Andrey G. Shmakov

Russian Academy of Sciences | RAS · Voevodsky Institute of Chemical Kinetics and Combustion

Understanding and controlling the combustion of clean and efficient fuel blends, like methane + hydrogen, is essential for optimizing energy production processes and minimizing environmental impacts. To extend the available experimental database on CH4 + H2 flame speciation, this paper reports novel measurement data on the chemical structure of lam...

The presented work examines the combustion of a hydrogen microjet flowing from a curved channel with a round micronozzle. Jet flows that are generated using rectilinear and curved channels differ in that in the second case, Dean vortices make a noticeable contribution to the formation of the jet and its combustion. The interaction of the latter wit...

The flammability of various materials used in industry is an important issue in the modern world. This work is devoted to the study of the effect of flame retardants, graphene and DDM-DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-4,4′-diamino-diphenyl methane), on the flammability of glass-fiber-reinforced epoxy resin (GFRER). Samples we...

The results of an investigation of the interaction between two colliding axisymmetric laminar microjets of propane-butane mixture with and without diffusion combustion are presented. The gas mixture components flow out through round tubes at the same velocities. In the course of the experiments the lateral position of the tubes with respect to each...

CO2 methanation was studied in the presence of nickel catalysts obtained by the solid-state combustion method. Complexes with a varying number of ethylenediamine molecules in the coordination sphere of nickel were chosen as the precursors of the active component of the catalysts. Their synthesis was carried out without the use of solvents, which ma...

This work reports an experimental and kinetic modeling investigation on flame chemistry of propene at elevated pressures. The chemical structures of premixed propene/O2/Ar flames at 2–5 atm and the equivalence ratio of 1.5 including reactants, major products and a series of intermediates were measured using the flame sampling molecular beam mass sp...

Improving the fire resistance of polymeric materials is an important research problem, which is solved using various flame retardants. Organophosphorus compounds are among the most effective and environmentally friendly flame retardants. This paper reports an experimental, theoretical, and kinetic modeling study of the conversion of triphenyl phosp...

This work describes the mathematical modeling of the thermal decomposition of the complex compound [Ni(En)3](ClO4)2 (En = C2H8N2 = ethylenediamine) in an inert atmosphere under non-isothermal conditions. This process is characterized by several simultaneous and intense stages: elimination of ethylenediamine from the nickel coordination sphere, deco...

The paper presents the results of experimental studies of scenarios of diffusion combustion of a microjet of hydrogen flowing out of a cylindrical micronozzle with a diameter of 200 μm. The hydrogen microjet is ignited near the nozzle exit and at a distance. The experimental data are compared with the data previously obtained, and the results are e...

1,2-Propylene oxide (PO, C3H6O) is considered as a promising agent for improving fuel. In this work, the effect of PO additives on the species pool in a premixed burner-stabilized fuel-rich (ϕ = 1.6) flame fueled by n-heptane/toluene mixture (7/3 by volume of liquids) at atmospheric pressure is studied by the flame-sampling molecular beam mass spec...

The project of the station of synchrotron radiation of the second stage Plamya-2 for the Siberian ring photon source SKIF is based on the experience gained during the development of the station "Plamya" on the storage ring VÉPP-4 at the Siberian Center for Synchrotron Radiation (SR). The station is designed to study the processes of combustion and...

As a result of the interaction of nickel perchlorate with ethylenediamine, imidazole, and semicarbazide, complex compounds Ni(En)3(ClO4)2, Ni(Im)6(ClO4)2, and Ni(SC)3(ClO4)2 have been obtained, the structure and composition of which were confirmed by elemental analysis and by the method of the infrared spectroscopy of frustrated total internal refl...

Ketene is an important species in core mechanisms for the combustion of hydrocarbon and oxygenated fuels, but direct experiments with ketene are challenging to conduct due to its high reactivity. Diacetyl can be used as a precursor of ketene, and abundant ketene is present in premixed flames of diacetyl. However, predictions of ketene in diacetyl f...

Because it is a carbon free fuel with high volumetric and gravimetric hydrogen density, ammonia is considered to be a promising hydrogen carrier molecule; its combustion chemistry, consisting of ammonia and ammonia/hydrogen blends, are of great importance in engine and gas turbine systems. This paper presents experimental data and kinetic modeling...

In the present review, using an integrated approach based on the experimental and theoretical study of the processes of thermal decomposition and combustion of practically important polymers, such as polymethyl methacrylate, polyethylene, and glass-fiber-reinforced epoxy resin, the features of the mechanism for reducing the combustibility of these...

The solid-state combustion method was used to prepare nickel-based catalysts for CO2 hydrogenation from [Ni(C3H4N2)6](NO3)2 and [Ni(C3H4N2)6](ClO4)2. These complexes were synthesized by adding nickel nitrate and perchlorate to melted imidazole. The composition and structure of the obtained complexes was confirmed by ATR FTIR, powder XRD, and elemen...

Gas-phase combustion of methylmethacrylate (MMA) monomer is an essential stage of solid polymethylmethacrylate (PMMA) combustion, which is of interest in many applications. A skeletal kinetic scheme for MMA combustion in air is proposed including 44 irreversible elementary reactions for 29 species. The mechanism is derived from the reduced kinetic...

Three-dimensional simulations of laminar flame propagating downwards the vertical surface of a rigid polyurethane slab heated by a radiative panel are presented and compared with the measurement data. The gas-phase model (ANSYS Fluent) allows for finite-rate volatile oxidation, soot formation and oxidation, emission, transfer, and absorption of the...

The search of alternative fuels is one of the most important issues. Hydrogen is the most attractive one since its combustion products include only water. However, due to its specific properties wide implementation of hydrogen is not possible. There is an idea to use chemical carriers of hydrogen, for example, ammonia. The addition of hydrogen, whi...

Understanding the ion chemistry in flames is crucial for developing ion sensitive technologies for controlling combustion processes. In this work, we measured the spatial distributions of positive ions in atmospheric-pressure burner-stabilized premixed flames of ethylene/oxygen/argon mixtures in a wide range of equivalence ratios ϕ = 0.4÷1.5. A fla...

For the first time, next to the flammability tests (LOI, UL-94 HB, VBB, TGA), experimental tests and computer simulation have been conducted on the flame spread and combustion of glass fiber-reinforced epoxy resins (GFRER) with 6% graphene and 6% DDM-DOPO flame-retardant additives. The downward rates of flame spread (ROS) in opposed flow with oxidi...

The spatial distributions of naturally occurring cations in near-stoichiometric (equivalence ratios ϕ = 0.8 and 1.2) burner-stabilized methane/oxygen/argon flames at atmospheric pressure are studied by molecular beam mass spectrometry (MBMS) and kinetic modeling. The disturbing effect of a nickel sampling cone used in the measurements on the flame...

The popularity of organic polymers despite their high flammability forces the introduction of flame retardants (FR) such as metal phosphinates into the combustible material. The thermal behavior of aluminum diethylphosphinate (AlPi) as FR in the widely used polymer ultra-high molecular weight polyethylene (UHMWPE) is investigated here. The study fo...

For the first time, a comprehensive study of downward flame spread over glass-fiber-reinforced epoxy resin (GFRER) slabs in oxidizer flow has been carried out experimentally and numerically. Microthermocouples were used to measure the temperature profiles on the solid fuel’s surface and in the flame, and a video camera was used to measure the rate...

One of the most important problems of modern energy industry is the transition to carbon free fuels, which can mitigate the negative environmental effects. This paper presents experimental data on ammonia and ammonia/hydrogen blends oxidation in an isothermal jet-stirred reactor over the temperature of range 800–1300 K. Experiments were performed u...

Systematic experiments and complementing numerical simulations have been reported for the first time to understand the spread of a ground fire over pine needle bed of the Siberian boreal forests (Pinus silvestris) in still air. Using equipment and instrumentations specifically developed for the purpose, careful experiments have been conducted to re...

Experimental study and three-dimensional simulation of warming up, ignition, and subsequent burning out of the composite material impacted by the attached Bunsen burner flame is presented. The specimen is the fiberglass-reinforced composite with the epoxy resin binder. In the experiment, vertical specimen was located above the laminar diffusion fla...

The article presents qualitative data on the study of the process of diffusion combustion during the outflow of a gas jet from a nozzle apparatus with a certain arrangement of nozzles. The nozzle apparatus is a round nozzle with a straight channel and a coaxially located annular slot. In the experiments, hydrogen or methane was supplied through an...

For the first time, on the basis of a systematic experimental study of the propagation of a model ground fire over pine needles bed at a low wind speed (in the range of 0.1 m/s—0.4 m/s), in which there have been no measurements reported so far, a nonlinear dependence of flame spread rate on the wind speed has been established. Further, the total he...

This paper presents a method for determining the optimal (in terms of fire-suppression effectiveness) composition of synergistic binary fire suppressants consisting of a chemically active inhibitor (e.g., trimethylphosphate) and an inert diluent (CO2). The method is based on the numerical simulation of the speed and structure of one-dimensional pre...

This paper presents experimental data on the flame structure of laminar premixed ammonia and ammonia/hydrogen flames at different equivalence ratios (φ = 0.8, 1.0 and 1.2) and the laminar flame speed of ammonia/hydrogen flames (φ = 0.7–1.5) at 1 atm. Experimental data were compared with modeling results obtained using four detailed chemical-kinetic...

This work reports investigations on laminar premixed ethylene (C2H4) flames with special interests on measurements and kinetic modeling at elevated pressures. Chemical structures of laminar premixed C2H4/O2/Ar flames at 3 and 5 atm with the equivalence ratio of 1.4 were measured with molecular beam mass spectrometry. Both the stable and reactive sp...

In the present study, downward flame spread over multiple parallel fuel sheets is investigated experimentally and numerically to understand the mechanism that controls the flame spread process and compare that with the flame spread over a single fuel sheet. A 2D numerical model, based on OpenFOAM is used to simulate the flame spread in a natural co...

The results of experimental investigations of the features of diffusion combustion during the interaction of a round supersonic microjet of air in the center and a coaxial (coflowing ring) jet of hydrogen. Such combustion is accompanied by a number of new phenomena: the formation of a cone-shaped flame near the nozzle сutoff, the locking of the com...

Ethyl pentanoate (EPE) or ethyl valerate is considered a surrogate for biodiesel fuels and a potential fuel for spark ignition engines. Knowledge of its combustion chemistry is of great importance for the development of high-performance and environmentally friendly combustion devices fueled with biofuels. In this work, a detailed chemical kinetic m...

Studies have been carried out on the effectiveness of the action of two types of fire retardants – graphene and an organic phosphorus-containing compound DOPO-THPO, introduced into an epoxy resin. The amount of fire retardants introduced was 0; 2 and 4% of the amount of epoxy resin. The efficiency was assessed by the oxygen index method (LOI). It w...

Studies have been carried out to assess the effectiveness of fire retardants on the flammability of an epoxy composition – graphene and an organophosphorus compound DOPO-THPO. The concentrations of the added flame retardants were 2 and 4 % (mass). Flammability characteristics were determined using the method according to GOST 28157 (UL 94) with ver...

Experimental data are presented on the effect of inert (He, N2, Ar, CO2) and reactive (SH4, O2, CF3Br, (CH3O)3PO) gas additives to hydrogen flow and ambient air on flame separation during diffusion combustion of a hydrogen microjet emanating from a round micronozzle into air. The micronozzle is a stainless steel tube with an inner diameter of 0.5 m...

Spatial distributions of positively charged species naturally occurring in the stoichiometric and fuel-rich premixed H2/CO/O2/Ar flames are measured with molecular beam mass spectrometry. The hydronium (H3O⁺) ion and its clusters are found to be most abundant cations in the flames. The ion chemistry model proposed earlier by Belhi et al. (2018) for...

Flame structure of laminar premixed HC(O)OH/O2/Ar was studied both experimentally and numerically. Three available chemical kinetic models were tested. In general, all models agree with experimental results for H2O, CO, O2, CO2, HC(O)OH within the experimental error. For most of the intermediates all the models well capture the peak position and co...

This work represents a detailed investigation of combustion and oxidation of methyl-3-hexenoate (CAS Number 2396-78-3), including experimental studies of combustion and oxidation characteristics, quantum chemistry calculations and kinetic model refinement. Following experiments have been carried out: Speciation measurements during oxidation in a je...

This paper presents experimental data on the effect of inert (He, N2, Ar, CO2) and reactive (СН4, O2, CF3Br, (CH3O)3PO) gas additives to hydrogen and ambient air on flame blow-off during diffusion combustion of a hydrogen microjet emanating from a micronozzle into air. It is found that the addition of the above gases to hydrogen narrows the microje...

This study presents careful measurements from lab-scale experiments and predictions from comprehensive numerical model for the burning characteristics of laminar flames over MMA pools of different diameters with varying ullages or lip heights. Lab-scale experiments for steady burning of MMA pool are conducted, and temperature and concentrations of...

The knowledge of the combustion chemistry of oxygenated fuels is essential for the development of detailed kinetic mechanisms suitable for the combustion processes involving biofuels. Moreover, epoxidized olefins, are increasingly used as chemical intermediates or as bulk chemicals. Nevertheless, a dearth of data for their reactivity in the oxidati...

Experimental and numerical studies of downward flame spread over polymethyl methacrylate (PMMA) with and without addition of triphenyl phosphate (TPP) are reported. Using the micro-thermocouple technique and molecular beam spectrometry, detailed flame structures of PMMA and PMMA+10%TPP were measured. From the experiments and quantum chemistry calcu...

The work presents an experimental and kinetic modeling study of laminar premixed formic acid [HC(O)OH]/H2/O2/Ar flames at different equivalence ratios (φ=0.85, 1.1 and 1.3) stabilized on a flat burner at atmospheric pressure, as well as laminar flame speed of HC(O)OH/O2/Ar flames (φ=0.5–1.5) at 1 atm. Flame structure as well as laminar flame speed...

The effect of triphenyl phosphate (TPP) retardant inhibition on flame propagation over the horizontal surface of polymethyl methacrylate (PMMA) has been studied experimentally and numerically. Regarding the flame spread behavior over the surface of PMMA (pure and inhibited by TPP), the following parameters were measured: thermal decomposition with...

A comprehensive study of thermal decomposition and combustion of a horizontally placed polyoxymethylene (POM) slab was performed. The kinetic parameters of thermal degradation of POM in supposition of two parallel reactions were determined and were used for simulation of the flame spread over the POM. The following main characteristics of the POM s...

Mole fraction profiles for reactants, major products, and main combustion intermediates were measured in near-stoichiometric and fuel-rich premixed burner-stabilized flames of ethyl acetate (AcOEt) under atmospheric pressure. Three recent chemical kinetic mechanisms for the AcOEt combustion were validated against the data reported. Their different...

Elaboration of a predictive and well validated kinetic mechanism for combustion of H 2 /CO mixtures is the key to development of advanced technologies for effective syngas burning in power generation systems. Moreover, understanding the combustion chemistry of H 2 /CO mixtures is a prerequisite for a comprehensive description of hydrocarbons chemis...

In the present paper we show our recent experimental data on diffusion combustion of a round hydrogen microjet in a cocurrent flow of air mixed with nanoparticles of TiO2. The hydrogen microjet is emanated from a round micronozzle which is surrounded by a coaxial slit to produce the cocurrent flow. Combustion events found in the present conditions...

Experimental data on combustion of a round hydrogen microjet in a cocurrent coaxial air jet are presented. As is found, the combustion of microjet is dominated by the generation of “bottleneck-flame region” that is in agreement with our previous observations on the diffusion combustion of subsonic hydrogen microjets. Transformation of the spherical...

The paper presents the results of measuring the propagation velocity and Markstein length of pure and inhibited laminar axisymmetric dimethyl ether/air flames using the PIV method. Their dependence on equivalence ratio and the concentration of inhibitor is studied. Trimethyl phosphate is used as an inhibitor. The measurement results show a strong d...

Experimental data on the diffusion combustion of round hydrogen microjet in concurrent coaxial flows are presented. The effects on combustion of the concurrent flow of air and that of air premixed with nanopowder of TiO 2 are of interest. The hydrogen microjet is emanated from a round micronozzle which is surrounded by a coaxial slit to produce the...

The objective of the present work is experimental investigation of diffusion combustion of a plane hydrogen microjet emanating from a slotted micronozzle at subsonic and supersonic velocities. Four scenarios of the supersonic microjet combustion are presented including that in the presence of supersonic cells. It is shown that the subsonic combusti...

The burning behavior of polyoxymethylene in the counterflow of oxidizing air has been studied experimentally and numerically. Measurements have been performed using a specially designed burner. The temperature profiles were measured in gas phases by a microthermocouple technique. The burning surface temperature and the mass burning rates of solid f...

For diesel engines, dimethyl ether (DME) is widely used in the world, it is a perspective candidate to replace traditional diesel in the future. The consumption of DME as a motor fuel is constantly increasing. DME has a very low propensity to soot formation during combustion, which allows not only to reduce harmful emissions into the atmosphere, bu...

In this paper, we presented the results of experimental studies of the diffusion combustion of a plain hydrogen microjet flowing from a slit micronozzle at subsonic and supersonic speeds. For the first time, four scenarios of diffusion combustion of a plain hydrogen microjet including supersonic combustion in the presence of supersonic cells in bot...

The effect of adding isomeric esters ethyl pentanoate (EPe) and methyl hexanoate (MHe) to a model diesel fuel on the chemical structure of its flame has been investigated. A 7/3 (vol) n-heptane/toluene mixture was used as a model diesel fuel. The concentration of EPe or MHe additives to the n-heptane/toluene mixture was 50 vol %. The studied flames...