Influence of Heat Release Value and Gaseous Combustion Products Content on Energetic Parameters of Solid Composite Propellants

摘要

There are two ways for the specific impulse (Isp) increasing— by the increasing of either heat release or efficiency. The first way may be realized using Al, Be, B and its derivatives or compounds with active fluorine, as well as using high formation enthalpy compounds. The second way may be realized by the change of propellant element content for increase the fraction of two-atomic gases in combustion products. The both methods have their advantages and drawbacks. Different ways to increase the SCP energetic parameters are considered. Concrete methods for energy rising are investigated –influence of the nature of oxidizer, binder, energetic compound, using aluminum and beryllium hydrides. If one increases the value ?°Hf of formulation in 100 kJ/kg the value of Isp increases in ～1.8 s for formulations with no metal, while for formulations with 20% Al the Isp growth is ～1.2 s only. In the same time increasing of the hydrogen fraction in 1 abs.% increases Isp of formulations with no metal in ～2 s, and formulations with 20% Al in ～6.5. The both methods have definite limits and may be accompanied with different negative consequences. Isp growth due to formation enthalpy increasing increases Isp higher than due to hydrogen fraction increasing. However it may increase drastically combustion temperature, and for decrease it to acceptable values one should introduce rather high amount of H-containing compounds and therefore the resulting Isp growth would be not so high. A comparative analysis of all ways to increase the energy of SCP is represented with the discussion of advantages and drawbacks of each of them in the context of the tasks for which the propellant is developed.