Torque Balance and Cavitation Studies on Underwater Vehicle Propulsion System

Cavitation is the prime enemy for high speed underwater vehicles, which limits the vehicle speed and effect on its efficiency in terms of speed, power and noise. Conventional propellers fail to generate the thrust required to propel the vehicle beyond certain speeds due to onset of cavitation. To overcome the limitations imposed by conventional propellers, the state of the art Pumpjet propulsion system is being used for high speed underwater vehicles. A Pumpjet propulsor has been designed for high speed underwater vehicle, validated its performance through model tests at hydrodynamic test facilities. Propulsion tests are conducted at High Speed Towing Tank to estimate the power delivered for different operating speeds. Torque balance tests and cavitation tests are conducted at Cavitation Tunnel to estimate the imbalance torque between rotor and stator and cavitation inception depths of Pumpjet propulsor for different operating speeds. The present paper describes in detail about the cavitation performance of Pumpjet propulsor, imbalance torque between rotor and stator and correction methods adopted for improving its performance.