Annotation: The pyrobolts, or explosive bolts, belong to the pyrotechnical devices with monolithic case consisting o f the cap, as a rule with hexagonal surface, and of cylindrical part with thread. The pyrobolts are separated into parts using the pyrotechnical charge placed inside the case. Owing to the simple design, reliability and short action time, the pyrobolts have found wide application in aerospace engineering for separation of assemblies and bays, in particular, stages, head modules, launching boosters, etc. So, for example, about 400 pyrobolts are used in the Proton launch vehicle. The designs of pyrobolts are markedly different. By method of explosive substance action on case structural elements, the pyrobolts are divided into two types: the pyrobolts using the shock wave formed at detonation of brisant explosive substance for case wall destruction and the pyrobolts using the pressure of gases arising at pyrotechnical charge blasting. By method of separation into parts, they are divided into fragmenting pyrobolts with ridge-cut, with piston, and shear pyrobolts. The paper deals with the design of various types of pyrobolts, their disadvantages are considered. The Yuzhnoye SDO-developed pyrobolt of shear type with segments is presented that uses radial shear forces of segments located in the hole of cylindrical part to separate the case parts. The above segments a re actuated using a rod with sealing rings and a piston connected to the rod through a rubber gasket; the piston moves under pressure of gases formed during pyro cartridge action. The following calculations are presen ted: strength analyses with determination of case load-carrying capacity; power analyses with justification of pyro cartridge selection for pyrobolt actuation. In the developed pyrobolt of shear type with segments, the case parts are separated without considerable shock loads and without high-temperature gases and fragments release into environment, ensuring reliable separation of bays and assemblies without damaging sensitive equipment.

Annotation: The main solid rocket motors of surface-to-air missiles and some short-range missiles have, as a rule, two operation modes – starting (augmented rating) and cruise (with decreased propellant consumption level). The methods to calculate intraballistic characteristics of such motors have a number of peculiarities, which set them apart from the methods of determining the characteristics of motors with constant propellant consumption level. The purpose of this article is to analyze such peculiarities, design methods, to find interrelation between the parameters of propellant consumption diagram, to determine the impact on the latter of motor design features and propellant characteristics. To achieve this goal, the method of analytical dependencies was developed. The equations obtained show that the required parameters of diagrams (including consumption-thrust characteristics difference between the starting and cruise modes) can be ensured due to varying either case diameter or propellant combustion rate or due to combined variation of these values. In practice, the cases are possible when for some reasons it does not seem possible to vary the case diameter or propellant combustion rate and the requirements to consumption diagram cannot be satisfied to the full extent. The task of motor developer in that case consists in determination of acceptable (alternative) propellant consumption diagrams that would be closest to required. The proposed method is based on calculation and construction of nomograms of dependencies of relative propellant consumption in cruse mode on relative time of starting leg at different propellant combustion rates and constant (required) case diameter and vice versa, at different values of case diameter and constant (available) propellant combustion rate. Using these nomograms, the rocket developer can determine the propellant consumption diagram acceptable for the rocket. In a number of cases, design limitations for separate main motor assemblies are imposed on consumption characteristic diagram that have an impact on its required parameters. The presented materials allow evaluating that impact and contain the proposals to remove it. The presented method allows quickly determining the conditions needed to fulfill required propellant combustion products consumption diagrams and in case of nonfulfillment of these conditions – allow presenting alternative options for selection of most acceptable one.

Annotation: The structure examined herein aims to keep fuel from entering the space behind the cuff, evacuate the space behind the cuff, reliably fasten the cuff to the thermal protective coating of the bottom in the process of charge forming, easily release the cuff after charge forming, and remove the support structure elements from the casing after charge polymerization when equipping. The structure was tested in the process of fueling the solid rocket motor casing and during charge polymerization. In order to comply with the specified requirements the cuff functions were identified, the structures previously developed were analyzed, and a new structure was designed and improved after testing. The improved structure ensured that fuel did not enter the space behind the cuff; it was removed easily after charge forming. Conclusions proved the suitability of this stricture.

Annotation: The results of tests of high-voltage measuring current transformers TFRM with discharge valves and reinforced porcelain cover, in which transformer oil is used as internal insulation, by means of explosive blasting simulating short circuit inside current transformer, are under consideration.

Annotation: The paper considers possible ways of the development of impulse SRM with operating time from 0.02 to 0.05 s. The tests of prototype motor show the development capability of such motor. It is suggested to use the existing gunpowders as a charge for impulse SRM.

Annotation: One of the main design parameters of the automatic equipment in the launch vehicle’s pneumohydraulic systems is the flow friction characteristic, which represents the proportionality factor between the automatic equipment pressure differential and velocity head. The flow friction characteristic of the completely open automatic device should have very small value with required dimensions and mass. With decrease of the pressure losses, the required upstream pressure of the propulsion system is ensured with smaller pressurization of the tanks. It results in the decrease of the required pressurization gas volume, which boosts reduction of the performance of the launch vehicle as a whole. This paper describes the method of reduction of the flow friction characteristic of the dividing valve, optimizing the geometric shape of the flow passage. The problem of minimization of the valve’s flow friction characteristic is considered with the specified mass and design dimensions restrictions. The initial design of the valve was developed, taking into account the specified requirements, literature references and parameters of the analogue units. With the goal of optimization various options of valve design were considered, different from the initial design in configuration of the inlet and discharge nozzles, notably various angle sizes, forming the stream profile, and lengths of the direct-flow sections. Four options of the valve design were calculated using numerical methods of ANSYS CFX software. Navier – Stokes equations and k-ω SST turbulence model were used. Based on the calculations results the optimal design was selected. Initial design of the valve was compared with the optimal one. The flow friction characteristic of the optimal valve design decreased by 26 % in comparison with initial design with insignificant change of mass and dimensions. The design of the developed dividing valve can be involved in the design of the new launch vehicles.

Annotation: Service life (resource) of the device (system, structure, material) is one of the major factors, which defines the reliable performance of the device or necessity of its replacement. The purpose of this paper is to develop the engineering methodology to estimate the service life of the device to support the well-founded design decision-making. The methodology of estimation of the service life of material or structure is based on the generalization of great amount of Yuzhnoye SDO experimental data and theoretical research on the impact of various factors (properties of materials, loads, storage and operation conditions) on their service life on the ground of strength analysis. At the same time, service life definition is based on the results of stress and deformation analyses and their comparison with strength properties of the applied material (tensile strength and deformation properties). Strength properties of the material should be reduced to test conditions in terms of temperature, pressure, rate of loading, degrees of material aging etc. Methodology provides the estimation of safety margins in all phases of storage and operation of the device, consideration of the impact of the active factors (mass, temperature, loading, process of material aging), performance of calculations for the chosen specific zones of the device. It is shown that the service life estimation is in general case a probabilistic observation because of the random combination of the influencing factors (strength properties, storage and operation conditions, loads). Analysis of experimental and computation data as applied to solid-propellant rocket engine shows that the most dangerous zones, which define the service life, are the fuel charge channel (deformations at launch), a fuel-body coupling zone (breakaway coupling stress) and a “lock” zone of the release collar (concentration of shear and breakaway stresses and deformations). Developed methodological guidelines of the engineering estimate of the service life can be used as the computational basis for the service life of materials and structures in the phase of system design and updating of the assumed design solutions.

Annotation: By way of example of small-size motor with one-grain charge, the possibilities are shown that open up for a designer when selecting the optimal configuration of diaphragm using the Ansys (CFX) software package. The calculation results are compared with the experimental data obtained during hot-fire bench tests of experimental SRM.

Annotation: A comparative assessment of effectiveness of usage of hybrid rocket motors and solid rocket motors for meteorological rocket with propellant mass of 540 kg is made. Different combinations of oxidizer and fuel are considered based on which the power characteristics of hybrid rocket motors were determined. Based on the results of investigation, an assessment is given of ballistic effectiveness of hybrid rocket motors, the peculiarities of combustion process and of selection and designing of solid propellant charge shape are analyzed.

Annotation: The factors are considered that have an impact on the value and behavior of SRM flow rate and thrust characteristics after stage separation (in the leg of deep decay). It is shown that thrust behavior in the leg of deep decay is determined by two main processes: afterburning of solid propellant charge residues within the first 3-5 s and mass input of internal thermal protection coating destruction products within the following several tenths of second. The dependences are proposed for design evaluation of SRM intra-ballistic and flow rate/thrust characteristics.