Location Of Reaction Zone Research Articles

Frozen autocatalytic fronts in a radial flow

Autocatalytic reaction-diffusion fronts are localized reaction zones propagating at a constant speed with a constant width. We show both theoretically and experimentally that, if the reactant Y of the autocatalytic reaction is injected radially at a constant flow rate in a sea of the autocatalytic species X, a stationary front can be maintained at a fixed position that scales linearly with the flow rate. When this reaction front is about to reach a stationary state, a second outward traveling front emerges to adapt the outer concentration of the autocatalytic species to the stoichiometry ratio between X and Y. Simple analytical solutions to the reaction-diffusion-advection equations governing the dynamics are computed for both fronts. The analytical predictions for the stationary front position and moving front dynamics as a function of injection flow rate, reactant concentration, and gap of the quasi-two-dimensional reactor agree well with experimental results obtained with the autocatalytic chlorite-tetrathionate reaction. Published by the American Physical Society 2024

On the Analysis of Scale Effects of Flame Stabilization in Scramjet Combustors

Scale effects of flame stabilization in scramjet combustors at Mach 2.52 are investigated through experiments and numerical simulations based on two geometrically similar combustors. As the equivalence ratio increases, the combustion mode will change from Scram to Dual to Ram. However, the larger combustor has a delayed mode transition. The scale effects of flame stabilization are also reflected in the changes of heat release, precombustion shock train length, jet penetration depth, and reaction zone location. The combustion flowfields of different-scale combustors exhibit numerous differences under different combustion modes. However, after shortening the isolator of the proportionally scaled small-scale combustor, the combustion flowfield is closer to that of the large-scale combustor. Further analysis reveals the reason for the inconsistent scale effects of flame stabilization under different combustion modes. The probable reason is that the boundary layer, which does not change proportionally with the combustor scale, has different effects on the combustion under the three modes. Compared with the Scram and Ram modes, the scale effect in the Dual mode is the most significant because the strong interaction between heat release and the boundary layer amplifies the slight difference in the relative thickness of the boundary layer.

Local Thermochemical Mechanisms in Direct Solar Graphite Synthesis from Methane.

Methane pyrolysis is known to produce hydrogen and solid carbon in a variety of thermal processes. However, the generated carbon product typically belongs to a low-value amorphous type. Here, we elucidate the thermochemical mechanisms of a reaction that produces high-quality graphite via direct solar methane pyrolysis on a porous substrate. By comparing graphite deposition rates and local reaction zone temperatures of exposed and shadowed regions from the same experiment, we clarify the effects of thermolysis and photolysis in this emission-free process that both decarbonizes a fuel and produces a critical material for the sustainable energy transition.

Gas‐free initiation for free‐radical frontal polymerization through charge transfer complexes

AbstractFrontal polymerization is a process in which a localized reaction zone propagates through the coupling of thermal transport and the Arrhenius kinetics of exothermic polymerization. Most initiators that have been used produce volatile by‐products, which create bubbles and voids. Tetraalkyl ammonium persulfates have been used but these require synthesis and do not have long shelf lives. A charge transfer complex (CTC) composed of an iodonium salt, and a phosphine compound has been identified as a gas‐free initiator for free‐radical thermal frontal polymerization. This CTC has 4‐(dimethylamino)phenyldiphenly phophine (DMAPDP) as the donor and p‐(octyloxyphenyl)phenyliodonium hexafluoroantimonate as the acceptor (IOC‐8). The CTC was tested with several acrylates, and all were found to support bubble‐free fronts. We determined the CTC mole ratio for some monomers at which the front velocity reaches a plateau.

Opposite effects of flame-generated potential and solenoidal velocity fluctuations on flame surface area in moderately intense turbulence

To explore the influence of dilatational and rotational motions on iso-scalar surface area within a premixed turbulent flame, three-dimensional compressible direct numerical simulation data obtained by Dave et al. (2018) from a lean, complex-chemistry, hydrogen-air flame propagating in intense small-scale turbulence (a ratio of laminar flame thickness to Kolmogorov length scale is about 20) in a box are analyzed using Helmholtz–Hodge decomposition of velocity field into solenoidal and potential components. The obtained results indicate that the flame surface area is created by potential velocity fluctuations generated due to combustion-induced thermal expansion, whereas the rotational motion acts to smooth wrinkles of iso-scalar surfaces within local preheat and reaction zones and, consequently, to reduce the flame surface area. The latter finding challenges the classical concept of flame-generated turbulence and is attributed to flame-generated solenoidal velocity fluctuations. Specifically, the incoming tangential (to the flame) vorticity is suppressed by baroclinic torque, which also generates vorticity in another tangential direction, with the latter (flame-generated) solenoidal velocity fluctuations working to smooth the flame surface. Thus, even under conditions of moderately intense turbulence, flame surface area can primarily be created by potential velocity perturbations caused by combustion-induced thermal expansion.

A co-kurtosis PCA based dimensionality reduction with nonlinear reconstruction using neural networks

For turbulent reacting flow systems, identification of low-dimensional representations of the thermo-chemical state space is vitally important, primarily to significantly reduce the computational cost of device-scale simulations. Principal component analysis (PCA), and its variants, are a widely employed class of methods. Recently, an alternative technique that focuses on higher-order statistical interactions, co-kurtosis PCA (CoK-PCA), has been shown to effectively provide a low-dimensional representation by capturing the stiff chemical dynamics associated with spatiotemporally localized reaction zones. While its effectiveness has only been demonstrated based on a priori analyses with linear reconstruction, in this work, we employ nonlinear techniques to reconstruct the full thermo-chemical state and evaluate the efficacy of CoK-PCA compared to PCA. Specifically, we combine a CoK-PCA-/PCA-based dimensionality reduction (encoding) with an artificial neural network (ANN) based reconstruction (decoding) and examine, a priori, the reconstruction errors of the thermo-chemical state. In addition, we evaluate the errors in species production rates and heat release rates, which are nonlinear functions of the reconstructed state, as a measure of the overall accuracy of the dimensionality reduction technique. We employ four datasets to assess CoK-PCA/PCA coupled with ANN-based reconstruction: zero-dimensional (homogeneous) reactor for autoignition of an ethylene/air mixture that has conventional single-stage ignition kinetics, a dimethyl ether (DME)/air mixture which has two-stage (low and high temperature) ignition kinetics, a one-dimensional freely propagating premixed ethylene/air laminar flame, and a two-dimensional dataset representing turbulent autoignition of ethanol in a homogeneous charge compression ignition (HCCI) engine. Results from the analyses demonstrate the robustness of the CoK-PCA based low-dimensional manifold with ANN reconstruction in accurately capturing the data, specifically from the reaction zones.

Characteristics of ammonia-hydrogen nonpremixed bluff-body-stabilized flames

The combustion of ammonia (NH3) has received much attention over the last few years due to challenges associated with its low reactivity and the emission of nitric oxides. One way to improve the reactivity of NH3 is to blend it with (H2/N2) mixture as the product of its dissociation, before introducing it into energy systems. In this study, experimental measurements were carried out on nonpremixed bluff-body stabilized flames to better understand the flame and emission characteristics of NH3/H2/N2 flames. Four fuel mixtures at different NH3 and (H2/N2) ratios were investigated to represent different levels of ammonia cracking. Photography, planar laser-induced fluorescence of OH, thermocouples, and gas analysis techniques were used to understand flame features, reaction zone characteristics, NO, and NH3 concentration within the flame and at the exhaust. It was observed that a decrease in NH3 ratio in the mixtures resulted in longer and more stable flame with reduced thermal radiation as compared to NH3-rich fuel blends. For the highest NH3 blend studied, the flames exhibit extinction and re-ignition in the neck zone, as evidenced by OH-planar images and temperature profiles. As the H2/N2 ratio in the fuel mixture is increased, while keeping the Re constant, the momentum flux ratio (jet/co-flow) also increased resulting in a fuel-lean recirculation zone (RZ), and a shift in the maximum temperature and OH region from the outer shear layer to the inner layer next to the central jet. At levels of NH3 in the fuel mixture above 50% by volume, unburned ammonia slips through the flame and into the exhaust, and the subsequent reburn mechanism resulted in reduced NO emission. CFD simulations using Reynolds-averaged Navier-Stokes (RANS) and the flamelet–progress-variable submodel were conducted and compared with the experimental results. The CFD results helped to qualitatively describe and further explain what was observed in the experiment including the flame appearance, mixing field, and the reaction zone location in the tested flames.

A DNS study of pulverized coal combustion in a hot turbulent environment: Effects of particle size, mass loading and preferential concentration

In the present study, pulverized coal combustion in a hot turbulent environment is investigated using direct numerical simulation (DNS). The coal particles are tracked in the Lagrangian framework while the flow is solved in an Eulerian way. A model involving two competing reactions is used for describing the process of coal devolatilization. The volatile matter is treated as a postulated substance (CaHbOc) and a two-step global reaction mechanism for volatile combustion is adopted. The char combustion is modeled using a one-step global reaction model. The effects of various factors, such as particle size, mass loading and preferential concentration, on the combustion process of coal particles were explored. It was found that, the location of reaction zones appears more upstream and the volatile matter concentration is higher for the cases with smaller particles. The combustion modes were examined. It was shown that the contribution of premixed combustion decreases with increasing particle size while non-premixed combustion prevails in all cases. The increase of particle mass loading results in an increase of volatile matter mass fraction, which leads to higher heat release rate and combustion temperature. Through Voronoï analysis, the preferential concentration of particles was examined. It was found that the preferential concentration behavior of particles is more prominent when the particle Stokes number (St) is close to unity. The volatile matter concentration is higher when particles are preferentially concentrated, facilitating coal particles to ignite.

Initial response and combustion behavior of microscale Al/PTFE energetic material by nanosecond laser ignition

Al/PTFE reactive material has potential applications in defense and military due to its good thermodynamic properties and strong stability. To clarify its microscopic reaction process, the initial response and combustion behavior from microsecond up to several milliseconds are fully exhibited via laser-induced plasma spectroscopy and high-speed schlieren photographs while varying the ignition energy. Totally different plasma chemistry and combustion behavior of microscale Al/PTFE (mole ratio of 4:3) from those of pure Al are recorded. The fading of AlO and CN emissions and enhancement of C2 emission from the composite plasma with increase of laser energy prove that Al-F exothermic combination dominate the initial response since the decomposed gases of PTFE keep most Al away from air to be oxidized. The acceleration of laser-induced shockwave by a local high temperature reaction zone at the expanding plume front along the direction of laser beam is illustrated. As the plasma quenched and transformed to combustion at later stage, an ellipsoidal flame generally occurs above the surface for PTFE composite due to the upward move of Al vapor with PTFE decomposition gas while the combustion from pure Al exhibits a horizontal expansion along the surface. Self-sustained combustion of micro-Al/PTFE lasts around 1 ms is observed at extreme high energy of 1100 mJ. Inside flame plume, the transmission of decomposition matter and energy between different flame parts are clarified. Finally, a qualitative reaction model is built to successfully describe the response and combustion behavior after nanosecond laser ignition in detail. This study provides the support for the application of these insensitive reactive materials in laser ignition.

Numerical analysis of multi-regime combustion using flamelet generated manifolds - a highly-resolved Large-Eddy Simulation of the Darmstadt multi-regime burner

Multi-regime effects occur due to the interaction of combustion phenomena such as partial premixing of reactants or product-recirculation and lead to the invalidity of idealization of local reaction zones by purely premixed or purely non-premixed flame structures. The recently proposed multi-regime burner (MRB) at the Hochschule Darmstadt and the TU Darmstadt is investigated using highly-resolved Large-Eddy Simulation (LES) regarding the present combustion modes – with focus on MILD combustion – and overall flame characteristics. Thermochemical experimental data and highly resolved LES are compared for two selected operating conditions MRB18b and MRB26b. The experimental investigation focuses on the overall flame structure by examining radial profiles of temperature and mixture fraction, as well as scatter plots of temperature and CH4 versus mixture fraction. The objective of this analysis is to provide insights into the reaction zone structure which are difficult to extract by experimental means, by using highly-resolved Large-Eddy Simulations under flow conditions representative of MRB18b and MRB26b. The generated database was used to allow for a separate analysis of the inner and outer flame branches. SO2 measurements were analyzed together with the simulated temperature fields to further assess the flame stabilization mechanism in this configuration. The importance of different flame zones and burning modes was analyzed using the flame index and temperature locus diagrams. The effects of the flame zones are found to evolve with the downstream distance and show distinct differences between the two operating conditions. The applied diagnostics reveal the spatial and thermodynamical state of the different regimes.

Redox cationic frontal polymerization: a new strategy towards fast and efficient curing of defect-free fiber reinforced polymer composites.

Frontal polymerization of epoxy-based thermosets is a promising curing technique for the production of carbon fiber reinforced composites (CFRCs). It exploits the exothermicity of polymerization reactions to convert liquid monomers to a solid 3D network. A self-sustaining curing reaction is triggered by heat or UV-radiation, resulting in a localized thermal reaction zone that propagates through the resin formulation. To date, frontal polymerization is limited to CFRCs with a low fiber volume percent as heat losses compromise on the propagation of the heat front, which is crucial for this autocatalytic curing mechanism. In addition, the choice of suitable epoxy monomers and thermal radical initiators is limited, as highly reactive cycloaliphatic epoxies as well as peroxides decarboxylate during radical induced cationic frontal polymerization. The resulting networks suffer from high defect rates and inferior mechanical properties. Herein, we overcome these shortcomings by introducing redox cationic frontal polymerization (RCFP) as a new frontal curing concept. In the first part of this study, the influence of stannous octoate (reducing agent) was studied on a frontally cured bisphenol A diglycidyl ether resin and mechanical and thermal properties were compared to a conventional anhydride cured counterpart. In a subsequent step, a quasi-isotropic CFRC with a fiber volume of >50 vol%, was successfully cured via RCFP. The composite exhibited a glass transition temperature > 100 °C and a low number of defects. Finally, it was demonstrated that the redox agent effectively prevents decarboxylation during frontal polymerization of a cycloaliphatic epoxy, demonstrating the versatility of RCFP in future applications.

Understanding surface charge effects in electrocatalysis. Part 2: Hydrogen peroxide reactions at platinum

Electrocatalytic activity is influenced by the surface charge on the solid catalyst. Conventionally, our attention has been focused on how the surface charge shapes the electric potential and concentration of ionic reactant(s) in the local reaction zone. Taking H2O2 redox reactions at Pt(111) as a model system, we reveal a peculiar surface charge effect using ab initio molecular dynamics simulations of electrified Pt(111)-water interfaces. In this scenario, the negative surface charge on Pt(111) repels the O–O bond of the reactant (H2O2) farther away from the electrode surface. This leads to a higher activation barrier for breaking the O–O bond. Incorporating this microscopic mechanism into a microkinetic-double-layer model, we are able to semi-quantitatively interpret the pH-dependent activity of H2O2 redox reactions at Pt(111), especially the anomalously suppressed activity of H2O2 reduction with decreasing electrode potential. The relevance of the present surface charge effect is also examined in wider scenarios with different electrolyte cations, solution pHs, crystal facets of the catalyst, and model parameters. In contrast with previous mechanisms focusing on how surface charge influences the local reaction condition at a fixed reaction plane, the present work gives an example in which the location of the reaction plane is adjusted by the surface charge.

Flame folding and conditioned concentration profiles in moderately intense turbulence

While the flamelet paradigm offers the opportunity to simplify computations of mean species concentrations in turbulent flames, a widely accepted criterion of the validity of this paradigm has not yet been elaborated. In this regard, different physical mechanisms are discussed, and flame folding is one of them. The present work aims at exploring the eventual influence of flame folding on the local flame structure in a turbulent flow. For this purpose, a new diagnostic technique was applied to processing complex-chemistry direct numerical simulation data obtained earlier from a lean hydrogen-air turbulent flame [Dave and Chaudhuri, J. Fluid Mech. 884, A46 (2020)]. The technique consists of counting crossing numbers Nf for a cold boundary of the local reaction zone and a ray normal to the mean flame brush, followed by analyzing statistics sampled from rays characterized by Nf≥3. More specifically, profiles of species mole fractions, temperature, heat release rate, and species production rates, conditioned to combustion progress variable and either Nf or axial distance Δx between two neighboring reaction zones, are sampled and compared with the counterpart profiles obtained from the laminar flame. Results show that these doubly conditioned profiles are close to each other for various crossing numbers or for various axial distances even if the distance is as small as half laminar flame thickness. The lack of a substantial effect of the crossing number or the axial distance on the doubly conditioned profiles implies that small-scale flame folding does not limit the validity of the flamelet paradigm.

The effect of syngas addition on flameless natural gas combustion in a regenerative furnace

The present work numerically and experimentally studies the mixture of 30% syngas and 70% natural gas (SG-NG), by volume, and compares performance to pure natural gas (NG). The experimental measurements were carried out in a semi-industrial regenerative furnace originally designed for pure natural gas. A 25 kW thermal input and a 1.2 excess air ratio were maintained throughout. Temperatures and species were measured inside the combustion chamber. The effect of the syngas on the reaction zone location was determined by imaging spontaneous chemiluminescence. The effect of preheating was also studied for the SG-NG mixture. CFD modeling was used to analyze the effects on recirculation patterns. SG-NG exhibited an average temperature decrease of 6% compared to NG, due to the greater recirculation and increased CO2 in the flue gases. The species uniformity remained consistent, while the thermal uniformity factor (RTU) decreased by 10.5%, indicating greater uniformity. NOx emissions decreased by almost 50% for the SG-NG mixture. The addition of syngas improved the reactivity and displaced the reaction zone upstream. Without preheating, the recirculation and the reactant dilution decrease, generating a disturbance in the thermal uniformity (RTU increase by 65%) and the reaction zone was displaced downstream.

Ridge-based reaction zone characterisation in non-premixed flames

We apply ridge analysis for reaction zone characterisation in non-premixed combustion. Generalizing the topographical mountain-ridge archetype, ridges are low-dimensional regions where a scalar field has elevated values (local maxima) along intrinsically given directions. Ridge analysis of a chemical source term field can identify the reaction zone location, and also describe the spatial extent and shape of the zone. The concept is explored for non-premixed combustion by identifying ridges of a chemical source term field in three-dimensional Direct Numerical Simulation (DNS) data of a non-premixed, strongly diluted turbulent hydrogen/air flame. Properties of the ridge-based flame front are presented and discussed. The method reveals different reaction zone geometry types in the DNS data, including the conventional flame sheet, but also other, less common reaction zone structures like filaments or patches. A significant part of the combustion occurs in filament-shaped reaction zones, rather than in “classical” flame sheets. Comparison of the reaction zone derived from ridge analysis and the reaction zone derived from the stoichiometric iso-surface of mixture fraction shows profound differences in location, and also in reaction-front conditioned statistics of scalars. These findings, along with the intrinsic nature of the ridge concept — requiring no definitions of thresholds, iso-values or similar — confirm the usefulness of the method for the analysis of reacting flows.

Charge transfer complexes as dual thermal/photo initiators for free‐radical frontal polymerization

AbstractFrontal polymerization is a process in which a localized reaction zone propagates from the coupling of thermal transport and the Arrhenius rate dependence of an exothermic polymerization; monomer is converted into polymer as the front passes through an unstirred medium. Herein we report the first study of charge transfer complexes (CTCs) as photo/thermal initiators for free‐radical frontal polymerization. Front velocity was studied as a function of mole ratio between an aromatic amine, such as dimethyl‐p‐toluidine or dimethylaniline, and an iodonium salt. It was found that the front velocity reached a maximum at a certain mole ratio of amine to iodonium salt. The velocity remained constant upon increasing the ratio of amine to iodonium salt past this critical ratio. Fronts were also studied using N‐phenyl glycine as an electron donor, but its utility was limited by low solubility. Lastly, the steric and electronic effects of the iodonium salt and counter anion were explored. It was found that CTCs using iodonium salts with less nucleophilic anions gave higher front velocities. In terms of intrinsic reactivity, the CTC composed of N,N‐dimethyl‐p‐toluidine and bis[4‐(tert‐butyl)phenyl]iodonium tetra(nonafluoro‐tert‐butoxy)aluminate gave the highest front velocity per molal of iodonium salt.

Optical Equivalence Ratio Measurement of a Dual Fuel Burner for Natural Gas and Kerosene

A measurement technique for determination of the global and local equivalence ratios from the flame chemiluminescence for a swirl-stabilized lean premixed combustion of natural gas and kerosene is presented. First, we conducted spectrally resolved chemiluminescence studies using an imaging spectrometer to correlate the ratio of individual chemiluminescence signals to the equivalence ratio. Flame spectra were recorded for a multitude of different lean operating conditions for natural gas and kerosene combustion. The spectra show that, without background correction, the CH*/CO2* ratios for both natural gas and kerosene combustion exhibited a monotonic relationship to the equivalence ratio in the investigated range. Subsequently, bandpass-filtered images of CH* and CO2* chemiluminescence were acquired simultaneously on one camera chip using an image doubler to investigate the local relationship of the CH*/CO2* ratio with the equivalence ratio. The ratio images corroborate the monotonic relationship of the CH*/CO2* ratio to the equivalence ratio. Furthermore, the ratio was found to be influenced by the local reaction zone temperature. The presented technique allows high temporal resolution determination of the local equivalence ratio in lean premixed natural gas and kerosene flames and can thus be applied to quantify equivalence ratio oscillations during unstable combustion.

Investigation of mixing processes of effusion cooling air and main flow in a single sector model gas turbine combustor at elevated pressure

Mixing processes between main flow and effusion cooling air are investigated in an effusion cooled, swirl-stabilized pressurized single sector gas turbine combustor using advanced laser diagnostics. Quantitative planar laser-induced fluorescence of the hydroxyl radical (OH-PLIF) and planar laser-induced fluorescence of nitric oxide, seeded to the effusion cooling air, (NO-PLIF) are employed in the primary zone and close to the effusion cooled liner. This data is used to identify mixing events at three stages of premixed combustion, i.e. mixing before reaction, mixing during reaction and mixing after reaction. A parametric study of swirl and cooling air mass flow is conducted to investigate the mutual interaction between flame and cooling air. Within the primary zone, a significant radial asymmetry of OH concentration is observed. This asymmetry is partly explained by the presence of effusion cooling air within the unburned fresh gas, leading to lowered OH concentration within local reaction zones and their post-flame equilibrium concentration. Near the effusion cooled liner, adiabatic mixing after reaction is the dominant process across all investigated operating conditions. Notable mixing before reaction is only observed for the first effusion hole on the center line at low swirl conditions.

Effect of combustion zone material on the thermal performance of a biogas-fuelled porous media burner: Experimental studies

The performance of a porous media burner (PMB) is immensely dependent on the selection of porous material. Present experimental work investigates the impact of burner’s material on the thermal performance of a crude biogas-fuelled, in house developed PMB. This includes the study of burner stable operating limits, location of reaction zone, estimation of radiation efficiency and exhaust gas emission analysis. The PMB consists of two sections of porous material, one is the combustion zone and the other is the preheat zone. In the present research, the impact of combustion zone material on performance of the PMB is tested, while keeping the material of preheat zone unchanged. Silicon carbide (SiC) and zirconia (ZrO2) foams, both having porosity of 10 ppi, have been chosen as combustion zone. Experimental investigation shows that for the whole input load range of 5–10 kW, the SiC foam offered lean working condition, while in case of ZrO2, similar condition was limited to 5–8 kW. Within these stable operating limits, the axial temperature mapping of the burner highlights the location of reaction zone. Combustion in SiC foam is found to offer higher radiation efficiency of maximum 23.7%, as compared to that of ZrO2, where it is only 8%. Exhaust gas analysis shows that CO and NOx concentrations of both burners were low and the maximum values were limited to 156 ppm and 20 ppm, respectively. Overall performance assessment confirms that SiC is a better choice over ZrO2 for lean combustion of crude biogas in the developed PMB.

Statistical relationship between soot volume fraction, temperature, primary particle diameter and OH radicals along transects normal to the local reaction zone in a turbulent flame

We present a new method to extract experimental data from simultaneous planar images in turbulent sooting flames, to derive transects of key species based on local coordinates that are aligned normal to the instantaneous, fluctuating reaction zone. Such statistics represent a milestone in the assessment of turbulent sooting flames, because they are one-dimensional and based on local coordinates conditioned on the distribution of soot sheets, in contrast to previous statistics, which are typically Eulerian and single point in nature. The local coordinate system was determined from instantaneous images of soot volume fraction (fv) based on a varying threshold and the local reaction zone was identified by further referring OH images. Quantitative experimental data of fv, temperature (T) and primary particle diameter (Dp), together with qualitative OH intensities, were extracted along the direction normal to the local reaction zone from simultaneous images of the four parameters. These results were measured in a pre-vaporized toluene diffusion flame (Reynolds number = 10,000) using advanced laser-based techniques. Statistical data were combined together and used to generate the profiles for these four parameters with high accuracy and level of resolution that is not possible using previous statistics methods based on Eulerian coordinates. These new kind results showed that the spatial relationship between fv, T and OH remains broadly similar anywhere in the flame, while the profiles of Dp significantly shift away from those of the other three parameters with the increase in the height of the flame. The mean values of fv, Dp and T also show a clear relationship as a function of the height, even though the trends of mean fv and Dp along the height are different from that of T, also suggesting a strong relationship exists between soot and temperature in the local reaction zone.