Design, fabrication and fine-tuning of an aerial-aquatic explosive water-jet thruster with repeatable propulsion capability

Water-jet propulsion helps flying squid shoot quickly from underwater into the air, overcoming the huge differences in density and viscosity between two fluids. To get faster underwater takeoff, water-jet propulsion can be great inspiration for the design of new propulsion system for aquatic unmanned aerial vehicle (AquaUAV). In this paper, an novel aerial-aquatic water-jet thruster is developed and fabricated, which uses butane and oxygen to realize explosive water-jet. An unit butane cell and oxygen cell can satisfy more than 50 explosions without replacement of components. We designed different fine-tuning strategies for the two gas supply, designed and completed experiments to obtain stable gas supply and controllable explosion. And the optimized supply systems were tested on the force measurement system. For the first time, our new thruster achieved underwater no-exchange-air explosion, which may help AquaUAV handle continuous underwater explosive propulsion and repeatable launches other than propellers.