Use of the Low-Potential Heat for Heating Helium in Rocket-Carrier Tank Pressurisation Systems

The energy efficiency of new technical developments is a critical issue. It should be noted that today the focus in this issue has seen a major shift to the maximum use of renewable energy sources. The purpose of this research is to reduce the weight of helium heat exchangers of the fuel tank pressurisation systems in modern rocket propulsion systems that use fuel components like liquid oxygen and kerosene-type fuel. This is the first time that the question has been raised about the possibility and advisability of increasing the temperature of helium at the heat exchanger inlet without the use of additional resources. The paper addresses the use of the waste (“low-potential”) heat and ”industrial wastes” present in propulsion systems. Basic laws of complex heat exchange and the retrospective review of applicable heat exchanger structures are applied as a research methodology. Two sources of low-potential heat are identified that have been previously used in the rocket engine building in an inconsistent and piecemeal manner to obtain and heat the pressurisation working fluid. These are the rammedair pressurisation during the motion of the rocket carrier in the atmosphere, and the tank pressurisation as a result of boiling of the top layer of oxidiser which is on the saturation line. This is the first time that the advisability has been substantiated of increasing the temperature of the working fluid at the heat exchanger inlet, first of all due to the use of the low-potential heat. This is also the first time that unemployed sources of low-potential heat and “industrial wastes” are found in modern deep throttling propulsion systems. These are the high-boiling-point fuel in the tank, behind the highpressure pump, at the exit of the combustion chamber cooling duct, and also the fuel tank structures, and the engine plume. A possibility is proved, and an advisability demonstrated of their implementation to increase the efficiency of pressurisation system heat exchangers. This is the first time that the methodology of combustion chamber cooling analysis has been proposed to be adopted for the heating of heat exchanger by the engine plume. This is the first time that a classification of waste heat sources has been developed which can be used to increase the pressurisation working fluid temperature. The identified reserves help to increase the efficiency of the helium heat exchangers of the tank pressurisation systems in the propulsion systems

Models for measuring the liquid level in thetank of rocket carrier

The models for measuring the level of a viscous incompressible fluid in the tank by liquid level in the measuring tube are considered. The tank is in the gravitational field and the level of liquid inside varies according to some law. The base model is the first boundary value problem for nonlinear integro-differential equation of parabolic type. The empirical model is Cauchy problem for nonlinear ordinary second order differential equation. It is numerically founded that for linear time-decreasing level of fluid tank fluid level in the measuring tube oscillates about level in the tank with damping amplitude.

PROCEDURE OF CALCULATING THE REDUCED COSTS FOR DESIGNING A COMBINED LOW-ORBIT SATELLITE SYSTEM

The article provides a method for calculating the costs when designing a promising embodiment of a low-bit satellite system. For Ukraine, the prospects for this option lies in the fact that their own means of achieving a large number of satellites in orbit are applied. At the same time, satellites are multifunctional and used to organize communication and broadcasting, the sounding of the atmosphere and the surface of the Earth, subsurface locations, cosmic observation, data collection from the Internet sensors. The space group consists of mini, macro-, nanosterans, which are delivered to the orbit of a domestic rocket carrier into orbit. The technical and economic efficiency of the satellite system lies not only in the above advantages, but also in its hierarchical construction - combination of the root satellite, ministerial repeater, macrovers. The article provides an analysis of other low-bit satellite systems. A feature of the study of the combined LEO is the fact that the proposed construction of the satellite system allows the use of technological distributed registries as one of the through digital technologies. In digital transformation of the economy, the technology of distributed registers plays the same role as Internet things, cloud computing, 5G and Big Data technologies. The method of calculating the presented costs is to calculate the cost of the development, production and operation of the system at the stage of its design. The costs of developing space and ground segments are included in the total capital costs. The costs of developing a space segment are highlighted on the cost of developing a root satellite, a minivan-repeater, microscope. The same approach is also laid for the cost of exploitation of the space segment. When calculating the costs of the ground segment as the main component of earth stations, antenna systems, radio transmission microwaves and radio receiving microwaves, information processing devices, terminal equipment are taken as the main components of earth stations. The approximate cost of serial production of root sieuine, mini satellite, retrograder, microsatellite is indicated. The estimated cost of one minute of access in the studied combined LEO and in the existing "close" to the appointment of a low-bit satellite system is given.