Effects of acceleration overload on combustion characteristics of HTPB/AP/Al propellant

In order to study the effect of acceleration field on the combustion characteristics of HTPB/AP/Al propellant, an overload test rocket with both burning rate measurement and condensate product collection functions was designed. The effects of different overload magnitudes (−50g to +50g) on combustion chamber pressure, mean combustion velocity, transient combustion velocity, condensed phase products and rocket plume were investigated by using the overload test method. The research showed that: (1) the reverse overload had little effect on the pressure of the combustion chamber and the burning rate of the propellant. With the increase of forward overload, the combustion chamber pressure and propellant burning rate increased. (2) Compared with that without overload, the combustion chamber pressure increased by 35.8% under +10g overload, 69.9% under +30g overload, and 76.8% under +50g overload, and there was a hump phenomenon under +30g overload and +50g overload. (3) Compared with 0g, the burning rate increased by 21% under +10g overload, 40% under +30g overload, and 44% under +50g overload. At +30g and +50g overload, the transient combustion velocity increased and then decreased, the maximum value increased with the increasing overload, the time to reach the maximum value decreased with the increasing overload. (4) The content of carbon and elemental aluminum in the medicine cup decreased by 100% and 82.28%, respectively, with the increase of positive overload, and the alumina increased by 402.17% with the increase of positive overload. There was almost no carbon and aluminum in the collection device. And the particle size of the condensed-phase product in the collection device decreased with the increase of positive overload. (5) Acceleration field had a significant effect on the color of rocket plume; under reverse overload, the engine plume flame appeared yellow accompanied by bright sparks; under forward overload, it appeared purple. © 2024 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.