Rheological performance and castability criteria of AlH3 high energy propellant
The rheological performance of AlH3 high energy propellant slurry during the applicable period was investigated by using vacuum spray casting equipment and rheological testing methods,and the relationship among viscosity,yield value and castability of the slurry at different casting time was explored.The experimental results showed that the viscosity of the slurry increased,the shear rate index decreased,and the pseudo plasticity increased with the increase of casting time.The change rule of the slurry viscosity with the casting time could be described more accurately by the empirical formula ηt=η0+atb.The relationship among the slurry viscosity,shear rate and yield value could be more accurately described by the rheological constitutive equation Herschel-Bulkley.The criteria for castability of AlH3 high energy propellant were as follows:the slurry could be cast when the slurry viscosity was below 355.7 Pa·s,the yield value was below 82.3 Pa,and the leveling area per unit mass was above 0.823 cm2/g;the slurry could not be cast when the slurry viscosity was above 491.4 Pa·s,the yield value was above 117.6 Pa,and the leveling area per unit mass was below 0.739 cm2/g.