Feasibility study of jet propulsion for remote operated underwater vehicles

Abstract

This thesis is a feasibility study of jet propulsion for remote operated vehicles (ROV’s). The concept of using a tilting type nozzle for improved maneuverability is discussed. Though the propulsion efficiency of jets is less compared to that of the propeller for the velocity ranges usually encountered in ROV movements, the implementation of jet propulsion is considered in view of the advantages in improving maneuvering qualities. Also, the simplicity of the system and les complexity in pressure compensation adds to its advantages. This study concentrates on the selection of an optimum nozzle configuration for ROV’s. -- An experimental set-up was designed and fabricated for this investigation. Ten different plexi-glass conical nozzles were used for five different circular disk shaped drag plates, simulating the drag of the ROV motion under water. Energy losses were determined both experimentally and theoretically. Wall effects encountered in the experimental tank were compensated by towing the model in an open water wave tank for the same range of speeds. It was found that the propulsion efficiency is maximum for one particular nozzle over a wide range of flow rates encountered in the experiments. Finally, a feasible design of a jet propelled ROV with tilting type nozzles is presented. This design could be fabricated and tested for commercial production.