Closed-loop cooling system for a hydrogen/oxygen based combustor

A closed-loop cooling system is provided for a hydrogen/oxygen based combustor. A combustion reaction between hydrogen and oxygen in the combustor produces steam. The steam is used to generate work from a turbine shaft, which is used to drive a propulsion system for the underwater vessel. After the steam passes through the turbine, the steam is cooled back to liquid water by a condenser that uses a seawater cooling loop to cool the steam into cold water. The cold water is then injected into the combustor, and pumped into passages along the walls of the combustor, thus absorbing the heat. The cold water absorbs this heat until it becomes hot water or steam, which is then injected into the combustor with the hydrogen and oxygen to act as a diluent, thus reducing the reaction temperature of the hydrogen/oxygen combustion reaction. The reaction produces more steam, and the cycle repeats.