50 n thrust correction engine for the "Luna-resurs" lunar module descent engine

Research to develop a 50 N thrust correction low-thrust liquid rocket engine with a deflector-centrifugal scheme of mixing nitrogen tetroxide and unsymmetrical dimethylhydrazine propellants on the inner wall of the combustion chamber has been conducted at the Chemical Machinery Design Bureau named after A.M. Isaev. In the deflector-centrifugal mixing scheme developed at the Chemical Machinery Design Bureau the oxidizer gets to the conical deflector via the jet nozzle and is transformed into a primary film running off the edge of the deflector onto the inner wall of the combustion chamber where it is transformed into a secondary film that flows along the wall of the chamber to the point of meeting the film from the centrifugal fuel spray nozzle coaxial with the combustion chamber. Upon meeting the films of oxidizer and fuel continue flowing along the wall of the combustion chamber at the same time penetrating each other and carrying out the liquid-phase mixing with the formation of transformation products of hypergolic fuel. Thus, practically all the fuel gets to the inner wall of the combustion chamber, participating in its cooling and removal of a considerable part of the heat flow directed along the wall of the combustion chamber from its critical section in the direction of the nozzle head. The engine has the highest (in its class) geometric nozzle expansion ratio ( Fа =200) among analogues of domestic production, meanwhile preserving acceptable dimensions and weight characteristics. The combustion chamber in the engine designed is made of a niobium alloy with a protective heat resistant coating - molybdenum disilicide MoSi2 deposited on the inner surface while niobium disilicide NbSi2 formed by silicon impregnation of a niobium alloy is used on the outer surface. During the firing tests the jet centrifugal scheme of organizing the work process in the combustion chamber designed at the Chemical Machinery Design Bureau confirmed its efficiency in a 50 N-thrust engine. The adopted design and technological solutions in creating a 50N thrust engine ensured high power and energy-mass characteristics, as well as stable engine performance in a wide range of pressures of fuel entering the engine: up to 70.3 N in power augmentation and up to 45.9 N in throttling