Annotation: The exploratory and experimental investigations were conducted into design of propellant tank made of composite polymer materials for work in cryogenic environment at operating pressure of 7.5 kgf/cm2 . When determining the configuration of a liner-free composite propellant tank, the main requirement was ensuring its leak-tightness at internal excess pressure and cryogenic temperature effect. The world experience of creating similar designs was analyzed and the requirements were defined imposed on configuration of propellant tank load-bearing shells. Before defining the final configuration, the types of materials, reinforcing patterns, and possible ways to ensure leak-tightness were analyzed, and preliminary tests were conducted of physical and mechanical characteristics of thin-wall samples of composite materials and tubular structures with different reinforcing patterns. The tests of carbon plastic samples were conducted at different curing modes to determine the most effective one from the viewpoint of strength characteristics and the tests for permeability by method of mouthpiece were conducted. The tests of pilot propellant tank showed that the calculated values of deformations and displacements differ from the experimental values by no more than 10 %. Using the parameters measurement results from the tests on liquid nitrogen, the empirical formulas were obtained to calculate linear thermal expansion coefficient of the package of materials of load -bearing shell. The empirical dependences were constructed of relative ring deformations at load-bearing shell middle section on pressure and temperature. The tests confirmed correctness of adopted solutions to ensure strength and leak-tightness of propellant tank load-bearing shell at combined effect on internal excess pressure and cryogenic temperature, particularly at cyclic loading. The materials used and propellant tank manufacturing technologies ensure leak-tightness of load-bearing shell at liquid nitrogen operating pressure of 7.5 kgf/cm2 and strength at excess pressure of 15 kgf/cm2 and allow conducting approbation of prospective stage of the integrated launch vehicle.

Annotation: The paper presents the variation of parameters of gas-vapor mixture of hypergolic rocket propellant components in a filling tank in the process of rocket propellant components filling into it with “closed drainage” depending on tank filing coefficient and initial parameters of environment in the tank.

Annotation: The paper considers the method of calculation of generative pressurization system for a tank with nitrogen tetroxide in which an attempt is made to model the temperature stratification of gas in the tank throughout the height of the tank. The applied physical model takes into account the impact of gas dynamic processes, heat-mass-exchange, and chemical reactions on gas parameters in the tank. The satisfactory convergence of the calculation results with the experimental data is shown.

Annotation: Long-term experience in development, development testing and use of generating systems of fuel tanks pressurization for rockets powered by nitrogen tetroxide and unsymmetrical dimethylhydrazine is summarized. Replacement of gas bottle pressurization systems with generating ones on such launch vehicles as 15A14, 15A15, 11K68 (8K67), 15A18M substantially simplified operation, reduced the pneumohydraulic feed system mass at least twice and its cost – by five times. Typical stages of development and introduction of the pressurization generating systems are shown: development of generators, their development testing, study of the composition and parameters of gas. The important steps were the development of methodology for pressurization system parameters calculation, which enabled achievement of the substantial improvements of their characteristics, appearance of the high-performance hightemperature (up to ~ 1000o C) unsymmetrical dimethylhydrazine tank pressurization system, study of the degree of impact of each of the pressurization system parameters on the tank pressure. Accounting of the correlation between the flow rate and the generator gas temperature improved the output performance, as well as simplified and reduced the amount of development testing of the pressurization system. Important role of the gas sprayer design in pressurization system parametric configuration is described, and the advanced versions are shown taking into account g-loads, changes in temperature, pressure and propellant level inside the tank. Significant phase in the development of the generating pressurization system was the effective use of the high-temperature pressurization of the fuel tank with submerged propulsion system. Besides for the first time the effect of mechanical temperature destratification of the propellant in the tanks was observed, which occurs during the propulsion systems shutdown. Due to this effect, the Dnepr LV payload capability enhanced. Successful engineering solutions in the design of the pressurization system were defended by ~80 copyright certificates and patents of invention, ~40 of which were successfully implemented.

Annotation: This article considers the issue of achievement of the specified value of propellants saturation by helium after their delivery from the manufacturers to the launch site. Knowing the fact that propellants gas saturation or gas separation processes are labour-consuming and costly this issue is of immediate interest. In order to solve this problem number of factors have been considered, which determine the value of gas saturation in the propellants delivered to the launch site and procedure to control the value of gas saturation by the fuel manufacturer has been developed. This procedure implies that shipping tank container is pressurized after being fueled with propellants at the manufacturer’s, the pressure is characterized by the value of the known initial deficit or excess of gas in the propellants, following which tank container is delivered to the launch site. During transportation tank container is subjected to various kinds of mechanical actions (vibration, rolling and pitching in the sea, braking, transshipment), therefore intensive mixing of propellants occur. As propellants mix, process of propellant saturation occurs when certain amount of gas transits from tank container’s gas volume into the liquid, therefore certain gas saturation is reached. Article includes the measuring results of the gas liquid medium parameters inside the tank containers with fuel in the process of fuel transportation to Ukraine from PRC factories and estimations of the measuring results using the developed model which confirmed the quantitative nature of the mass exchange processes, included in the model, going on in the gas liquid medium during transportation of the tank container with fuel equipment. It has been determined that due to inevitable errors in the measuring of the specified parameters by the tank container, the achievement of the specified gas saturation with high precision is problematic. In spite of the fact that this procedure does not provide exact value of the specified gas saturation, its application will accelerate and make cheaper the process of fuel preparation for filling operations at the launch site, which is especially relevant in case of fuel saturation by helium. Based on this fuel saturation by helium procedure, the complex technology is suggested, providing controlled gas saturation during fuel delivery and subsequent adjustment of gas saturation using launch site equipment. Therefore, this article develops and studies the original model of the controlled gas saturation of the fuel during its delivery to the consumer. Alternative of the practical use of the study results is suggested in the form of the complex technology of fuel saturation by helium, delivered in the tank containers from the manufacturer to the launch site.

Annotation: When accomplishing the task of spacecraft orbital injection, the necessity arises of main engine multiple ignitions and consequently, long pauses between the ignitions are possible. As the propellant during pauses between ignitions is in the conditions of practically full absence of gravitation and can freely move over entire tank volume taking practically any spatial position, to ensure main engine guaranteed ignition the necessity arises to move the propellant into pre-start position. The propellant is moved to the supply lines by way of creating longitudinal acceleration which is done using inertial continuity ensuring means (thrusters). The time of full liquid displacement from one position into another is the most important parameter having an impact on propellant amount in the tanks and accordingly, on power characteristics of a stage. The theoretical calculations of hydrodynamic processes are connected with considerable mathematical difficulties caused by complexity of solving hydrodynamic problems of determination of liquid flowing with free surface taking into account surface tension of the liquid and many other geometrical, kinematic, and dynamic factors. Therefore, the most reliable data from solving these problems are currently obtained only on model hydrodynamic stands where it is possible to model liquid behavior in tanks in the conditions of variable gravitation. The paper presents the authors-developed procedure of calculating the full time required for propellant components deposition during rocket’s apogee stage flight and the procedure of selecting the modeling parameters (scale, time, and acсeleration) to ensure development testing in the conditions of limited test stand base. The use of the proposed procedure allows (in initial phase of launch vehicle development) determining the full time required to perform deposition with sufficient accuracy and thus optimizing the propellant mass required for operation of inertial continuity ensuring system, which in its turn, will allow increasing the payload mass to be injected.