Annotation: Specialized design office for liquid engines was established on July 22, 1958 to develop engines and propulsion systems, powered by liquid propellants to be installed on the combat missile systems and integrated launch vehicles (LV), developed by Yuzhnoye SDO. Moreover, liquid engines design office was assigned with manufacturing and testing of the main rocket engines, developed by NPO Energomash and to be installed on Yuzhnoye-developed launch vehicles. Over the past 66 years Yuzhnoye SDO has developed more than 40 liquid rocket engines (LRE) of various purpose, designed both to gas-generator cycle and to staged combustion cycle. Seventeen of them were commercially produced by Yuzhmash PA and installed on launch vehicles. Nowadays Yuzhnoye propulsion experts keep working on development of the advanced liquid rocket engines powered both by cryogenic and hypergolic propellants, which satisfy the majority of launch service market demands. Within the framework of extensive cooperation with foreign space companies, on a contract basis, Yuzhnoye propulsion experts are working on the design and development testing of the liquid rocket engines, as well as their components. The accumulated vast experience in the development of liquid rocket engines nowadays enables high scientific and technical level in the creation of up-to-date engines, demanded in the world market. Significant steps in this area have been made by the experts from the Yuzhnoye propulsion division and then subsequent manufacture and delivery by Yuzhmash PA of the engine intended for the European rocket Vega Stage 4; and designing the individual components for the engines with thrusts ranging from 500 kgf to 200 tf ordered by foreign customers. This article provides the review of current and scheduled activities of the Yuzhnoye SDO to develop the liquid rocket engines within the thrust ranges from ~ 40 kgf to ~ 500 tf.

Annotation: Launch vehicle lift-off is one of the most critical phases of the whole mission requiring special technical solutions to ensure trouble-free and reliable launch. A source of increased risk is the intense thermal and pressure impact of rocket propulsion jet on launch complex elements and on rocket itself. The most accurate parameters of this impact can be obtained during bench tests, which are necessary to confirm the operability of the structure, as well as to clarify the parameters and configuration of the equipment and systems of complex. However, full-scale testing is expensive and significantly increases the development time of the complex. Therefore, a numerical simulation of processes is quite helpful in the design of launch complexes. The presented work contains simulation of liquid rocket engine combustion products jet flowing into the gas duct at the rocket lift-off, taking into account the following input data: the parameters of propulsion system, geometric parameters of launch complex elements, propulsion systems nozzles and gas duct. A three-dimensional geometric model of the launch complex, including rocket and gasduct, was constructed. The thermodynamic parameters of gas in the engine nozzle were verified using NASA CEA code and ANSYS Fluent. When simulating a multicomponent jet, the equations of conservation of mass, energy, and motion were solved taking into account chemical kinetics. The three-dimensional problem was solved in ANSYS Fluent in steady-state approach, using Pressure-based solver and RANS k-omega SST turbulence model. The calculation results are the gas-dynamic and thermodynamic parameters of jets, as well as distribution of gas-dynamic parameters at nozzle exit, in flow and in boundary layer at gas duct surface. The methodology applied in this work makes it possible to qualitatively evaluate the gas-dynamic effect of combustion products jets on gas duct for subsequent optimization of its design.

Annotation: The article considers the present-day aspects of predicting and establishing the guaranteed service life of liquid rocket engines. The phases and sequence of works to specify the guarantee periods are presented. The physical ground for determining thermal ageing test modes and increased humidity test modes is set forth. The mathematical dependencies are given to determine the time of testing at increased temperature, increased relative humidity, equivalent article storage temperature. The generalized list and sequence of tests to establish a guarantee period are set forth. The content of works is considered to seek for and introduce new components of inter-industry application, in particular, replacing materials for rubber mixtures during production of rubber technical goods, polymer materials (fluoroplastics, polyamides), isotropic pyrographite, ozone friendly means for degreasing liquid rocket engine assemblies being in contact with propellant component – oxygen and to seek for alternative bearings.

Annotation: At Yuzhnoye State Design Office, the Cyclone-4 launch vehicle 3rd stage engine has been developed and is under testing. For adjustment of the engine and test bench systems, in the first firing tests the radiation-cooled nozzle extension was replaced with a steel water-cooled one. It was planned to start the engine with water-cooled nozzle extension without vacuumizing and without gad dynamic pipe, which conditioned operation with flow separation at the output edge of water-cooled nozzle extension. Therefore, the calculation of flow in the nozzle with water-cooled extension, flow separation place, and thermal load on watercooled nozzle extension during operation in ground conditions is an important task. Selection of turbulent flow model has a noticeable impact on prediction of flow characteristics. The gas dynamic analysis of the nozzle with water-cooled extension showed the importance of using the turbulent flow model k-ω SST for the flows with internal separation of boundary layer and with flow separation at nozzle section. The use the flow model k-ω SST for calculation of nozzle with flow separation or with internal transitional layer allows adequately describing the flow pattern, though, as the comparison with experimental data showed, this model predicts later flow separation from the wall than that obtained in the tests. The calculation allows obtaining a temperature profile of the wall and providing the recommendations for selection of pressure measurement place in the nozzle extension for the purpose of reducing sensors indication error. With consideration for the special nature of the nozzle extension wall temperature field, the cooling mode was selected. The tests of RD861K engine nozzle with water-cooled extension allow speaking about its successful use as a required element for testing engine start and operation in ground conditions without additional test bench equipment.

Annotation: In the present-day rocket engineering, the liquid rocket engines with pump feed system have gained wide acceptance. As a rule, the pumps used in liquid rocket engines are screw-axifugal. The screw serves to increase pressure upstream of the axifugal wheel, thus ensuring its cavitation-free operation. The screws used in the screw-axifugal pumps of liquid rocket engines may be of two types: with constant and variable step. The screws with constant step are easier to calculate, profile and manufacture as compared to the screws with variable step. As known from the literature, the use of the screw with variable step increases power characteristics of the screw-axifugal pump. The purpose of investigation is comparative analysis of cavitation and power characteristics of the following high-speed low-consumption screw-axifugal pumps of liquid rocket engines with jointed screws, screws of constant and variable step:  RD868 engine oxidizer and fuel pumps;  RD859 engine fuel pumps;  RD861K engine fuel pumps. Besides, the analysis has been made of the impact of design features and geometrical dimensions of the screws with variable and constant step on power characteristics of the screw-axifugal high-speed lowconsumption pumps of liquid rocket engines. Special attention has been given to the analysis of anticavitation properties of the pumps with screws of variable step and pumps with jointed screws. Based on the results of investigation, it has been ascertained that when using the joint screws and screws with variable step instead of the screws with constant step in the high-speed low-consumption screw-axifugal pumps of liquid rocket engines, the pump delivery head increases from 0.65 to 3.83%, the efficiency increases up to 1.7%. The use of jointed screw and screw of variable step as compared with the screw of constant step does not have any impact on cavitation properties of low-consumption crew-axifugal pumps of liquid rocket engines.

Annotation: The article describes the problems of manufacturing large-size nozzle blocks by classical for Ukrainian space industry method of high-temperature brazing. The Yuzhnoye SDO-selected way of solving this problem and the first strides on the way to organization of new production using innovative technologies of laser welding and surfacing are presented. The step-by-step sequence and procedure of research work to develop and test a new technology of cooled nozzle block manufacturing are described. Four phases are identified, out of which the first two phases have already been successfully performed. The laser welding and surfacing technology will allow avoiding the use of costly and unique equipment and will allow reducing and optimizing the technological manufacturing cycle rejecting the long –term and energy-consuming technological operations. The scientific-and-technological works performed showed the principle feasibility of making connection between the external jacket and internal wall of a nozzle block using laser welding. The test samples manufactured confirmed the high strength characteristics, which had been preliminary obtained by the theoretical calculation methods. The sections obtained by surfacing demonstrate good metallurgical connection between the layers. On the test samples, the technique was tried-out allowing repairing defect areas in a welded seam obtained by laser welding method. This is especially important from the technological and economic viewpoints, as the technology of high-temperature brazing applied currently does not allow making guaranteed repair of brazed joints.

Annotation: During experimental investigation of the dynamic characteristics of a pneumatic test bench for testing liquid rocket engine high-flowrate automatic units, the effect was detected of 20-35% sound speed increase in the gas flow moving along the channel with corrugated wall (metal hose) which is a part of test bench drain system. The article presents the results of experiments and the task of theoretical justification of the effect is solved. It is indicated that its causes may be two mutually complementary factors – a decrease of gas compressibility at eddy motion and oscillations of metal hose wall. The physical model is considered that describes variation of gas elasticity and density in the conditions of high flow vorticity. It is supposed that in the near-wall layer of the channel, toroidal vortexes (vortex rings) are formed, which move into turbulent core of the flow where their size decreases and the velocity of rotation around the ring axis of torus increases. The spiral shape of the corrugation ensures also axial rotation, which increases vortexes stability. The intensive rotation around the ring axis creates considerable centrifugal forces; as a result, the dependence of pressure on gas density and the sound speed increase. The mathematical model has been developed that describes coupled longitudinal-lateral oscillations of gas and channel’s corrugated shell. It is indicated that in the investigated system, two mutually influencing wave types are present – longitudinal, which mainly transfer gas pressure pulses along the channel and lateral ones, which transfer the shell radial deformation pulses. As a result of modeling, it has been ascertained that because of the lateral oscillations of the wall, the propagation rate of gas pressure longitudinal waves (having the same wave length as in the experiments at test bench) turns out to be higher than adiabatic sound speed.

Annotation: The article presents the experience of the first liquid rocket engine parts developing and manufacturing by means of additive technologies. Application of these technologies imposes new constraints on parts configuration, which are necessary to be considered by a designer. At the same time, application of additive technologies provides new opportunities to a developer, which are absent at traditional method of manufacturing. The article presents the results of manufacturing in Yuzhnoye SDO the first commodity parts, manufactured by additive technologies – selective laser melting, using SLM280HL 3D- printer with building volume dimensions of 280x280x350 mm. The obtained experience in the first liquid rocket engine parts developing and manufacturing by means of additive technologies has shown, that application of this technology allows manufacturing the parts having high characteristics at minimum terms and cost of preproduction, however for all potential opportunities realization, especially at implementation phase, it is necessary to change designing philosophy, which will require more working hours at designing. The obtained first results conclusively prove efficiency and expediency of additive technologies application at certain segment of liquid rocket engine parts manufacturing, at that it is clear, that manufacturing equipment improvement and design methods evolution will lead to steady expansion of this segment.

Annotation: In the pneumohydraulic systems of liquid rocket engines and propulsion systems, electromagnetic valves that allow making the pneumohydraulic systems more simple and ensuring multiple ignition of liquid rocket engines have found wide application. The Yuzhnoye-developed electromagnetic valves are designed according to two schemes – of direct and indirect action. In the direct-action electromagnetic valves, the shutting-off device opens (closes) the throat with the force developed by electric magnet. They have gained acceptance in the pneumohydraulic systems with the working medium pressure of ~8.5 MPa, they are of simple design and have high operating speed (0.001…0.05 s). In the electromagnetic valves with amplification, the electromagnet armature is connected with control valve and the main shutting-off device moves due to the force from working medium pressure drop on it. They are used in the operating pressure range of 0.5…56 MPa, at that, the action time is 0.025…0.15 s. For the European Vega launch vehicle fourth stage main engine assembly that has pressure propellant feeding system, the electrohydraulic valve with amplification and drainage was developed. The dependence of this electrohydraulic valve high speed from the line’s output length is decreased to the maximum due to the installation of Venturi nozzle at the output connecting branch. This electrohydraulic valve is operable at the pressure below 8 MPa, the action time is 0.08…0.12 s. The present-day spacecraft gas-jet orientation and stabilization systems use as propulsion devices the electromagnetic valves with nozzles whose thrust is, as a rule, not more than 30 N and the working medium pressure is up to 24 MPa. Yuzhnoye State Design Office developed for 15B36 gas-jet system the electropneumatic valve with amplification and nozzle, which is operable at the pressure below 45 MPa, ensures the action frequency of up to 10 Hz and is capable of creating the thrust of 100 N on gaseous argon. To solve the task of decreasing the dependence of operability and high speed of electromagnetic valves with drainage and amplification on geometry of lines in which a valve is installed, the electropneumatic valve was developed that has spool elements ensuring reliable and quick action with long input lines of 0.004 m diameter. Its mass is 2…2.5 times lower than the mass of analogs. Recently, Yuzhnoye State Design Office develops the apogee RD840 LRE with 400 N thrust, for the conditions of which the direct-action electrohydraulic valve was developed and tested with the following characteristics: pressure – up to 2.15 MPa, consumed power in operation mode – less than 7.1 W, action time – not more than 0.02 s, mass – 0.19 kg. The presented electromagnetic valves by their technical and operational characteristics meet the highest world requirements and have found wide utility in liquid rocket engines and propulsion systems.

Annotation: The article presents the experience of creating LRE turbopump units by the Rocket Engines Design Office (DO-4) at Yuzhnoye SDO. The best known turbopump units designs developed by DO are described. Both earlier developments of DO and the turbopump unit being now in final testing phase are considered. The design evolution of both separate assemblies and of entire unit is shown. The design evolution allowed increasing the unit’s lifetime dozens times. For example, the lifetime of the first turbopump units developed by DO did not exceed 150 s. Currently, the DO has in stock the engines with lifetime of ~19000 s. The information is presented on the problems that the designers faced in testing the turbopumop unit and the ways to solve them. The unique achievement are presented. At present, there are no analogs of some units in the world. The article presents the information on the latest achievements of DO, such as the face seal on pump vane discs whose use fully excludes unwanted leaks. Having analyzed the data presented, one may conclude that the Rocket Engines Design Office and Yuzhnoye SDO as a whole accumulated sufficient experience and knowledge allowing solving any problems that may arise when developing a new LRE turbopump unit, and successfully operating LRE with turbopump units, including those in the engines with generator gas afterburning created in recent years testify to a great value of accumulated experience.