This paper presents a calculation and experimental estimation of the efficiency of using lithium, sodium, magnesium, and aluminum as fuels in hydro-reactive propellants. The study shows that the specific fuel consumption is of primary importance in power motor units (PMU) for underwater vehicles (UV) using hydro-reactive propellants based on lithium or sodium to ensure the required high performance. As a result of using melted lithium, a PMU providing the UV with higher propulsive characteristics can be created. It is shown that the use of Mgbased fuel leads to a significant reduction in the UV range and the PMU specific impulse compared to the use of Al-based fuel. The use of aluminum-seawater propellant in a PMU makes it possible to double the values of UV characteristics at moderate depths and improve them by 25% at great depths. Studies of aluminum application in UV PMUs seem promising, and additional development will be mainly required for the design of the combustion chamber and fuel supply system elements. In the suggested scheme of a supply system feeding aluminum to the PMU combustion chamber, aluminum is fed (pressed) into the combustion chamber in the form of a hot melted metal, which reacts with seawater. It is shown that aluminum-seawater propellant is the most effective compared to other types of UV propellants and the most promising for further development.
