RD-253
The RD-253 (from Russian Ракетный двигатель , "Raketnyj dwigatel") ( GRAU index 11D48) is a rocket engine for liquid rockets .
Development and use
It was developed by the Soviet chief designer for rocket motors Valentin Petrovich Glushko between 1961 and 1965 at the Leningrad gas dynamics laboratory . Six of them are used in the Proton rocket to drive the first stage .
technology
It is operated with 1,1-dimethylhydrazine (UDMH) and liquid nitrogen tetroxide (N 2 O 4 ) and consists of an upstream and a main combustion chamber , a turbine and an auxiliary and two main pumps with a total output of 18.7 MW. The specialty of this engine is that the turbine for driving the fuel pumps is located inside the pre-combustion chamber. For this purpose, the entire amount of the oxidizer and a small part of the fuel is fed, which burns there at a low temperature and drives the turbine. The exhaust gas from the pre-combustion chamber then passes to the main combustion chamber, where the main part of the fuel is supplied and burns. With this design, the engine does not lose any drive gas for the pumps, even at the high combustion chamber pressure of almost 15 MPa, which would have led to considerable losses at a throughput of more than 520 kg / s. At the same time, the high degree of combustion due to the pre- combustion and main combustion largely excludes instabilities during combustion and thus combustion oscillations. Due to the special design of the RD-253, the dimensions and the mass of the engine could be kept low compared to a comparable engine, the design of which would have corresponded to that of the RD-107 .
Despite some problems with initial development and production, the RD-253 is still used in Proton launch vehicles today. Almost 2,000 of them have now been built. Some of them in improved versions such as the RD-275 (GRAU index 14D14) (after 1990) with 1578/1746 kN floor / vacuum thrust and 15.7 MPa combustion chamber pressure and the RD-275M (GRAU index 14D14M, sometimes also with RD -276 ) with a further 5% increase in take-off thrust, which had its first launch in July 2007 with a Proton-M.
Technical specifications
Code number | value |
---|---|
Mixing ratio N 2 O 4 / UDMH | 2.67 |
Combustion chambers | 1 |
Total height | 2.72 m |
diameter | 1.5 m |
Dry matter | 1280 kg |
Mass / thrust ratio (ground / vacuum) | 0.87 / 0.78 kg / kN |
Combustion chamber diameter | 430 mm |
Combustion chamber pressure | 14.7 MPa |
Nozzle throat diameter | 279.7 mm |
Nozzle mouth diameter | 1431 mm |
Orifice pressure | 61 kPa |
Relaxation relationship | 241 |
Floor thrust / vacuum thrust | 1474/1635 kN |
Specific impulse (soil / vacuum) | 2795/3100 Ns / kg |
literature
- Peter Stache, Russian rockets , ISBN 3-327-00302-5
Web links
- RD-253 ( Memento from April 29, 2014 in the Internet Archive ) at the manufacturer Energomash (English)
- RD-253 in the Encyclopedia Astronautica (English)
- Bernd Leitenberger: Article about the Proton rocket
swell
- ЖРД РД-253 (11Д43) и РД-275 (14Д14). Liquid Propellant Rocket Engines, accessed March 19, 2009 (Russian).