Modeling of water flow for waterjet propulsion system

Abstract

The paper provides simulation results for water flow ratio in the waterjet attached to the SUP (Stand Up Paddle) board fin. The goal of the project is to attach the waterjet propulsion to the SUP board with maximum efficiency. To do it, the model of the person driving the board and waterjet was created in SolidWorks. In this paper the water flow rate depending on different nozzle and duct design was analysed. There are two conflicting requirements for the propulsion duct design. On the one hand, the duct must protect the propulsor from stones and water plants, because SUP boards travel on rivers, sometimes very close to stones. On the other hand, the efficiency of the waterjet requires maximum water flow rate available for a possibly greater Inlet Velocity Ratio. Finally, there should be enough place for the battery pack, which drives the waterjet, but it creates an additional barrier for the water flow. The flow rate at the outlet depends on the nozzle and is also important for the propulsor efficiency. Variable design options for the waterjet duct were proposed and tested in SolidWorks Flow simulation environment. At the beginning of the project there was an intention to create different ducts via 3D printing. The simulation showed that modification of the inlet duct results in minor (only 0.01%) increase of the flow rate, if the front panel remains closed due to the oblique stagnation point flow phenomenon, and 3D printing resources should not be wasted on this test.