Peculiarities of the working process of low-thrust hypergolic-propellant liquid rocket engines with a thrust of less than 1 N

Abstract

The article presents the results of theoretical and experimental studies of the peculiarities of the working process of low-thrust hypergolic- propellant liquid rocket engines (LTLRE) with the thrust of less than 1 N. We also discuss ways of improving their efficiency, reliability and stability of parameters. To study the stability of the hydraulic characteristics of LTLRE capillary nozzle elements we experimentally investigated the hydrodynamic characteristics of the capillaries under conditions of isothermal flow of water and heat supply and proposed a method of their calculation. Using the proposed calculation method we studied the changes of the capillary hydraulic resistance for the engine injector head and showed that the effect of thermal factors can lead to significant changes in the hydraulic characteristics of nozzle elements of engines with the thrust of less than 1 N and, consequently, to the instability of its parameters and off-design engine operation. A theoretical and simulation study was carried out to determine the region of total liquid-phase mixing depending on the capillary diameter and the thrust of the engine. It is shown that low efficiency of liquid-phase mixing of the components is the main reason for the low efficiency of LTLRE with the thrust of less than 1 N. We investigated experimentally the variation of energy parameters of a jet-mixing engine with the thrust of less than 1 N depending on the thrust level. We propose to use a precombustion chamber as a possible way of intensifying the intrachamber workflow. The influence of prechamber on the energy parameters of a LTLRE with the thrust of less than 1 N is analyzed. The possibility of intensifying the intrachamber workflow with the use of a prechamber is shown. Recommendations on the choice of the geometry of the prechamber are given.