Effect of non-spherical particles on nozzle two-phase flow loss in nano-iron powder metal fuel motor

Metal iron powder is a promising new energy source that is of significant practical and research interest for future automotive power systems. However, the shapes of the particles are typically assumed to be spherical or an equivalent sphere when estimating the specific impulse of motors. Such an assumption lacks objectivity and can result in unreasonable estimations of two-phase flow losses. In order to better optimize the design of an engine, this study focuses on the influence of non-spherical particles (such as ellipsoidal and cuboid particles) on the characteristics of nozzle two-phase flow. Models for the governing equations of nozzle two-phase flow are developed to conduct a theoretical study to analyze the combustion properties of iron oxide particles and flow in the nozzle. In addition, experimental studies involving nanometer iron-powder particle combustion and engine thrust measurements are conducted to validate the results obtained from numerical calculations that are conducted using a fourth order Runge-Kutta-Gill method. The results indicate that particle morphology, size, and coagulation content play a significant role in the motor performance and the two-phase flow losses. Specifically, the hypothesis of the ellipsoidal model is in better agreement with the experimental findings compared to the other particle models. (C) 2019 Elsevier Masson SAS. All rights reserved.