Influence of Al-Ni alloy on the combustion and agglomeration of solid propellants

Aluminum alloy powder offers a promising approach to regulating propellant performance. A comparative analysis was conducted on the thermal oxidation, ignition, and self-sustaining combustion characteristics of aluminum-nickel alloy and aluminum powder, utilizing synchronous thermal analysis experiments (TG-DSC) and a laser ignition testing system. Subsequently, a series of experiments were conducted, involving thermocouple temperature measurement systems, high-pressure photography systems, condensed combustion products (CCPs) analysis, and chemical titration. These experiments investigated how varying aluminum-nickel alloy compositions affect the combustion, agglomeration, and combustion efficiency of propellants. The results demonstrated that the addition of trace amounts of nickel can increased the oxidation weight gain of aluminum powder from 5 % to 82 % within 1200 °C. And it significantly accelerated the oxidation rate and enhanced the heat release by two orders of magnitude. The aluminum-nickel alloy also exhibited a considerable reduction in the ignition delay time and a significant increase in the duration of self-sustaining combustion. In terms of combustion performance, the aluminum-nickel alloy raised the temperature gradient by approximately 65 %. Furthermore, the burning rate showed a positive correlation with the aluminum-nickel alloy content, while the pressure exponent remained consistent. Additionally, the alloy effectively reduced propellant agglomeration, leading to a decrease in agglomeration and an approximate 1.8 % improvement in combustion efficiency. In summary, the results reveal the influence and mechanism of aluminum-nickel alloy on propellants, which can promote the engineering application in propulsion systems.