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EN
The novel liquid fuel 2-dimethylaminoethyl azide (DMAZ) is a good candidate for the replacement of the hydrazine family in space programs. However, it suffers from low electrical conductivity, which is dangerous during the production process and its transportation. A simple and effective way to increase its electrical conductivity is the use of antistatic additives. In this article, the electrical conductivity of DMAZ was initially predicted via an artificial neural network. Then, the increase in electrical conductivity of DMAZ was investigated using some chemical surfactants (such as hexylamine, octylamine and tributylamine), acetonitrile as a polar aprotic substance and a DMAZ salt (DMAZ·HCl) as an ionic liquid. Of these additives, acetonitrile had the greatest effect on the electrical conductivity of the fuel, exhibiting an increase in conductivity of about 45%. Adding a two-component mixture of acetonitrile and the DMAZ salt, further increased the electrical conductivity of the fuel by about 55%, relative to pure DMAZ. Tributylamine did not have a significant effect on the electrical conductivity of the fuel.
EN
Dimethylaminoethyl azide (DMAZ) is a good replacement for the hydrazine group in the space industry. However, it has a relatively long ignition delay time with the liquid oxidizer, white fuming nitric acid (WFNA), and is nonhypergolic with inhibited red fuming nitric acid (IRFNA). In this article, the ignition delay times of DMAZ-WFNA and DMAZ-IRFNA bi-propellants were reduced by the addition of some inorganic nitrate salts, such as NH4NO3, KNO3, NaNO3, AgNO3 and LiNO3, to the liquid oxidizers. The results showed that WFNA containing 0.1 wt.%, 0.3 wt.% and 0.5 wt.% of LiNO3 reduced the ignition delay time of DMAZ-WFNA from 88 ms to 18 ms, 14 ms and 8 ms, respectively. The same percentages of LiNO3 caused the nonhypergolic DMAZ-IRFNA bi-propellant to have ignition delay times of 42 ms, 34 ms and 22 ms, respectively. Moreover, calculations indicated that the addition of LiNO3 to both oxidizers did not have a significant affect on the specific impulse of the bi-propellants. Consequently LiNO3 could be an appropriate additive for the reduction of the ignition delay times of DMAZ-WFNA and DMAZ-IRFNA bi-propellants.
EN
2-Dimethylaminoethyl azide (DMAZ) is a good replacement for the hydrazine family in space industries. In this article, the accelerated ageing test method was applied for predicting the shelf life of DMAZ. The effective parameters on the storage of the fuel were temperature, the type of gas atmosphere with its pressure over the liquid fuel, and moisture. Appropriate conditions for DMAZ storage were N2 at a pressure of 3 bar and a moisture content of 0.05 wt.%. The sigmoid form of the decomposition curves obtained revealed that the decomposition reaction is autocatalytic. Modelling of the decomposition rate showed that the shelf life of DMAZ was 7.73 years at 25 °C.
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