Thrust production from in-water gas charge combustion near a flat wall

Abstract

The paper presents experimental results on study of production of force pulses and bubble pulsation near a flat thrust-producing wall with the diameter of 100 mm designed for combustion of stoichiometric propane-oxygen gas mixture. In combustion of the same gas charges for production of thrust, the design of combustion at a flat wall has qualitative and quantitative benefits vs. case of combustion in a cylindrical duct. The force amplitude becomes higher due to the larger contact area between the bubble and thrust wall. The period of bubble pulsation is shorter for this case as compared to bubbles generated in a cylindrical duct; the pulsation period is described by the Rayleigh-Willis law. The shorter bubble pulsation period ensures better conditions for increase in the average thrust generated in pulse-in-cycle mode of combustion of gas charges in water medium.