Showing papers by "Evgeny Shafirovich published in 2001"
TL;DR: In this paper, an experimental setup with an electrodynamic levitator inside a high-pressure chamber was employed for heating to ignition of single particles of magnesium and aluminum in carbon dioxide at pressures 0.1-2 MPa.
Abstract: This article considers ignition and combustion of single particles of magnesium and aluminum in carbon dioxide at pressures 0.1-2 MPa. An experimental setup with an electrodynamic levitator inside a high-pressure chamber was employed. The CO2-laser was used for heating to ignition of the particles. The results show that ignition mechanisms of Mg and Al in CO2 are different. Experiments with Mg indicate the existence of the critical partial pressure of CO2, whereas the ignition probability of Al particles in CO2 is low but independent on pressure. Analysis of flame images and combustion parameters shows that the mechanism of Mg particle burning in CO2 corresponds to conventional models of vapor-phase diffusion-controlled combustion, whereas in the case of Al exothermic processes on the particle surface or close to it play a leading part in the burning process.
68 citations
TL;DR: In this article, it was shown that combustion mechanisms of magnesium in C02 are identical in the range of particle sizes 0.05-5 mm for stable combustion regime, the burning times measured in micro gravity follows a quadratic dependence with the particle size, which is typical for the diffusion-controlled combustion.
Abstract: Magnesium particles (1-2 mm) are ignited by a hot wire in room-temperature C02 environment under microgravity and normal gravity conditions. In about 50% of experiments, regardless of the gravity level, a pulsating combustion regime is obtained which may be associated with the relatively low heat release in such oxidizer as C02 and high heat losses. For stable combustion regime, the burning times measured in micro gravity follows a quadratic dependence with the particle size, which is typical for the diffusion-controlled combustion. Good quantitative agreement with previous data obtained for particles of different sizes indicates that combustion mechanisms of magnesium in C02 are identical in the range of particle sizes 0.05-5 mm.
7 citations
21 Feb 2001
TL;DR: In this paper, a combustion facility for the International Space Station is proposed, which would make it possible to study high pressure combustion of spray and clouds as well as particle clouds in high pressure conditions.
Abstract: Combustion of droplet sprays and particle clouds is a very important area due to numerous applications to engines and power systems as well as to problems of industrial safety and clean environment However, combustion of two-phase systems is not well understood yet In the combustion of sprays or clouds gravitational effects add another difficulty due to the sedimentation of the particles and droplets Indeed, stability of a spray or a cloud under normal gravity can only be achieved by stirring this two-phase mixture which produces a turbulent flow field Therefore, under normal gravity conditions, the combustion characteristics of two-phase mixtures can only be obtained in turbulent flow On the other hand, and namely for high-pressure conditions, these characteristics are in fact also strongly influenced by natural convection It is proposed to develop a combustion facility for the International Space Station, which would make it possible to study high pressure combustion of spray and clouds as well as