Thermal Propulsion Engine For Heavy Weight Torpedoes

Naval Science & Technological Laboratory (NSTL), Visakhapatnam, is developing an advanced Thermal Propulsion Engine for Heavy Weight Torpedoes. Technology demonstration trials at test bed have been completed for this state-of-the-art-technology and the torpedo configuration is ready for evaluation trials at sea. This air independent propulsion system uses a liquid mono-propellant called high-energy fuel as energy source and single stage axial flow impulse partial admission turbine as the prime mover. This compact turbine runs at a very high speed of 50,000 rpm. The high speed of turbine is reduced to propeller speed using a two-speed reduction gearbox. This also has high-pressure liquid mono-propellant fuel pump which can develop pressure up to 400 bar, and is mounted on the gear box pod. This propulsion system also uses a pump stack mounted on gearbox pod. This propulsion system also uses a pump stack mounted on gearbox pod. The pump stack contains a seawater pump, a hydraulic pump and two lub oil pumps stacked together and driven by a single shaft.

Hydraulic pump supplies oil at a pressure of 210 bar to the hydraulic fin actuation system and also to the servo valves, which runs in a closed circuit. Lub oil is used for lubrication and cooling of gears and oil is cooled in a compact heat exchanger and is re-circulated. Seawater pump, draws the water to cater to all the cooling requirements of hot gas components. This whole engine occupies a length of 1170 mm and weighs about 235 kgf.