Abstract
The application of the Knudsen pump to the thruster for the orbital control system is considered. This is a kind of the “fuel-free” type thruster using the ambient rarefied gas around a spacecraft as the propellant. The thrust is produced due to the thermal transpiration flow in the pump, which is the characteristic flow in the rarefied regime. In this paper, the basic behavior of the Knudsen pump, which operates in a high speed and highly rarefied gas flow, is numerically investigated using the direct simulation Monte Carlo (DSMC) method to confirm its efficiency as a thruster. The dependency of the skin friction on the Knudsen number, the velocity of the inflow and the temperature distribution on the channel wall is clarified. It is found that a tendency of the variation of the drag reduction rate with the increase of the Knudsen number in the case of the inflow velocity at 1 km/s is different from that at 8 km/s.
