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A kinetic model for the ignition and combustion of mixtures of propane and n-butane in the air has been developed. The model contains 348 reactions involving 72 species and includes both a high and low-temperature mechanism of propane and n-butane oxidation. The kinetic model was tested against experimental data on the ignition delay time and laminar flame speed. The model provides a good fit to experimental data on propane ignition and the laminar flame speed in propane-air mixtures, ignition of n-butane under different initial conditions (T₀ = 670 ÷ 1 550 K, ρ₀ = 1 ÷ 30 atm, φ = 0.3 ÷ 2.0), laminar flame speed in mixtures of n-butane with air at T₀ = 298 K, ρ₀ = 1 atm, and various stoichiometric ratios φ= 0.67 ÷ 1.5), as well as on the ignition of stoichiometric C₃H₈/C₄H₁₀/N₂/Ar mixtures with different relations C₃H₈/C₄H₁₀ at T ₀ = 710 ÷ 910 K and ρ₀ = 17.8 atm. The developed kinetic mechanism was used to perform a demonstration numerical simulation of combustion of propane-butane fuel in a homogeneous combustion chamber

This paper describes an experimental study of combustion initiation in a supersonic flow of a hydrogen-air mixture under the simultaneous action of focused pulse-periodic CO₂ laser radiation and an external electric field. Combustion in a supersonic jet is studied on the basis of data on the intrinsic glow of a flame at the radiation wavelengths of excited OH^* radicals. Mixture combustion initiation depends on the shape of electrodes and electrical signals. The flame that occupies the entire cross section of an air-fuel jet is observed only under the conditions of simultaneous action of laser radiation and an electric field. Thus, the combined use of optical and electrical discharges makes it possible to initiate combustion and stabilize the flame of a hydrogen-air mixture in a supersonic flow without mechanical stabilizers.

This paper presents a mathematical model of combustion of a coal dust particle-gas suspension in a methane-air mixture, which takes into account the inhomogeneity of temperature distribution in the particles. The particle-gas suspension state parameters are determined by the model of the dynamics of a two-phase two-velocity reacting gas-dispersed medium. The combustion of coal dust particles is simulated using a local mathematical model of a heterogeneous reaction on the particle surface and particle heating. A solution to local problems of coal dust particle combustion is used determine the heat release rate of the entire set of particles in the heterogeneous reaction of coal dust with oxygen and the heat exchange with gas. Dependences between the combustion front propagation velocity and the mass concentration of coal dust and the volumetric concentration of methane are determined. The estimated combustion front velocity in a methane-air mixture with no coal dust is in good agreement with experimental data. The comparison of calculating the flame velocity in a coal-methane-air mixture using two models (with and with no account for the inhomogeneity of the temperature distribution in the particles) is given. This comparison shows a significant difference in the values of the estimated combustion front velocity of rapidly burning gas-particle suspensions. For slowly burning particle-gas suspensions, this difference decreases. The developed model explains the shift of the maximum flame propagation velocity in the coal-methane-air mixture toward the excess of fuel in air.

Flame propagation over a thin film of various liquid fuels with an ignition point below the ambient temperature was experimentally studyied. The study was carried out on thin copper and thick glass substrates in media with different oxygen concentrations. It is shown that with an increase in the oxygen concentration, the flame speed increases faster than the normal speed of the corresponding homogeneous stoichiometric mixture. When the proportion of oxygen in the mixture with nitrogen changes from 0.21 (air) to 1, the flame speed range is 0.02 ÷ 2.4 m/s. At flame propagation speeds above 0.3 m/s, the condition of thermal thinness is not satisfied even for thin copper substrates. The flame speed ceases to depend on the properties of the substrate and the fuel layer thickness and becomes dependent only on the properties of the fuel. In this speed range, the flame propagation speed increases linearly with an increase in the thermal effect of a unit volume of a stoichiometric mixture of fuel vapor with oxidizer and decreases with an increase in the difference between the temperature T_st at which the stoichiometric composition is formed under equilibrium conditions and the ambient temperature T₀.

Spray ignition is widely encountered in energy and power engineering and is an important characteristic in combustor operation and design. Droplet ignition is an important part of spray ignition. Most present studies of droplet and spray ignition use numerical simulation, which sometimes cannot explicitly indicate the mechanism of ignition and is inconvenient for engineering applications. This paper reports experimental and analytical studies on ignition of a single droplet and spray under different flow conditions. Analytical results based on a one-dimensional model are compared with experimental results. The results reveal that the droplet ignition temperature decreases with an increase in the droplet size and increases with an increase in the relative gas velocity. The temperature of kerosene spray ignition by propane combustion products increases with an increase in the excess air and decreases with an increase in the droplet size. The obtained research results are useful for liquid-fueled combustor design and operation.

The thermal decomposition of bis-R-substituted gem-dinitroethyl-N-nitramines in diphenyl ether solution was studied by a manometric method in combination with mass spectrometry and photoelectric colorimetry. The reaction proceeds according to the first order equation and is not complicated by chain and heterogeneous processes. The rate-determining step of the process is the homolysis of the C-NO₂ bond in the gem-dinitro group. The kinetic parameters of the rate-determining step were determined. The influence of the structure on the reactivity of the investigated compounds was analyzed. Linear relationships were found between the rate constant, the activation energy of thermal decomposition, and the steric constants of the α-substituent of the reaction center.

In the paper under discussion, O.A. Kozyreva claims that D. Kaplan’s semantics of indexicals needs a modification because it cannot explain some controversial cases of communication. She also argues that the needed modification of Kaplan’s semantics entails a revision of the distinction between semantics and pragmatics. The author objects to the first claim, which also calls into question the second one. His objection is that Kaplan’s semantics supplemented by some pragmatic ideas successfully explains “controversial” cases of communication.

In their articles on the distinction between semantics and pragmatics of natural language, O.A. Kozyreva and E.V. Borisov present polar opinions. There is also an intermediate position (it is defended, in particular, by J. Perry), according to which there are reasons to maintain the distinction between semantics and pragmatics, but the number and set of semantically significant context factors can be radically expanded by including factors such as language. Therefore, the concept of semantic meaning is also expanded; it is proposed to be defined as a set of propositions and propositional functions that express the conditions for the statement truth, depending on the context. The article presents arguments in favor of such a position.

The article considers the application of the “semantics with an agent” and “semantics without an agent” proposed by O.A. Kozyreva to mathematical sentences. If it is possible to prove that mathematical sentences are context-dependent, these sentences will need semantic interpretation along with other context-dependent sentences. The author presents an interpretation of mathematical sentences as context-dependent by appealing to the epistemic contextualism and the epistemology of computer proof. Based on this interpretation, he argues that the understanding of semantics as “semantics with an agent” is compatible with the thesis of context dependence of mathematical sentences, while the understanding of semantics as “semantics without an agent” will require additional formalization of pragmatic factors to achieve compatibility with such sentences.

The article presents the author’s comments on the remarks of the discussants and her answers to some of their criticisms.