Design and analysis of vacuum air-intake device used in air-breathing electric propulsion

In this study, a vacuum air-intake device with an inlet diameter of 500 mm is designed for collecting space gas as the propellant of the air-breathing electric thruster, and it is comprised of a multi-hole plate, a big turbo, a small turbomolecular pump and a miniature scroll pump in series. The space gas collection efficiency of the vacuum air-intake device is mainly determined by the performances of the multi-hole plate and the big turbo, which are investigated by Monte Carlo method; the storage of the collected gas with high pressure is mainly achieved by the small turbomolecular pump and the miniature scroll pump, which are analyzed experimentally. The computation results of direct simulation Monte Carlo (DSMC) show that, the collection efficiencies of the high and the low rotational speed cases are 56.47%-57.85% and 41.67%-42.60% at the altitudes of 150-240 km, respectively; the turbo's powers of the high and the low rotational speed cases for gas drag compensation are no more than 52.6 W and 12.3 W, respectively. The experimental results indicate that, the small turbomolecular pump (weight: 5.7 kg) and the miniature scroll pump (weight: 0.84 kg) can quite efficiently compress the collected gas, and get an atmospheric pressure (8.5 x 10(4) Pa, in Lanzhou); the total power of the two pumps is 27.1-150.3 W at the gas flux of 0-50 sccm. (C) 2015 Elsevier Ltd. All rights reserved.