Nanocluster initiation of combustion of off-grade hydrocarbon fuels

We have performed large-scale experiments on burning, in the regime of nanocluster pulsating combustion, such off-grade fuels as straw oil, hydrocarbon fuel, exhaust crankcase waste, crude oil, and others on the laboratory prototype of the self-contained burner of the Institute of Thermal Physics, Siberian Branch of the Russian Academy of Sciences. The application of modern diagnostics has made it possible to obtain a large body of information on the features of the physicochemical processes of such combustion in the presence of superheated steam. The experimental and theoretical studies have shown that as a result of the heterogeneouscatalytic decomposition of water molecules on soot nanoclusters in the mixing zone, high concentrations of the OH radical are formed and that this decomposition can be effective on carbon particles of size 1–5 nm at temperatures characteristic of traditional flares. The generation of an active OH radical leads to a significant increase in the rates of chemical reactions and a stable high-temperature combustion of "heavy" fuels with the observance of ecological norms.     

Turbulent combustion of gaseous fuels

Differences and similarities between the parameters of turbulence and turbulent viscosity of an isothermic jet and a burning-fuel torch have been analyzed on the basis of experimental data. It is proposed to use the dependences obtained for calculating the temperature fields in torches of gaseous fuels.     

Studies of combustion and heat-transfer processes in a combustion flame in a melt

With a specially developed zonal mathematical model theoretical studies of heat transfer processes in a combustion flame immersed into a melt were carried out in steady-state conditions. As a result of this analysis, including the main phenomena which take place in gaseous fuel burning in the melt, the temperature and heat flux distributions between different phases over the melt height were found. The effect of convective heat transfer on the heat-transfer processes between the melt and the immersed combustion flame was determined.Notation convective heat-transfer coefficient W/(m²·K) - F interface area, m² S. M. Kirov Urals Polytechnical Institute, Ekaterinburg, Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 64, No. 3, pp. 293–296, March, 1993.     

Heat exchange during the forced flow of hydrocarbon fuels at supercritical pressures in heated tubes

Heat transfer coefficients have been measured during the turbulent flow of hydrocarbon fuels at supercritical pressures under conditions in which no deposits occur. It is shown that a regime of impaired heat exchange can occur when the stream and wall temperature values are lower than the pseudocritical temperature of the fuel. The boundaries of this regime are established and empirical relationships are proposed for calculating the impaired and normal heat exchange.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 60, No. 1, pp. 46–50, January, 1991.     

Some unique features of heat liberation in boiling of hydrocarbon fuels in large volume

Heat liberation coefficients are measured for boiling of hydrocarbon fuels in large volume at pressures up to 0.31 MPa. It is established that oxygen dissolved in the fuels encourages formation of precipitates and affects heat exchange during boiling. The dependence of the heat liberation coefficient upon thermal flux and pressure is presented for bubble bailing of deoxygenated fuels.Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 59, No. 4, pp. 583–586, October, 1990.     

Mixture of fuels approach for the solution combustion synthesis of LaAlO3 nanopowders

A modified solution combustion approach was used in the preparation of nanosize LaAlO₃ (～23.6 nm) using mixture of citric acid and oxalic acid as fuels with corresponding metal nitrates. The synthesized and calcined powders were characterized by Fourier transform infra red spectrometry (FTIR), Differential thermal analysis-Thermogravimetry analysis (DTA–TGA), X-ray diffractometry (XRD) and Transmission electron microscopy (TEM). The FTIR spectra show the lower frequency bands at 656 and 442 cm^?1corresponds to metal–oxygen bonds (possible La–O and Al–O stretching frequencies) vibrations for the perovskite structure compound. DTA confirms the formation temperature of LaAlO₃ varies between 830–835 °C. XRD results show that mixture of fuels ratio is influential on the crystallite size of the resultant powders. The average particle size of LaAlO₃-1 as determined from TEM was about 41 nm, whereas for LaAlO₃-2 and LaAlO₃-3 samples, particles are seriously aggregated.     

Influence of fuels and combustion aids on solution combustion synthesis of bi-phasic calcium phosphates (BCP)

The possibility to obtain biphasic HA/TCP composite by solution combustion synthesis method using urea and glycine as fuels was investigated. Calcium nitrate was taken as a source of calcium, and diammonium hydrogen phosphate served as a source of phosphate ions. Nitric acid and nitrate ions were used as oxidizers. The effect of the nature of fuel (urea and glycine) and fuel to oxidizer ratio on the combustion behavior, as well as, chemical composition and morphology of as-formed powders was investigated. It was found that only monoclinic-TCP was formed in the combustion end-product when glycine was used. In contrast to this, the use of certain amount of urea led to the formation of rhombohedral-TCP. A series of combustion reactions were carried out to study the influence of fuel to oxidizer ratio on HA to TCP ratio in synthesized product.     

Hydrophilicity of soot particles formed in the combustion chamber of a jet engine

The particles of soot, formed in the combustion chamber of a jet engine under conditions typical of a cruising power mode, are capable of adsorbing a considerable amount of water vapor owing to their microcrystalline structure, microporosity, and chemically heterogeneous surface.     

Kinetic models of combustion of kerosene and its components

Modern investigations on creation of kinetic models of combustion of hydrocarbons entering into the composition of kerosene and kerosene as a whole have been analyzed. Certain recommendations on application of these models to calculation of actual gasdynamic flows have been given. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 6, pp. 14–25, November–December, 2005.     

Numerical simulation of processes in a spherical combustion chamber

A theoretical model of gasdynamic and mechanical processes in a spherical explosion chamber is considered. Comparison of numerical results obtained with this model with calculated and experimental results of other authors shows good agreement.Translated from Inzhernerno-Fizicheskii Zhurnal, Vol. 47, No. 4, pp. 657–662, October, 1984.     

Kinetic study of trichloroethylene combustion on exchanged zeolites catalysts

In this paper is presented a kinetic study of the catalytic combustion of trichloroethylene (TCE) over Y-zeolites exchanged with several cations. The catalysts, based on zeolite, were prepared by ion exchange and characterized by means of physico-chemical techniques and then tested under kinetic conditions. The kinetic results obtained were interpreted using kinetic models of power-law type and Eley-Rideal. The results obtained indicate that catalyst Y-Cr is more active than Y-Co catalyst. The greater activity of catalyst exchanged with Cr can be attributed to the higher acidity that presented these catalysts.     

Effect of the PLAZMAZER plasma ignition system on the fuel combustion regimes in combustion chambers of engines

An economically efficient method of combatting toxic products of incomplete fuel combustion in engines and other movable and stationary power installations by means of pulsed automatic control of the ignition and combustion processes carried out by the PLAZMAZER system is proposed. A new concept of the occurrence of motor knock in internal combustion engines with external carburetion, the stiff operating mode of diesel engines, erosion of turbine blades, burn-out of combustion-chamber and exhaust-line elements, and jet engine compression stalling are presented.     

Thick-film nitrogen-monoxide sensors for analysis of the combustion products of organic fuels at heat-and-power plants

The method of metal-screen printing is used to obtain thick films of WO₃ that are highly selective to NO. The films are then used to make nitrogen monoxide sensors that can detect concentrations of (5–1000)·10⁻⁶ while operating at temperatures within the range 175–300°C. A prototype of a system for continuously monitoring NO in power-plant emissions has been designed and built. Translated from Izmeritel'naya Tekhnika, No. 1, pp. 34–36, January, 1997.     

Distinctive features of operation of an internal combustion engine running on hydrogen-containing fuels

Experimental investigations have been carried out on an internal combustion engine with hydrogen added to the hydrocarbon fuel, i.e., gasoline. The possibility of improving the energy and environmental indices in the case of hydrogen feed to the engine’s air path has been shown. It has been established that increase in the fraction of hydrogen in the fuel mixture causes the operating process of the engine to improve, with the result that the flow rate of gasoline as a function of the H₂ fraction decreases by nearly 70%. Considerable reduction in the content of CO, CO₂, and CH (of approximately 5–60% depending on the amount of the added H₂) is observed. However, adding hydrogen to the fuel-air mixture leads to an increase in the content of nitric oxides in the combustion products because of the growth in the velocity of propagation of the flame and increase in the combustion temperature.     

Heat effect of the oxygen-containing functional groups in coal during spontaneous combustion processes

The heat generated from the reactions of oxygen-containing functional groups in coal has been studied using organic chemistry and quantum chemistry analysis methods. Structural models of the oxygen-containing functional groups in coal were established and used to analyze the reactions of these groups during spontaneous combustion. The Gibbs free energy and enthalpy changes associated with these reactions were determined using quantum mechanical analysis, and the results indicated that the dehydration and dehydrogenation reactions of the hydroxyl groups in coal were only mildly exothermic, whereas reactions involving the oxidation of the carbonyl groups were much more exothermic. In contrast, reactions resulting in the generation of carbon monoxide were endothermic. By comparing the heat release characteristics of the reactions of the oxygen-containing functional groups with the levels of oxygen consumption and gas production, as well as temperature profiles of the reactions, it was concluded that the decomposition of oxygen-containing functional groups is critical to the production of heat during the initial stages of the spontaneous combustion of coal and that oxidation does not occur during this period. These results also explain why the temperature of coal rises slowly during the initial stages of its spontaneous combustion.