Study of a Propulsive Nozzle for a Ship Directly Driven by High-Pressure Wave Generated by Air-Propane Mixture Combustion

Abstract

We propose a new type of propulsive equipment for a ship in this paper. It is directly driven by the high-pressure wave generated by air-propane mixture combustion. The propulsive equipment is a simple structure consisting of a combustion tube and a semi-open-type nozzle. In order to clarify the mechanism of thrust generation, we measured the pressure fluctuation on the nozzle wall and the thrust for various angles of ejecting the pressure wave, and also we observed the flow in the two-dimensional nozzle by using a high speed motion camera. Water flow in the nozzle is accelerated momentarily by the pressure wave, and the bubble is exhausted to downstream while their expansion. It was clarified that the thrust strongly depends on the nozzle-wall angle, and the thrust for the nozzle-wall angle 45 degrees is higher than others in this experiment. The thrust of the nozzle was 42 N when the 400 kPa pressure wave is driven with added oxygen.