Volume 26, Nº 3 (2025)

The objective of this work is the computational and experimental assessment of the effect of twisting an active-reactive type projectile-piercer around its own axis on the parameters of its motion and the depth of penetration into the soil. Research methods: the equations of motion of a rotating active-reactive type projectile-piercer (SPART) are considered. The features of determining the engine thrust, rotating SPART and the resistance force during penetration of SPART into the soil with rotation are analyzed. A comparative analysis of the penetration depths of rotating and non-rotating SPART into loam is carried out. As a result of the studies, a mathematical model of the process of penetration of an active-reactive type projectile-piercer into the soil is developed. The effect of SPART rotation around its own axis of symmetry on the performance of the propulsion system is shown. The effect of contact friction forces between the rotating SPART and the soil on the parameters of its motion and the depth of penetration is assessed. Calculations show that by spinning the SPART around its own axis of symmetry, the depth of penetration of rotating active-reactive type punching projectiles into the soil can be increased by 8–10 %. Conclusion: the results presented in the article can be useful for researchers, postgraduate students and engineers involved in the creation and operation of aviation and rocket and space technology, and can also be useful for students of technical universities studying in the relevant specialties.

The work is devoted to the consideration of applications of mathematics, in particular, graph theory and group theory in chemistry and physics. Chemistry was one of the first to adopt the ideas of graph theory. Mathematical chemistry is a section of theoretical chemistry that studies the application of mathematics to chemical problems. The possibility of formalizing molecules in the language of structural chemistry using graphs allows one to determine the number of different isomers using graph theory methods. The main tool in mathematical chemistry is mathematical modeling using computer technology. The methods of graph theory are actively used in three areas of chemistry: structural chemistry, chemical kinetics, and chemical physics of polymers. Group theory has found application in many areas of physics. Group theory serves to explain the most important characteristics of atomic spectra. Group theory provides an opportunity for a uniform approach to a large number of problems in solid state physics. Matrix groups and unitary group representations are actively used in these studies. Irreducible group representations are used to classify vibrational and electronic states of a crystal. Methods of group theory are applied to models of problems of classifying electronic states of a crystal. In crystallography, much attention is paid to applications of group theory methods to the study of vibrations of atoms that make up a molecule relative to their equilibrium positions. The results can be useful in encoding information in space communications sessions.

The article presents the designs of several variants of combustion chambers for the NK-16ST engine. The combustion chamber designs are made within the framework of known concepts of low-emission fuel combustion to reduce nitrogen oxide emissions.

A serial combustion chamber with a stepped air supply along the length of the flame tube is considered. A combustion chamber with a reduced volume of the flame tube and a two-zone combustion chamber, as well as a combustion chamber with preliminary preparation of the fuel-air mixture in the burner device are considered.

The features of burner devices of these combustion chambers are considered. For a serial combustion chamber, the burner device contains a nozzle, a swirler and a diffuser nozzle attachment. For a shortened combustion chamber, a confuser nozzle attachment is used. A two-zone combustion chamber contains two types of burner devices: diffusion for the duty zone and with preliminary mixing for the main zone. The combustion chamber with preliminary preparation of the fuel-air mixture contains a dual-circuit burner device with hollow blades and a central nozzle, which allows for regulation of fuel consumption along the circuits to ensure the required level of toxic emissions in the corresponding engine operating modes.

The paper also provides a description of the bench equipment for purging burner devices, on which tests were conducted to determine their flow characteristics. The parameter of throughput, which is determined for each burner device, is derived.

A description is given of the test bench equipment for purging combustion chambers, on which tests were carried out to determine pressure losses on the walls of combustion chamber fire tubes and total pressure losses in the combustion chamber under various inlet conditions for air velocity.

A calculation and experimental method for determining the excess air coefficient at the outlet of the burner devices is presented. It is determined that in the combustion chambers under consideration, there is a tendency for the fuel-air mixture to become leaner at the outlet of the burner device. This ensures a reduction in nitrogen oxide emissions. Regulation of fuel consumption in the corresponding combustion chamber zones allows for an optimal level of emissions in various engine operating modes.

Venus is the second planet from the Sun and the closest to Earth. Its atmosphere is the densest, and the temperature on the surface of Venus is the highest of all the planets in the Solar System. Due to convection and thermal inertia of the dense atmosphere, the temperature on Venus does not change significantly between the day and night sides of the planet. The temperature of the upper layers of the atmosphere is about –45 °C. The minimum surface temperature is at least 400 °C. The pressure on the surface of the planet is 90 times higher than at the surface of the Earth. Due to the complexity of the functioning of spacecraft (SC) on the surface, the planet remains virtually unexplored.

However, at an altitude of just over 50 km there is the tropopause – the boundary between the troposphere and the mesosphere. Here, the conditions are most similar to the conditions on the surface of the Earth. This is the optimal area for SC, where the temperature and pressure will be similar to those on Earth.

It is most advisable to send balloon probes to this area to collect scientific information. The aim of the study is to develop a design for an aerostat probe that will provide long-term transmission of information from the tropopause of the Venusian atmosphere. The work includes a ballistic calculation of the descent trajectory of the spacecraft in the Venusian atmosphere and the trajectory characteristics. To determine the parameters of the descent trajectory, a program was written to calculate the differential equations of motion of the atmospheric probe. The work includes a design for an atmospheric probe and the order of its operation.

The activity urgency is connected with requirement of heavy spacecraft ascent into high working orbits. The solar thermal propulsion (STP) with double-stage latent heat thermal energy storage (TES) is intended for space vehicle delivery into geostationary orbit (GEO). Double-stage TES contains peripheral stage as “solar concentrator – sunlight absorber-thermal energy storage” system (CATS) with relatively low-temperature heat-accumulating phase-changing material (HAM) having high latent heat of fusion, for instance, lithium hydride, and high-temperature central stage with high power-intensive TES, for example, beryllium oxide, that allows obtaining of high specific impulse 900 sec. Inter-orbital transfer time from low earth orbit (LEO)-to-GEO varies from 20 to 90 days. Expedient optical-energetic characteristic parameters of the STP for each flight time shows that expedient accuracy of the solar mirror concentrator is much less in comparison with single-stage CATS with beryllium oxide as the HAM, therefore the CATS Sun tracking conditions can be significantly simplified. Comparison between the STP and alternative means of inter-orbital transportation shows that payload mass on GEO seriously exceeds that for liquid propulsion or combined upper stages with both chemical and electric propulsion. Use of the STP with heated hydrogen after-burning allows payload mass increasing at relatively low transfer time, as well as reduction of space vehicle dimensions and the CATS complication. The expedient oxidizer-to-fuel mass ratios depend on LEO-to-GEO trip time. The considered possible variants of payloads – geostationary communication satellites – can be injected into the target orbit with use of “Soyuz-2.1b” middle class launchers having the “solar” upper stage instead of “Proton-M” heavy rockets class with chemical liquid-propellant kick-stages.

The relevance of the work is explained by the significant problems of the modern aerospace industry, mechanical engineering, energy, mining, processing and other industries in the disposal of waste products made of composite materials and products based on composites of various functional purposes (carbon fiber, fiberglass, metal-ceramic and cast glass reinforced).

The aim of the work is to increase the efficiency of processes for obtaining micron fractions of composite materials waste through the use of an upgraded roller crusher-shredder design.

Computational and experimental studies have substantiated the possibility of increasing the efficiency of waste recycling of composite materials due to their gradual (step-by-step) disintegration. Based on analytical calculations and finite element analysis methods, a kinematic scheme, layout and design of an upgraded prefabricated roller crusher-shredder with working bodies (discs) in the form of an equiaxed contour – a Relo triangle – have been developed. The new design implements a more complex system of forces (compression, friction, alternating cyclic loads) compared to analogues, which makes it possible to increase the speed and productivity of the crushing process. The process of cutting the material using the “rotating scissors” mechanism is implemented between adjacent counter knives of the PK profile, which also contributes to more intensive grinding of the material (especially when processing lamellar or long fragments of waste). The original location and inconsistency of the contact points of the oncoming profiles, the gap between the discs during their rotation creates a rolling effect due to the reciprocating movement of the crushed material, which reduces the risk of jamming and increases the throughput of the grinding rolls and the intensity of the disintegration processes. In order to determine the best performance in terms of the size of the working bodies of the crusher, the gap between them when grinding materials with different sizes and properties, kinematic models were created to simulate the grinding processes and conduct a numerical experiment using finite element analysis methods. It is shown that due to the effective combination of various fracture mechanisms (abrasion, crushing, cutting, alternating loads), the intensity of deformation processes and specific loads on the material increases, but the stresses on the working surfaces of the crusher vary in the range of 430–580 MPa, the safety margin of the working bodies increases to 0.43–0.65, which is a prerequisite for increasing the service life of the workers. grinding elements. The results of calculations using new methods and kinematic schemes show that the design of the upgraded prefabricated roller crusher with working bodies in the form of a Relo triangle has an increased resultant speed (by 30 %) and productivity is almost 2 times higher than the prototype with cylindrical rolls (with the same or comparable sizes of working bodies, kinematic parameters in terms of rotation speed and drive power). Design and technological preparation was carried out and a prototype of the installation for experimental studies was made, which confirmed a good agreement between the calculated and experimental data on the size of the gap, the speed and productivity of the crushing and crushing process.