Examining Metal Additives in a Marine Hybrid-Propellant, Water-Breathing Ramjet

Abstract

This research focuses on theoretically and experimentally evaluating the performance of a metallized hybrid-propellant, water-breathing ramjet. The aluminum and/or magnesium particles added to a polymeric (polyester) fuel grain are hydro-reactive, using the surrounding water as an oxidizer, in addition to a source of gas. Theoretically, the metal additives significantly increase the specific impulse of the motor, and as the percentage of the hydro-reactive ingredient increases, the theoretical performance increases as well. Additionally, aluminum is more energetic than magnesium. However, it was experimentally discovered that the addition of aluminum beyond 20% resulted in a slag formation and did not increase the specific impulse. Adding 30% of magnesium was relatively favorable to aluminum due to its better reactivity, enabling the achievement of an actual specific impulse of up to 485 s at standard conditions, approximately double the performance of common solid rockets.

High Calorific Values Boron Powder: Ignition and Combustion Mechanism, Surface Modification Strategies and Properties

“…In another kinetically controlled combustion mechanism, it can be assumed that the diffusion rate of O 2 is much faster than the reaction rate on the particle surface. At this time, the volume consumption rate, V kin , of boron particles per unit area can be written as Equation (5), and the combustion time, t kin , under kinetic control can be obtained by an integral using the same method as Equation ( 6):…”

“…Solid propellants and explosives with much higher energy performance are urgently needed in modern national defense technology [ 1 , 2 ]. Metal fuels have the advantages of high energy density [ 3 ], high combustion calorific value [ 4 ], and high-frequency combustion stability [ 5 ]; therefore, they have been widely used as high-energy additives to improve the energy density of energetic formulation systems [ 6 , 7 , 8 ]. The calorific values of Be, B, Mg, Al, Li, and other high-energy metal fuels are shown in Figure 1 .…”

Open-Sea Testing of Two-Phase Marine Ramjet Propulsion

“…Some of those works have been related to pump-operated waterjets. The ram rocket, a rocket-based water-breathing ramjet concept, has been investigated by Eisen and Gany [24][25][26]. Unlike the bubbly jet, where the gas mass fraction in the two-phase flow is a fraction of the percent of the water amount, the ram rocket concept aims at augmenting the thrust and energetic performance compared to that of a rocket at very high underwater cruise velocities.…”