction OH + CH 2 O <=> HCO + H 2 O.…”

Section: Introductionmentioning

confidence: 99%

“…In more recent studies, Nikolaou and Swaminathan (2014) and Mulla et al (2016) re-examined the validity of this reaction rate as flame marker for a certain number of combustion conditions. In particular, using Direct Numerical Simulations (DNS) data, they investigated undiluted and diluted methane-air flames, and multicomponent fuel mixtures under both laminar and turbulent conditions.…”

Section: Introductionmentioning

confidence: 99%

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Heat Release Rate Markers for the Adelaide Jet in Hot Coflow Flame

et al. 2020

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In the present work, the correlation between the Heat Releaser Rate (HRR) and species mole fractions and net reaction rates is studied. The PaSR closure model is employed in a RANS framework to implement a detailed kinetic scheme, including the excited species OH*, used as a HRR marker. The effect of oxygen dilution on the combustion regime is investigated, as it can lead to Moderate or Intense Low-Oxygen Dilution (MILD) conditions. Two cases with different levels of oxygen concentration are analyzed. The results suggest the possibility of combining chemical species to construct an appropriate scalar to achieve better correlation with the HRR. It is found that typical markers such as radicals O, OH, OH* correlate fairly well with the HRR but improved correlations can be achieved with appropriate species mole fractions combinations, particularly for the MILD region of the flame.Keywords: heat release rate, heat release rate markers, OH*, laser induced fluorescence, jet in hot coflow, Moderate or Intense Low-Oxygen Dilution Frontiers in Mechanical Engineering | www.frontiersin.org

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“…Vagelopoulos and Frank [23] have demonstrated that the methylidyne radical (CH) follows heat release image reasonably well and can be used as a flame marker in undiluted methane flames at the stoichiometric condition. Various groups have also measured CH2O and OH radicals and found that product of OH and CH2O radicals correlates well with the HRR for turbulent premixed flames under various conditions including premixed flames approaching the blow-off conditions [24][25][26][27]. However, experiments are typically restricted to two-dimensional sections of the flame while the three-dimensional description of the flame generally requires three-dimensional numerical simulations.…”

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confidence: 99%

Heat release rate variations in high hydrogen content premixed syngas flames at elevated pressures: Effect of equivalence ratio

Dinesh

Shalaby

Luo

et al. 2017

International Journal of Hydrogen Energy

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Three-dimensional direct numerical simulations with detailed chemistry were conducted to investigate the effect of equivalence ratio on spatial variations of the heat release rate and flame markers of hydrogen/carbon monoxide syngas expanding spherical premixed flames under turbulent conditions at elevated pressures. The flame structures and the heat release rate were analysed in detail for fuel-lean, stoichiometric and fuel-rich centrally ignited spherical flames. The equivalence ratio changes the balance among thermodiffuive effects, Darrieus-Landau instability and turbulence, leading to different flame dynamics and the heat release rate distribution, despite exhibiting similar cellular and wrinkling flames. The Darrieus-Landau instability is relatively insensitive to the equivalence ratio while the thermo-diffuive process is strongly affected by the equivalence ratio. As the thermo-diffusive effect increases as the equivalence ratio increases, the fuel-lean flame is more unstable than the fuel-rich flame with the stoichiometric flame in between, under the joint effects of the Darrieus-Landau instability and the thermo-diffusive effect. The local heat release rate and curvature display a positive correlation for the lean flame, no correlation for the stoichiometric flame, and negative correlation for the rich flame. Furthermore, the low and high heat release rate values for the fuel-lean flame are found in the negative and positive curvature zones, respectively, while the oppostite trends are found in fuel-rich flame. It is found that heat release rate markers based on species concentrations vary strongly with changing equivalence ratio. The results suggest that the HCO concentration and product of OH and CH2O concentrations show good correlation with the local heat release rate for H2/CO syngas-air stoichiometric flame under turbulent conditions at elevated pressures.3

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Heat release rate estimation in laminar premixed flames using laser-induced fluorescence of CH2O and H-atom

Cited by 51 publications

References 35 publications

Turbulent Combustion Modelling and Experiments: Recent Trends and Developments

Turbulent Combustion Modelling and Experiments: Recent Trends and Developments

Heat Release Rate Markers for the Adelaide Jet in Hot Coflow Flame

Heat release rate variations in high hydrogen content premixed syngas flames at elevated pressures: Effect of equivalence ratio

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