Feasibility study and demonstration of an aluminum and ice solid propellant

Tyler David Wood, Purdue University

Abstract

Aluminum-water reactions have been proposed and studied for several decades for underwater propulsion systems, and other applications such as hydrogen generation. Aluminum and water mixtures have also been proposed as propellants and there have been proposals for other refrigerated propellants that could be mixed, frozen in place and used as solid propellants. However, little work has been done to determine the feasibility of these concepts. With the recent availability of nano-scale aluminum (nAl), a simple binary formulation of nAl and water is now plausible. Nano-scale aluminum has a lower ignition temperature than micron-sized aluminum particles, partly due to its high surface area, and burning times are much faster than micron Al. Previous research has shown that frozen nAl and ice mixtures are stable, as well as insensitive to electrostatic discharge, impact and shock. However, the feasibility of a nAl-ice (ALICE) propellant in small-scale rocket experiments has not been fully explored. It is the intent of this work to further the possibility and show the feasibility of using a frozen solid propellant to power a sounding rocket. The first part of this work outlines previous research related to the advancement of nAl and water propellants. In addition, previous research pertaining to the determination of propellant's mechanical properties is discussed. The experimental approach is reviewed for mixing large-scale ALICE propellant samples, testing center-perforated ALICE grains, and determining the mechanical properties of the propellant. The focus here is not to develop an optimized propellant, however improved formulations are possible and could be explored in future work. Additionally, a modeling code was written to both predict and complement the experimental data from the static test fires. Results of the static motor experiments reveal that the large-scale testing of the ALICE propellant is feasible. However, different methods of mixing the propellant produce dissimilar burning rate coefficients. The mechanical properties of the ALICE propellant are also determined, but further work needs to be performed to verify the findings. Finally, a specially designed flight weight casing is used in the first sounding rocket test of an aluminum-ice propellant, establishing the stepping stone of a refrigerated aluminum-ice propellant.

Degree

M.S.M.E.

Advisors

Pourpoint, Purdue University.

Subject Area

Mechanical engineering

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