Soot Concentration Research Articles

Pollutant and heat removal of a small fire in a cinema hall by different ventilation systems

This paper investigates the effects of chair burning on the concentration of toxic gases and heat exhaust in a cinema hall. Different ventilation systems, including displacement ventilation (DV), impingement jets ventilation (IJV), stratum ventilation (SV), and hybrid ventilation (combination of displacement and stratum ventilation) were considered in this study. Large Eddy Simulation (LES) of the turbulent flows was performed using Pyrosim software. Concentrations of the toxic gases (CO and CO2) and the heat generated by the fire in the exit doors have been discussed in detail. Concentrations of the generated toxic gases from the fire in all three systems were within the permissible safe ranges. However, among the tested systems, displacement ventilation and impingement jet had better results. Displacement ventilation could decrease the concentrations of soot by 31%, CO by 16%, and CO2 by 11% rather than stratum ventilation. The maximum concentrations of CO and CO2 were 6.35 ppm and 335 ppm, respectively, in the displacement ventilation system. For the stratum ventilation, the concentrations of CO and CO2 were reported 7.5 ppm and 370 ppm, respectively. Using the displacement and the impingement jet ventilation systems, the heat exhaust from door #1 and door #2 are, respectively, 66.6%, and 96% lower than those obtained by the stratum ventilation system.

Utilization of Soot and 210 Po-210 Pb Disequilibria to Constrain Particulate Organic Carbon Fluxes in the Northeastern South China Sea

Black carbon (BC) is believed to be refractory and thus affects the timescale of organic carbon conversion into CO2 and the magnitude of the sink of CO2. However, the fate of BC in the oceans remains poorly understood. Here, 210Po and 210Pb were measured to examine the export of soot in the northeastern South China Sea (SCS). Concentrations of soot decreased from 0.141 ± 0.021 μmol-C L–1 (mean ± SD) in the mixed layer (0–30 m) to 0.087 μmol-C L–1 at the euphotic base (150 m) due to potential photodegradation within the euphotic zone. In the twilight zone, however, the soot showed an increasing pattern along with the total particulate matter and total particulate organic carbon (POC) contents, corresponding to additions from the shelf/slope sediment resuspension through lateral transport. Using the deficits of 210Po, the export flux of soot from the euphotic zone was calculated to be 0.172 ± 0.016 mmol-C m–2 d–1 and increased with depth. Assuming that the soot is entirely refractory below the euphotic zone, the sediment-derived soot fluxes were estimated based on the increase in soot fluxes relative to the base of the euphotic zone, with values varying from 0.149 ± 0.030 to 0.96 ± 0.10 μmol-C L–1. This indicates that sediment resuspension is an important source of soot to the ocean interior in the SCS. Coupling the sediment-derived soot and 210Po-derived POC fluxes gave rise to a Martin Curve-like flux attenuation of local euphotic zone-derived POC in the twilight zone with b value of 0.70 ± 0.01. These results suggest that soot could be useful for constraining in situ POC fluxes and their transport.

Numerical simulation of the effect of LPG blending on the characteristics of a diesel engine

AbstractThe present work aims to investigate numerically the effect of LPG blending on the characteristics of diesel engines subjected to variable compression ratio, injection timing, and engine speed. Three blends of LPG are used, which are 10% LPG + 90% diesel, 20% LPG + 80% diesel, and 30% LPG + 70% diesel. The numerical investigation is carried out using the simulation software Diesel‐RK. Increasing the percentage of LPG in diesel starts combustion early where the lowest delay period is recorded for a blend of 30% LPG + 70% diesel 6.36 deg. The combustion pressure and heat release are decreased due to the difference in the heating values of blended fuels. Although the peak energy release for diesel is 0.05458 (1/deg.) at 375 deg. BTDC, it was 0.0542, 0.05424, and 0.0537 (1/deg.) at 375 deg. BTDC for 10%, 20%, 30% LPG, respectively. Diesel with 30% LPG has a higher spray penetration followed by 20% LPG then 10% LPG and diesel come last. The diesel with 10% LPG gives a 5.35% reduction in NOx, while diesel with 20% and 30% LPG emit less NOx emission by 9.05% and 16.5%, respectively. Increasing the percentage of LPG in diesel yields to reduce soot concentration because LPG has lower carbon to hydrogen ratio. The lowest ability to emit smoke is detected for fuel with 30% LPG where a 7.4% reduction is obtained. It is worth noting that blending LPG with diesel can fight the trade‐off relation between Soot‐NOx as a reduction in both of them is obtained. Based on the results obtained, the blending ratio is 30% LPG. The obtained results are validated with the results of other researchers.

Soot Volume Fraction Measurements by Auto-Compensating Laser-Induced Incandescence in Diffusion Flames Generated by Ethylene Pool Fire

The main characteristics of pool fire flames are flame height, air entrainment, pulsation of the flame, formation and properties of soot particles, mass burning rate, radiation feedback to the pool surface, and the amount of pollutants including soot released to the environment. In this type of buoyancy controlled flames, the soot content produced and their subsequent thermal radiation feedback to the pool surface are key to determine the self-sustainability of the flame, their mass burning rate and the heat release rate. The accurate characterization of these flames is an involved task, specially for modelers due to the difficulty of imposing adequate boundary conditions. For this reason, efforts are being made to design experimental campaigns with well-controlled conditions for their reliable repeatability, reproducibility and replicability. In this work, we characterized the production of soot in a surrogate pool fire. This is emulated by a bench-scale porous burner fueled with pure ethylene burning in still air. The flame stability was characterized with high temporal and spatial resolution by using a CMOS camera and a fast photodiode. The results show that the flame exhibit a time-varying propagation behavior with a periodic separation of the reactive zone. Soot volume fraction distributions were measured at nine locations along the flame centerline from 20 to 100 mm above the burner exit using the auto-compensating laser-induced incandescence (AC-LII) technique. The mean, standard deviation and probability density function of soot volume fraction were determined. Soot volume fraction presents an increasing tendency with the height above the burner, in spite of a local decrease at 90 mm which is approximately the position separating the lower and attached portion of the flame from the higher more intermittent one. The results of this work provide a valuable data set for validating soot production models in pool fire configurations.

Experimental study on the effect of hydrogen addition on methane/ethylene diffusion flame soot formation based on light extinction measurement

In this study, the mixed diffusion flame soot of methane, ethylene and hydrogen were studied, and the two-dimensional light extinction measurement was applied to investigate the distribution characteristics of the ethylene flame soot concentration with different methane and hydrogen ratios. The soot concentration distribution was analyzed, and the effect of hydrogen addition and methane addition on the soot distribution of a laminar ethylene diffusion flame was investigated. The experiments showed that the flame soot of pure ethylene was mainly distributed in both sides of the flame, which increased first and then decreased in the height direction, and the distribution in the radial direction moved toward the center of the flame as the height increased. The low methane addition in pure ethylene flame will produce a synergistic effect to promote soot formation, and its effect disappeared with the increase of methane addition, and the adding of hydrogen in pure ethylene flame will inhibit soot formation, and the inhibiting effect increased with the increase of hydrogen. When the three gases were blended together, the inhibition effect of hydrogen on soot formation was greater than the promotion effect of methane on soot formation at this ratio.

The ability of natural gas to reduce soot content in diesel exhaust gases

In accordance with the priority directions of development of the motor transport complex of the RF, the use of NGV fuel in transport should expand and by 2035 reach 50% of the total number of trucks and buses in large cities. This is due to a number of factors. The paper presents the results of studies confirming the effectiveness of using natural gas to reduce soot emissions with exhaust gases. In particular, the dynamics of the formation and burnout of soot particles by the angle of rotation of the crankshaft at the working operating mode is considered.

Results of calculations of soot formation in a tractor diesel engine running on biofuel

When burning fuel in a diesel internal combustion engine, soot is an undesirable product. To reduce the soot content in the exhaust gases, it is necessary to know the physical and chemical bases of the process of soot formation and soot burnout. Due to the determining role of acetylene in the formation of polycyclic aromatic hydrocarbons in rich mixtures in the low-temperature zone and the key role of acetylene in the surface growth of a particle in the high-temperature zone, it is concluded that the rate of surface growth of a particle is proportional to the concentration of acetylene in the reaction zone, which can be determined by the gas-kinetic method, numerically solving a system of differential equations for the components of the gas mixture under consideration.

Effects of dwell time of split injection on mixture formation and combustion processes of diesel spray

The effects of dwell time on the mixture formation and combustion processes of diesel spray are investigated experimentally. A commercial multihole injector with a 0.123 mm hole diameter is used to inject the fuel. The injection procedure is either a single or split injection with different dwell times, whereas the total amount of injected fuel mass is 5.0 mg per hole. Three dwell times are selected, that is, 0.12, 0.32 and 0.54 ms, with a split ratio of 7:3 based on previous findings. The vapour phase is observed, and the mixture formation pertaining to the equivalence ratio is analysed using the tracer laser absorption scattering (LAS) technique. A high-speed video camera is used to visualise the spray combustion flame luminosity, whereas a two-colour pyrometer system is used to evaluate the soot concentrations and flame temperature. An analysis of the mixture formation based on the spray evaporating condition reveals a more concentrated area of the rich mixture within a 0.32 ms dwell time. In the shortest dwell time of 0.12 ms, the equivalence ratio distribution decreases uniformly from the rich mixture region to the lean mixture region. In the case involving a shorter dwell time, a suitable position for the second injection around the boundaries of the first injection is obtained by smoothly growing the lean mixture and avoiding the large zone of the rich mixture. Therefore, the shortest dwell time is acceptable for mixture formation, considering the overall distribution of the equivalence ratios. Spray combustion analysis results show that the soot formation rate of the single injection and 0.32 ms dwell time case is high and decreases quickly, implying a rapid reduction in the high amount of soot. Consequently, 0.12 ms can be considered the optimal dwell time due to the ignition delay and relatively low soot emission afforded.

Experimental study on correlation between PAHs and soot in laminar co-flow diffusion flames of n-heptane at elevated pressure

As Polycyclic Aromatic Hydrocarbons (PAHs) are the main precursors of soot formation, the investigation of PAHs formation and PAHs transforming to soot is essential for understanding the soot formation and soot reduction in combustion. This study investigated PAHs and soot formation in laminar co-flow diffusion flames fueled by n-heptane at elevated pressures. By using the combination of Laser-induced Incandescence (LII) and Laser-induced Fluorescence (LIF) techniques, the distributions of PAHs and soot concentration in flames were obtained with the energy of 6 and 48 mJ at various detection times. The flame stability at different pressures was analyzed, and the relationship between the integrated signal intensities of Soot-LII and PAHs-LIF in the region near the flame centerline was discussed. The results revealed that, with the increase of pressure, the flame stability becomes worse and both the soot and PAHs concentrations are increased. The integrated intensities of Soot-LII and PAHs-LIF in the region near the centerline of the flame scale with pn. In addition, the integrated signal intensity of Soot-LII has a good linear correlation with that of the PAHs-LIF, and the slopes of correlations are 0.33 and 1.81 at the laser energy of 6 and 48 mJ respectively.

Concentration of Vehicular and Generators Soot in Lafia Metropolis, Nasarawa State, Nigeria

The concentrations of Pb, Cd, Cr, Al and Fe in Heavy Duty Trucks (HDT), Power Generating Plants (PGP), Motor Vehicles (MV) and Small Generator (SG) Soot derived from the College of Agriculture, Bukan Sidi and Mararaba Akunza in Lafia City, Nigeria, were assessed for the level of contamination using Atomic Absorption Spectrophotometer (AAS). The results indicated that the ranges of heavy metal concentrations in soot (mg/kg) were: Pb (0.0911±0.001 to 0.069±0.008) for the HDTs, (0.775±0.008 to 0.002±0.000) for the PGPs, (0.456±0.000 to 0.091±0.000) for the MVs and (0.837±0.000 to 0.027±0.000) for the SGs. The concentrations of Cd and Cr in the HDTs and PGPs were below the detection limits of the AAS. More so, Cd and Cr in MVs were below the detection limits of the AAS except for one of the MVs which gave a highly objectionable Cr concentration of 4.336±0.004 above WHO permissible limits for emissions into air and water. Al concentrations across the soot samples ranges from (0.126±0.002 to 0.093±0.001) for HDT, (0.170±0.001 to 0.097±0.000) for PGPs, (0.150±0.000 to 0.057±0.001) for MVs; and (1.348±0.000 to 0.518±0.000) for SGs. Iron concentrations ranges from (65.885±0.006 to 27.834±0.009) for HDTs, (62.663±0.004 to 11.422±0.019) for PGPs, (52.448±0.003 to 2.418±0.001) for MV, and (129.433±0.008 to 9.129±0.002) for the SGs. The results revealed that the concentration of Pb, Al and Fe in the HDTs, PGPs, MVs and SGs are above the WHO permissible limits for emissions into air and water. Cd, Cr, Al and Fe concentrations were higher in concentrations in SGs. The presence of heavy metals in the sampled soot portends their transfer to the food chain, especially as crop and vegetable cultivation in and around Lafia city.

Physical and chemical characterization of two kinds of coal-derived soot

The chemical composition, oxidation reactivity, nanostructure, and particle size of two coal-derived soot were experimentally investigated. The soot samples were collected from Yinni (YN) and Datong (DT) single coal combustion flames through a nitrogen-quenched sampling tube. The collected soot samples were then tested on an X-ray photoelectron spectroscopy (XPS) and a thermogravimetric analyzer (TGA) to obtain their surface chemistry and oxidation reactivity. XPS analysis showed that extensive C and O, as well as trace other elements, including S, Na, Fe, and Si, etc., appeared on the surface of the two coal-derived soot. The sp2/sp3 content of YN soot was higher than that of DT soot, indicating the better reactivity of YN soot. The results of TGA experiments showed that the oxidation reaction constant of YN soot was indeed larger than DT soot. Interestingly, the two coal-derived soot contained a portion of unburned ash after the TGA oxidation experiments.The nanostructure and particle size distribution function of soot generated in YN and DT single coal combustion flames were also studied by a self-designed thermophoresis sampling system combined with scanning electron microscopy (SEM) and an online dilution probe in conjunction with scanning mobility particle sizer (SMPS). From the SEM images collected from a relatively low height of the single coal flames, a small-sized individual nascent soot and a large-sized and liquid-like drops were observed. With the increase of flame height, the primary particle size of the two kinds of coal-derived soot aggregates decreased due to oxidation, while the primary particle number increased because of agglomeration. The soot aggregates sampled from higher heights of the two single coal flames had a relatively larger particle size but lower concentration.

Experimental and Numerical Study on the Sooting Behaviors of Furanic Biofuels in Laminar Counterflow Diffusion Flames

Furanic biofuels have received increasing research interest over recent years, due to their potential in reducing greenhouse gas emissions and mitigating the production of harmful pollutants. Nevertheless, the heterocyclic structure in furans make them readily to produce soot, which requires an in-depth understanding. In this study, the sooting characteristic of several typical furanic biofuels, i.e., furan, 2-methylfuran (MF), and 2,5-dimethylfuran (DMF), were investigated in laminar counterflow flames. Combined laser-based soot measurements with numerical analysis were performed. Special focus was put on understanding how the fuel structure of furans could affect soot formation. The results show that furan has the lowest soot volume fraction, followed by DMF, while MF has the largest value. Kinetic analyses revealed that the decomposition of MF produces high amounts of C3 species, which are efficient benzene precursors. This may be the reason for the enhanced formation of polycyclic aromatic hydrocarbons (PAHs) and soot in MF flames, as compared to DMF and furan flames. The major objectives of this work are to: (1) understand the sooting behavior of furanic fuels in counterflow flames, (2) elucidate the fuel structure effects of furans on soot formation, and (3) provide database of quantitative soot concentration for model validation and refinements.

Correlating GDI and Diesel Soot with Carbon Black Surrogates: An MTM-SLIM Study

<div class="section abstract"><div class="htmlview paragraph">Legislations aimed at reducing CO<sub>2</sub> emissions are driving significant changes in passenger car engine hardware and lubricants. Gasoline direct injection (GDI) engines generate combustion soot which can drive wear which is characteristically different to that observed in diesel engines. The increasing market share of GDI engines has encouraged the auto OEMs and the oil suppliers to study this challenge in more depth and seek improvements which do not compromise the innate efficiency benefits of the GDI platform. This study compares soot abrasiveness by measuring the abrasive removal of Zinc dialkyldithiophosphate (ZDDP) antiwear films and resultant wear by GDI sooted oils and traditional Diesel sooted oils in the MTM-SLIM equipment. A three-way correlation has been developed between a carbon black soot surrogate, GDI sooted oils and Diesel sooted oils. Diesel sooted oils were found to be more abrasive and resulted in more severe wear than gasoline sooted oils at the same level of % soot loading. The impact of oil viscosity grade on soot induced wear has been observed. A thinner oil with lower soot concentration led to harsher wear conditions as compared to a thicker oil with higher soot loading. Both, thinner oils and increased soot loading led to increased wear levels, therefore both parameters need to be considered when wear data is being interpreted.</div></div>

Influence of ethanol blending ratios on in-cylinder soot processes and particulate matter emissions in an optical direct injection spark ignition engine

Soot volume fraction distribution of ethanol blended fuels (ethanol volume fraction 0%, 20%, 40% and 60%, named as E0, E20, E40 and E60) were measured in an optical direct injection spark ignition (DISI) engine by combined laser induced incandescence (LII) and two-color (2C) method. Exhaust particulate matter (PM) emissions were measured by a Combustion DMS500 Fast Particulate Analyzer. For DISI engines, pool fire and the resulting diffusion flame are the main sources of soot in the cylinder. Choosing a suitable measurement plane and detection time, laser induced incandescent can be used to quantitatively measure the soot concentration produced by the pool fire. This research explores the effect of ethanol blending on engine particulate matter by comprehensively analyzing the soot process in the cylinder and exhaust particulate emissions. According to the two-dimensional quantitative soot volume fraction results, the maximum average soot volume fraction of the same fuel on the 10 mm plane is greater than the 5 mm plane; on the same plane, E20 shows the highest soot concentration compared to the other fuel blends which could be the physical properties of the ethanol become apparent. For exhaust particle emissions, ethanol can significantly reduce the total particle number and accumulation mode particle number. E0, E40 and E60 show fairly similar behavior between the exhaust particle emissions and the soot-LII imaging measurements. For E20, however, this is in poor agreement when comparing the soot-LII imaging results to the results of exhaust particle emission measurements.

Influence of potassium chloride on PAH concentration during soot formation studied using laser-induced fluorescence

Previous studies have shown that addition of potassium chloride (KCl) reduces soot concentration and primary particle size. To improve the understanding of this phenomenon, this work focuses on investigating the influence of KCl addition on formation of polycyclic aromatic hydrocarbons (PAHs), assumed to be precursors of soot. The method used is laser-induced fluorescence (LIF), for which different size classes of PAHs can be probed using selected combinations of excitation and detection wavelengths. KCl solutions of different concentrations were aspirated into premixed ethylene-air flames, and spectral and 2D imaging PAH-LIF measurements were performed using laser excitation at 266 nm and 532 nm. PAH-LIF spectra using 266 nm excitation showed a peak in the UV region at around 350 nm and a peak at around 550 nm in visible region, where the latter peak intensity increased strongly with flame height. The normalised PAH-LIF spectra obtained using 532 nm excitation showed no spectral change with flame height. The main results from this study showed that KCl addition, firstly, had negligible influence on the formation of smaller PAHs (measured using excitation at 266 nm and detection at ∼ 320 nm), and secondly, decreased the formation of larger PAHs at increasing flame heights (measured using excitation at 532 nm and detection in the visible region).

Simulation of soot formation in a tractor diesel engine running on rapeseed oil methyl ether and methanol

The mass content of soot (C) in the cylinder of a tractor diesel engine (TDE) is directly affected by the temperature conditions, the excess air coefficient, and the chemical composition of the fuel. Methanol (M) does not form C particles during combustion. As the C chain in the fuel molecule increases, the propensity to C formation during combustion increases. However, in the presence of oxygen atoms in the initial fuel molecule, it significantly slows down the rate of nucleation of primary particles. During the evolution of the particle in the cylinder of a TDE when working on rapeseed oil methyl ether and methanol (ROMEM), a number of characteristic stages are identified.

Effect of Varying Aerosol Concentrations and Relative Humidity on Visibility and Particle Size Distribution in Urban Atmosphere

Atmospheric aerosol concentrations have been found to change constantly due to the influence of source, winds and human activities over short time periods. This has proved to be a constraint to the study of varied aerosol concentrations in urban atmosphere alongside changing relative humidity and how it affects visibility and aerosol particle size distribution. In this research simulation was carried out using Optical Properties of Aerosols and Clouds (OPAC 4.0) average concentration setup for relative humidity (RH) 0-99% at visible wavelength 0.4-0.8 μm to vary the concentrations of three aerosol components: WASO (Water-soluble), INSO (Insoluble) and SOOT. The Angstrom exponents (α), the curvatures (α2) and atmospheric turbidities (β) were obtained from the regression analysis of Kaufman’s first and second order polynomial equations for visibility. The research determined the mean exponent of the aerosol size growth curve (µ) from the effective hygroscopic growth (geff) and the humidification factors (γ) from visibility enhancement f (RH, λ). The mean exponent of aerosol size distributions (υ) was determined from µ and γ. The results showed that with varied WASO, INSO and SOOT concentrations respectively at different RH, aerosol particle size distributions showed bimodal characteristics with dominance of fine mode particles. Hazy atmospheric conditions prevailed with increasing turbidity.

Influence of potassium on benzene and soot formation in fuel-rich oxidation of methane in a laminar flow reactor

The influence of potassium chloride (KCl) and potassium hydroxide (KOH) on the formation of benzene and soot in fuel-rich oxidation of methane was investigated experimentally using a flow reactor at atmospheric pressure and temperatures ranging from 1273 to 1673 K. The methane inlet concentration was kept constant at 2 vol.% (nitrogen balance), while the C/O ratio was 2 or 5. The potassium salt was fed into the main gas flow at a comparatively high concentration of around 1000 ppm. The onset of formation of acetylene and benzene was around 1373 K. The addition of both potassium salts was found to promote formation of acetylene and benzene at temperatures below 1523 K. This effect was most pronounced at a high C/O ratio of 5 and in the presence of KOH, but diminished at temperatures above 1523 K. A detailed chemical kinetic model was used to interpret the experimental results and was found to be able to partially reproduce the promoting effect of KOH. According to the model, the addition of KOH facilitates the buildup of OH radicals through the rate controlling reaction KOH + M ⇌ K + OH + M. The promotion of the radical pool favors the formation of active intermediates including methyl and vinyl radicals, both of which play an important role in the major benzene formation pathways under the conditions investigated. Particle analysis using SMPS showed a net increase in the volume concentration of soot and a shift of the particle size distribution towards larger diameters in the presence of KOH, but no quantitative difference was observed for the mass of carbonaceous materials collected on filters.

Prediction of oil dilution formation rate due to post injections in diesel engines by using Gaussian process

Post-injection strategies are commonly used in diesel engines for various purposes, such as cleaning diesel particulate filters from soot, heat-up and heat maintenance strategies. Usage of post injections in diesel engines with upcoming legislation is expected to be increased because of increasing regeneration frequencies, de-sulfation of catalysts and challenges in cold emission. Post injections with retarded timing and high quantity under certain charge conditions can cause oil dilution by creating liquid fuel impingement on lubricated cylinder walls and the fuel absorption into the oil film. Fuel contamination to engine oil can cause deterioration in oil properties. Engine components can only bear a certain level of degradation in oil properties. Thus, exceeding a certain level of oil dilution should be avoided not to harm engine durability. The engine oil must be replaced within a specific interval due to various mechanisms affecting engine oil lubrication performance such as ageing, soot content etc. Depending on the fuel rate going into the engine oil, oil dilution due to post injections can limit engine oil change intervals. Engine oil change interval is essential for the cost of ownership and environment. Parameters such as charge conditions at post-injection timing and post-injection configuration are effective over the formation rate of oil dilution due to post injections. Therefore, the formation rate of oil dilution due to post injections must be minimized and modelled not to exceed a specific limit in different cycles. With this study, a series of engine testing is conducted to investigate the correlation between empirical spray parameters and fuel in oil formation rate due to post injections. During the studies, various charge conditions and post-injection configurations were tested. In addition to fuel addition to oil, fuel evaporation from oil was also investigated. A correlation between penetration depth and the formation rate of oil dilution was observed. However, a correlation between Sauter means diameter and formation rate of oil dilution was only kept when penetration depth was filtered within a specific range in test results. Evaporation of fuel in oil has shown an asymptotic behaviour based on test duration and initial heavy fraction ratio under constant oil temperature conditions. A statistical modelling approach is applied to predict the formation rate of oil dilution as a function of normalized spray penetration depth, Sauter means diameter and engine speed. Moreover, such a model was validated over various transient cycles.

A calibration-free two-dimensional spectral soot emission platform for temperature and soot measurements

A simple and cost-effective temperature and soot volume fraction measurement technique that does not rely on spectral or absolute irradiance calibration is developed. The technique is based on a three-sensor CMOS camera, where the broadband sensitivity of RGB sensors were narrowed down to representative wavelengths using a tri-bandpass filter. A telecentric imaging lens was used to improve the accuracy of the tomographic deconvolution of the axisymmetrical ethylene laminar diffusion flames stabilized on a co-flow burner. Temperature and soot concentration measurements have been compared with results previously reported from the same burner. Good agreement for temperature measurements and excellent agreement for soot concentration measurements have been shown. Additionally, to demonstrate the dynamic range of the system, two-dimensional temperature and soot volume fraction fields were measured for four cases of dilution corresponding to various soot loadings. As the dilution rate was increased, the peak soot volume fraction was drastically reduced and temperatures were increased in accordance with the reduced dissipative heat losses from broadband soot radiation.