Nitric acid oxidizers - a category of components of long-life liquid rocket fuel used as an oxidizing agent , the main component of which is nitric acid . They are used in military rockets, space launch vehicles and spacecraft, where the use of liquid oxygen is impossible or impractical because of its evaporation.
The most common nitric acid oxidizer in Russia (in the USSR) is AK-27I , which is a solution (“ melange ”) of 27% (by weight) nitric tetraoxide (AT, N 2 O 4 ) in nitric acid (AK, HNO 3 ) with the addition of corrosion inhibitor - crystalline iodine . In addition to Soviet missile systems, it was also used in Chinese combat missiles and the first launch vehicles in the 1960s and 1970s.
In the Soviet anti-aircraft missile systems, the AK-20I oxidizer was also used, which was characterized by a lower AT content (20%), which increased the density and expanded the operating temperature range, but reduced the specific impulse . In the USA, solutions of AT in AK with an AT concentration of about 14%, called “ red fuming nitric acid, ” or RFNA, were also used .
Such a mixture surpasses pure nitric acid in operational properties and specific impulse, but, as a result, AK-27I type oxidizers were displaced with pure nitric tetroxide, since it provided a higher specific impulse , and the high freezing temperature of AT was counterbalanced by thermostating of military missiles in mines or heated AT before refueling launch vehicles (e.g. Proton ).
The use of nitric acid oxidizing agents in combat missile systems allowed them to be kept in a tucked-in state for a long time, and in the case of amplification , their entire service life. Now, however, the use of nitric acid oxidizers in combat missiles manufactured by the USSR in the Russian Federation has been very limited (to date in the Kyrgyz Republic X-22 ). Massive use has been preserved mainly only in third world countries that operate clones of Scud missiles ( R-11 and R-17 ) - the rest switched to using mixed solid fuel both in ballistic missiles and in missiles . Pure nitrogen tetraoxide is used mainly in propulsion systems of spacecraft.
Content
Compositions
- AK27I : 69.8–70.2% HNO 3 , 24-28% N 2 O 4 , inhibitor I - 0.12-0.16%, H 2 O - 1.3-2.0% [1]
- AK27P : 69.5% HNO 3 , 24-28% N 2 O 4 , 0.3-0.55% HF , 0.05-0.15% H 3 PO 4 , up to 1.4% H 2 O [ 2]
- AK-20 : 80% HNO 3 , 20% N 2 O 4
- AK20I : 72.9% HNO 3 , 17.5-22.5% N 2 O 4 , 0.15-0.25% inhibitor I, up to 0.04% Al 2 O 3 , 3.3-4.3 % H 2 O
- AK20K : 73% HNO 3 , 17.5-22.5% N 2 O 4 , 0.5-0.75% HF, 1.0-1.3% H 3 PO 4 , 2.1% H 2 O
- AK20F : 73.5% HNO 3 , 17.5-22.5% N 2 O 4 , 0.5-0.8% HF, 0.8-1.1% H 3 PO 4 , 1.2-2 , 8% H 2 O
- AK20II : 69.8% HNO 3 , 24-28% N 2 O 4 , 0.12-0.16% inhibitor I, up to 0.03% Al 2 O 3 , up to 1.7% H 2 O
- IRFNA IIIa : 83.4% HNO 3 , 14% NO 2 , 2% H 2 O , 0.6% HF
- IRFNA IV HDA : 54.3% HNO 3 , 44% NO 2 , 1% H 2 O, 0.7% HF
- S-Stoff : 90-97% HNO 3 , 3-10% H 2 SO 4 or FeCl 3
- SV-Stoff ( Salbei ): 94% HNO 3 , 6% N 2 O 4
See also
- Red fuming nitric acid
Notes
- ↑ GOST B 18112–72 according to http://military.tomsk.ru/blog/topic-177.html
- ↑ http://www.osce.org/en/fsc/35906 Liquid rocket fuel in the OSCE region: overview of recycling aspects
Links
- Andrey Suvorov. Secret fuel: Food of the gods . Popular Mechanics (November 2006). Date of treatment August 29, 2010. Archived March 24, 2012.