SCIENCE & EDUCATION

A mathematical model of the liquid flow in heterogeneous systems is developed. Heterogeneous systems consist of a porous body with the pore size from 20 nm to 360 nm and a lyophobic (non-wetting) liquid. The paper represents theoretical basics to describe a hysteresis of liquid filling and outflow processes from the pores under the pressure gradient, and also with no liquid outflow after reducing a pressure in the system to the atmospheric value under static and dynamic loads. The paper presents experimentally investigated and calculated results of the energy characteristics of models of the heterogeneous dissipation and accumulating devices of mechanical energy developed on the basis of abovementioned effects.

Influence of methane on diffusion auto-ignition of hydrogen during pulsed discharge escape to the air from a high-pressure chamber was experimentally determined. Pulsed discharge occurred from a high-pressure chamber due to a breakup of the diaphragm. Hydrogen was mixed with air at the contact border. In this case hydrogen ignition point was achieved by means of air heating with a created shock wave which occurred as a result of non-stationary hydrogen discharge from a high-pressure chamber. It was shown that increase in the amount of methane led to increase in the delay of ignition. It was proposed that there is a kinetic mechanism of inhibition of burning in addition to a thermal process. The obtained results could be used for preventing hydrogen ignition in storage and while operating in high-pressure systems.

In this article the authors propose methods of quantitative estimation of the processes’ gas-dynamic parameters in gaseous media, based on the results of optical recording. The basis of this technique is a well-known dependence of a directly proportional relationship between the brightness of the image and the second derivative of gas flow density with respect to the coordinates. Comparison of experimental and calculated data showed that the developed method allowed to perform a quantitative estimation of the processes’ gas-dynamic parameters in gaseous medium correctly. It leads to a significant increase in the number of possibilities of optical registration of aero-physical and ballistic experiments and makes these experiments cheaper and simpler.

The article covers workability of the density functional theory in systems consisting of two subsystems which include two various types of Fermi particles. At the description of similar systems, in particular, molecules and nanoclusters, the density functional method is carried out in the assumption that system properties can be described while considering the basic condition of non-uniform electronic gas moving in the potential created by motionless nuclear kernels. In this work it was shown that such an approach results in an error in definition of the basic energy of the system. Ways of quantitative estimation of this error were specified.

The paper considers problems of complex experimental research of high-beat states of electrode assemblies for electroarc devices working in a wide range of controlled environment pressures. The author describes methods and means of diagnostics of devices with hot cathodes (models with hollow cathode and with tungsten core cathode).  The experimental setup consisted of different diagnostic equipment which allowed to determine both local and integral thermophysical characteristics of the voltaic arc, namely: high temperature of the cathode (up to 3000 K) and its longitudinal distribution, large heat fluxes into the anode (QA ≥ 1 kW) and its distribution on the working electrode surface. The results of diagnostics of electrodes thermal states were discussed, and recommendations on their use in technological electroarc devices were given in this article.