PERFORMANCE ANALYSIS of WATERJET PROPULSION on AN UNMANNED SURFACE VEHICLE MODEL

Waterjet propulsion on an unmanned surface vehicle is a propulsion system with the working principle of taking water from the bottom of the hull into a turbine to be blown out the back, converted into the ship's thrust. The resulting thrust depends on the available water forces. The water spray in the nozzle is generated from an inlet at the bottom of the ship, which is assisted by a pump on the waterjet. In the inlet section, this will affect the distribution of flow that passes through the pump and out through the nozzle. The purpose of this study was to analyze the inlet passage of the jet of water, which is variable, with the inlet velocity ratio (IVR) to determine the maximum efficiency value of the waterjet propulsion system. The work of this study used the computational fluid dynamics (CFD) method and analytical calculations. The inlet velocity ratio was varied with values of 0.54, 0.59, 0.67, 0.78, 0.94, 1.18, 1.64, and 2.38. The results of the analysis included the volume that exited the waterjet outlet and the thrust value under different conditions. The highest thrust value obtained was based on an IVR value of 2.38, which also had the maximum efficiency value of 98%.