Vol 23, No 4 (2024)

The article proposes a method for optimizing the layout of on-board equipment in spacecraft compartments according to the criterion of the minimum mass of the on-board cable system. The purpose of the work is to create a unified methodology for placing devices and verifying compliance with technical requirements. Methodological calculations are presented regarding the accounting of connections between devices and with other elements of systems, as well as a preliminary estimate of the mass of the on-board cable system, as a problem of variational calculus with elements of topological optimization. An algorithm for placing devices is based on their connection diagram with the ability to control the implementation of ergonomic, installation, size, mass centering requirements for the layout. Testing was carried out using the example of a spacecraft with a cylindrical compartment. It was organized in several stages in order to trace the change in the mass of the on-board cable system when the devices were displaced to meet the ergonomic, installation, and size requirements. The results of the tests made it possible to improve the procedure for determining the coordinates of instrument arrangement and the values of overall clearances. They also made it possible to compare the resulting mass of cables with statistics. The proposed methodology continues to be used in experimental testing by design engineers; some of its provisions will be developed in further research.

An example of practical application of the methodology of multidisciplinary optimization of the concept parameters of aircraft-type flight vehicles is considered in the form of solving the problem of modifying two existing aircraft with characteristics presented in open sources. The convergence of the optimization problem was investigated. The results of validation of mathematical models of aerodynamics are presented by comparison with the experiment results. An assessment of the reliability of the calculation of the objective function was carried out using the example of solving the direct problem of calculating the take-off weight and flight performance characteristics of prototype aircraft and comparing the results with their real characteristics. A method for longitudinal trim of aircraft-type flight vehicles with two lifting surfaces with parameter optimization is proposed.

The purpose of the work is to develop and describe a new method of testing spacecraft electronic equipment. The article substantiates the relevance of developing new methods and means of testing on-board electronic equipment of spacecraft based on the intentional introduction of faults for the purpose of testing survivability algorithms. It was shown that carrying out such tests makes it possible to increase the completeness of control and reliability of on-board electronic equipment of spacecraft while simultaneously reducing testing costs. A new method for testing spacecraft software based on fault injection is proposed, which is used to solve the specific task of checking orientation and stabilization modes. The proposed method makes it possible to develop semi-natural models of on-board electronic equipment of increased adequacy and reconfigurability due to the use of programmable logic integrated circuits as the basis of hardware and software complexes. The proposed method is implemented on the hardware and software of a ground-based debugging complex for on-board electronic equipment and is distinguished by the ability to simulate a wide range of on-board electronic equipment, low cost and mobility. All technical solutions described in the article were introduced into the production process when creating modern spacecraft for communications, radio navigation and geodesy.

This paper presents a model for analyzing the interaction of laser radiation and a metal-powder composition in the process of direct laser growing of large-sized combustion chambers of gas turbine engines. The metal-powder composition is fed into the melting zone coaxially with laser radiation; the task is to completely melt the powder with laser radiation before it enters the melt bath on the construction platform. The laser radiation is absorbed as it passes through the gas-powder jet, and its energy is also used to melt the construction platform or the previous layer. Thus, in order to determine the parameters of the operating conditions that provide the possibility of melting powder particles, it is necessary to determine the boundaries of the parameters at which each particle of the metal-powder composition completely melts in a gas-powder jet. To simulate heat transfer inside a particle, the
Beer – Lambert laser radiation absorption law was used using the lumped parameter approach. The required energy for melting the powder material was determined through enthalpy. The resulting one-dimensional differential equation of enthalpy increment is solved numerically by the Euler method. Using this model, the distance from the point of origin of the interaction of the laser beam with a metal-powder composition to the zone of its complete melting was determined and the effect of the velocity of the gas-powder jet, the power of laser radiation, the bulk density of the metal-powder composition and the average radius of the powder particles on the distance to the zone of complete melting was studied.

One of the ways to increase the efficiency of a rocket engine chamber is to ensure the fixed nozzle operation in the design mode over the entire range of altitudes (ambient pressure) of engine operation. The paper presents the results of a full-scale experiment of the annular nozzle model with a flat central body. The purpose of the experiment was to evaluate the efficiency in terms of the specific impulse of the annular nozzle with a flat central body in comparison with the Laval nozzle. The tests were carried out at the “hot” bench of the Department “Engines and Power Plants of Aircraft” BSTU “VOENMEH” named after D.F. Ustinov. The generated high-temperature steam-gas was used as a working fluid, the experiment was carried out under terrestrial conditions. During the stand testing the readings of operating parameters (pressure, mass flow, thrust, components ratio) were recorded in automated mode. The parameters were changed by reconfiguring the appropriate elements of the pneumohydraulic system. Based on the processed results of the tests the efficiency of the annular nozzle with a flat central body was evaluated in comparison with the Laval nozzle, and the values of the experimental data were verified with the theoretically expected ones.

A generalized-structure analytical model of a pressure pulsation damper for pipeline systems is presented. The model was obtained using the four-pole method. The model is obtained in lumped and distributed parameters. The distributed-element model and finite element model are used for calculating the inherent characteristics of the pressure pulsation damper. The analytical distributed-element model takes into account the distribution parameters of the central inertial channel by introducing into the analytical model a matrix for the distributed element instead of the matrix of inertial resistance. A finite element parametric model of a two-stage reactive-type oscillation damper is developed in the Ansys software. Pulsation processes in the damper are modeled using acoustic analysis. The frequency-dependent coefficients of the damper transfer matrix are calculated for three models using three numerical experiments with a section of the pipeline system with the dynamic characteristics known in advance. The characteristic parameters of the pressure pulsation damper are calculated. These are the wave input impedance, wave output impedance and the inherent vibration damping. The calculation was carried out using analytical and finite element models. A single-stage reactive pressure pulsation damper is developed. The damper is designed in such a way that its settings such as the resistance of the jets and resonance tubes, the length of the central channel and the capacity of the expansion cavity can be changed. The results of experimental and numerical research of the inherent characteristics of a single-stage reactive of a vibration damper are presented.

The paper presents the results of simulation of spray and combustion processes in the liquid-propellant rocket engine chamber using the z77 reduced kinetic mechanism of chemical reactions and a hybrid method for determining spray parameters of a swirl atomizer. Simulation was carried out for the nominal operational conditions in a three-dimensional domain using the ANSYS Fluent software. The process of spraing liquid fuel components (T-1 kerosene and oxygen) by monopropellant injectors was simulated using a model of discontinuous phases. The simulation results (pressure, temperature and velocity) were compared with the data of analytical thermogasdynamic calculation results and experimental results for pressure in chamber and gas temperature near the wall. The difference between the simulation results and the experimental results does not exceed 8%. Thus, it was shown that it is possible to use the mechanism z77 and hybrid method for determining spray parameters of a swirl atomizer presented in this paper to obtain accurate simulation results of the kerosene T-1 and oxygen spray and combustion processes of the investigated liquid-propellant rocket engine.

A pressure sensor with a piezoelectric sensing element was developed for the information and measurement system of the technical condition of a rocket engine. The main technical characteristics of piezoelectric elements of laboratory specimens were obtained theoretically and experimentally. To analyze the microstructure of the piezoelectric element material, slices were made, and when analyzing photos of the cuts, it was found that the piezoelectric material has dense structure and the pores are small, evenly distributed over the volume. A laboratory model of technological equipment for plasma modification of charge based on lead and lead-free components was developed and tested.