The RD -253 ( двигатель of Russian Реактивный, " Reaktiwny Dwigatel " ) ( GRAU index 11D48 ) is a rocket engine for liquid rocket.
Development and use
It was developed by the Soviet chief engineer for rocket motors Valentin Petrovich Glushko in the period 1961-1965 at the Leningrad gas dynamic laboratory. Six of them serve in the Proton rocket as a drive for the first stage.
It is with 1,1- dimethylhydrazine ( UDMH ) and liquid nitrogen tetroxide operated ( N2O4 ) and consists of a pre-and a main combustion chamber, a turbine and an auxiliary and two main pumps with a total of 18.7 MW. The special feature of this engine is that the turbine is arranged to drive the fuel pump inside the precombustion chamber. To the total amount of oxidant and a small amount of fuel is supplied, which burns there with a low temperature and the turbine. The exhaust gas then passes from the combustion prechamber to the main combustion chamber where the main part of the fuel is fed and burns. By this embodiment the engine is not drive-gas for the pump is also at the high combustion chamber pressure of 15 MPa almost lost, which would have resulted in a rate of more than 520 kg / s in considerable losses. Simultaneously, the high degree of combustion instability during combustion, and thus combustion oscillation includes largely by the pilot and main combustion. The special design of the RD -253 were the dimensions and mass of the engine compared to a comparable engine, the design of the RD -107 would have met, be kept low.
Despite some problems with the first development and production of the RD- 253 is still used today in the Proton rocket. Meanwhile, almost 2000 pieces of which have been built. Of these, some in improved versions such as the RD -275 (GRAY index 14D14 ) ( after 1990 ) with 1578/1746 kN and 15.7 MPa Boden-/Vakuumschub combustion chamber pressure and the RD- 275M ( GRAU index 14D14M, sometimes with RD -276 ) having is further increased by 5% takeoff thrust, which is a Proton -M had his first start in July 2007.