A kinetic model for the combustion of carbon in a porous medium

A model is proposed for infiltration combustion, which incorporates the reaction kinetics more fully. Calculations have been performed on a multicomponent system with complicated kinetics, which show that the kinetic parameters have a marked effect on the basic working ones. It has been shown by varying the water-air ratio for wet combustion that the completeness of the conversion of the fuel increases with the initial water concentration, and that the speed of the combustion front and the combustion temperature increase.Chernogolovka. Translated from Fizika Goreniya i Vzryva, Vol. 29, No. 3, pp. 136–139, May–June, 1993.     

Pressure-coefficient trends for mixed propellants

Spline fitting has been used in processing measurements on the pressure dependence of the burning rate to obtain additional information on the variation in the pressure coefficient v as affected by grain size and composition, as well as by the nature of the components. Conclusions are drawn on the burning mechanism. The peak on v(p) is due to serial-parallel conversion of APC in the condensed and gas phases and to changes in the relative significance of the chemical stages. There is a minimum at elevated pressures for many propellants, which in some cases is transformed into a plateau or inflection on account of interaction between the fuel and the oxidizing agent in the diffusion-kinetic hydrocarbon flame.Chernogolovka. Translated from Fizika Goreniya i Vzryva, Vol. 29, No. 2, pp. 68–72, March–April, 1993     

Modeling of Filtration Combustion of Carbon

The kinetics of the overall reactions of carbon gasification at temperatures up to 1600 K is studied. The kinetic characteristics of the reactions are taken into account in a distributed mathematical model of filtration combustion of carbon. By computational experiment at different values of process control parameters (the gas flow rate, the fraction of the oxidant in the gas, and the mass ratio of carbon to the inert material in the combustible mixture), it is found that, in the wave of filtration combustion of carbon under superadiabatic conditions, carbon gasification can predominately yield either CO₂ or CO.     

Mechanism and laws of combustion of composite solid propellants with a coolant

The model of combustion of a composition consisting of a quasi-homogeneous composite propellant (matrix) and coolant particles is considered. The model is based on the leading role of exothermal decomposition of the matrix and on the cooling effect of the second component by virtue of transverse heat transfer between the components in the condensed and gas phases. Formulas for combustion characteristics (temperature, burning rate, its sensitivity to pressure, and initial temperature) are derived and analyzed. The calculated dependences of these characteristics on pressure, particle size, concentration, and thermal effects of decomposition of the components show that transitional regimes with a stronger dependence of the burning rate on pressure than that of the initial propellant are reached in a certain range of parameters. An algorithm is proposed, and a parametric identification of the model on the basis of experimental data is performed. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 6, pp. 51–60, November–December, 2007.     

溶剂对RDX热分解的影响

用布氏压力计研究不同溶剂对溶液中RDX热分解的影响。影响分为加速、抑帛和无影响三种影响三种情况：在苯、萘、异辛烷中RDX热分解速率与熔融态一臻,这类溶剂对RDX热分解无影响;脂肪族芳香化合物,醚,酯,酮及醇能加速RDX热分解,粘度较大的化合物则抑制RDX热分解。     

Effect of a Gas‐Phase Reaction on the Combustion Performance of a Sandwich Layered System

This paper considers a sandwich layered combustion model (an oxidizer and a fuel) that takes into account condensed and gasphase chemical reactions and transverse heat and mass transfer. Under particular simplifications, algebraic expressions are obtained for the burning rates of the components and the temperature and concentration of gaseous reagents on the burning surface. Calculated dependences of the burning rate on the sandwich size agree with experiments.     

Filtration combustion of a carbon-inert material system in the regime with superadiabatic heating

Superadiabatic regimes of combustion of carbon mixed with an inert solid with filtration of the steam-air mixture are studied theoretically and experimentally. The temperature in the combustion wave and the composition of gaseous products are obtained as functions of the fraction of carbon in the fuel and the amount of steam in the gaseous oxidant. In the examined range of the control parameters, the maximum temperature in the combustion wave is shown to depend only slightly on the fraction of carbon in the mixture and the amount of steam in the oxidant gas. Simulations of filtration combustion of carbon with allowance for the kinetics of its oxidation are in good agreement with experimental results. The calculated combustion temperature coincides with that measured in experiments. In calculating the composition of the gaseous products, coincidence with experimental data is observed only for particular compositions with the mass content of carbon under 60%. As the fraction of the fuel exceeds 60%, the yield of CO and H₂ increases in experiments, though such a behavior is not predicted by the theoretical analysis. Hypotheses on the reasons for the disagreement in results are put forward and experimentally checked. __________ Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 3, pp. 30–38, May–June, 2008.     

High-precision estimation of the time of arrival of radio signals

An interpolation algorithm of high-precision estimation of the time of arrival of radio signals has been proposed. Analytical expressions were obtained for specifications of the algorithm that were corroborated by the results of computer simulation. It was shown that with due regard for the complexity adequate to a receiver of the maximum likelihood estimation of the temporal position with quantized output, the proposed interpolation algorithm ensures the noise immunity close to potentially attainable. The performed analysis makes it possible to select parameters of the estimation algorithm in a reasonable way depending on the requirements to its accuracy and complexity of realization.