Investigation of nozzle two-phase flow characteristics for nanometer aluminum powder combustion in a metal fuel motor

Abstract

Nanometer aluminum powder is a promising new type of fuel that could be the subject of tremendous practical and research interest for future waterborne traffic. To better optimize the design of an engine of an underwater system, this study was devoted to the characteristic investigation of a two-phase flow. It was found that the variation in the size and coagulation content of the particles played a significant role in the loss of the two-phase flow. By establishing a combustion model for the particles and governing equations for the two-phase flow, a theoretical study was performed to analyze the combustion properties of alumina particles and flow in the nozzle. Significant emphasis was placed on the effect of particle sizes (ranging from 0.4 to 0.95 μm) and coagulation content (from 12% to 48%) of ultrafine particles on the specific impulse. To further validate the theoretical results, experiments were conducted, and the results showed good agreement with the experimental data. The results demonstrate that the mean specific impulse of the engine can be as high as 4900 N.s/kg, with condensed phase content and particle sizes of approximately 36% and 0.40–0.70 μm, respectively.