A system and method of combusting aluminium comprising i) feeding aluminium wire to a substantially oxygen-free furnace comprising a. a first low-temperature section in communication with b. a second high-temperature section ii) forming aluminium particles with an average particle size ranging from 1 .Math. to 200 .Math. from said aluminium wire in said first section iii) feeding water and/or steam to said first and/or second section to provide an oxidizer for oxidizing said aluminium particles in the second section iv) conveying aluminium particles from the first section to the second section v) oxidizing said aluminium particles in the presence of steam in said second section.

A system and method of combusting aluminium comprising i) feeding aluminium wire to a substantially oxygen-free furnace comprising a. a first low-temperature section in communication with b. a second high-temperature section ii) forming aluminium particles with an average particle size ranging from 1 m to 200 m from said aluminium wire in said first section iii) feeding water and/or steam to said first and/or second section to provide an oxidizer for oxidizing said aluminium particles in the second section iv) conveying aluminium particles from the first section to the second section v) oxidizing said aluminium particles in the presence of steam in said second section.

A method for underwater propulsion including a thermal engine system wherein the thermal engine system produces a propulsion gas, the propulsion gas is introduced into a pressure tuned valve, wherein the pressure tuned valve lies upstream of an eductor and the pressure tuned valve controls release of the gas from the thermal engine system to the eductor; and wherein the release of the propulsion gas to the eductor provides underwater propulsion by ejection of the propulsion gas into surrounding water.

A method for underwater propulsion including a thermal engine system wherein the thermal engine system produces a propulsion gas, the propulsion gas is introduced into a pressure tuned valve, wherein the pressure tuned valve lies upstream of an eductor and the pressure tuned valve controls release of the gas from the thermal engine system to the eductor; and wherein the release of the propulsion gas to the eductor provides underwater propulsion by ejection of the propulsion gas into surrounding water.