Powder feeding in a powder engine under different gas-solid ratios

It is a key and difficult problem to find the optimal powder-feeding technique in the study of powdered engines. In this paper, the feeding of powder in powder engines at different gas-solid ratios was experimentally investigated. Working characteristics of the classic piston-driven powder feeding system were obtained. A high linear tendency between powder mass flow rate and the minimum throttle channel area is observed from the experiment. The solid-gas mass ratio to maintain a stable powder feeding is approximately valued in range of 34.4–54.6 under different throttle channel areas. The least deviation in the relative powder mass flow rate for the tests is −15% to +8%. Due to the high uncertainty of the gas-solid flow structures at different gas-solid ratios, obvious low-frequency oscillations and high-frequency oscillations exist during the powder feeding process. The frequencies of low-frequency oscillations are mainly 1–3 Hz, while those of high-frequency oscillations are 20–30 Hz and 30–45 Hz in different tests.