Experimental study on particles directed transport by an alternating travelling-wave electrostatic field

A continuous and controllable lunar regolith directed transport is crucial for the development of the 3D printing technology on the moon. The electrostatic method becomes a promising particle transport method for the extraterrestrial environment due to its irreplaceable advantages over other traditional methods. In this paper, particle directed transport by an alternating four-phase travelling-wave electrostatic field is experimentally investigated. Great efforts are made to carefully present the detailed particle movement trajectories and to deeply understand the particle control mechanism of the electrostatic method. It is found that not only the excitation frequency would affect the particles' transport direction, but also the voltage amplitude and geometric parameters would change the transport direction. For the present experiments, the backward transport of lunar regolith simulant can be realized at the low frequency conditions (2– 30 Hz). By post-processing of the recorded pictures, the detailed particle behaviors and the changes of the particles' velocity vector distribution with the electrostatic field propagation are obtained. The formation processes of both the forward and backward directed transports of particles are carefully demonstrated and discussed. Based on the obtained results, the most important part of particles, which plays a great role in the directed transport formation in an alternating electrostatic field, is determined and valuable investigation suggestion is proposed. Additionally, the impacts of the key influencing parameters on particle transport performance are obtained.