Electrohydrodynamic propeller for in-atmosphere propulsion; rotational device first flight

Abstract

Attempts to use Electrohydrodynamic (EHD) flow for propulsion have been made since the last century 1 . Limited success has been registered particularly due to the inhomogeneous generation of the thrust, and also the very light weight and frail nature of the devices versus the power supply weight needed hover the craft 2 . However, EHD propulsion can offer a greater thrust to power ratio than any of the current propulsion technologies 3 . Rotary EHD devices have been employed as demo units for a long time 4,5 , but it was unknown if they could produce enough thrust and vertical lift to lead to device liftoff. We designed EHD propellers which spin and eventually lift off and fly independently for a short while. The propeller is balanced on and powered through a high voltage pin/shaft while an intense electric field is created by the presence of a surrounding ground electrode 6 . Multiple propeller electrode designs and ground counter electrodes are able to support propeller rotation and liftoff. Propellers up to 27.8 g and 25.5 cm in diameter were studied with a liftoff voltage range of negative 9.5 kV to 60 kV and rotational speeds up to 80 rot/s. It appears that these are the first EHD devices to liftoff and fly on their own without carrying a power supply 7 . This validates a rotary-based system as a new principle for propulsion with potentially improved stability and control characteristics versus the current EHD devices. Design optimization and scaling seem possible and EHD drone design feasible. Other applications may include EHD motors, fans, or sensors.

Toroidal Counter Electrode for Ionic Propulsion

“…Negative polarity was experimentally demonstrated to allow for overall much larger thrust in air than positive polarity [13][14][15]. Using RIEs we show that slow rotation was produced in pure nitrogen in negative polarity when compared to atmospheric air [14]. This suggests that when compared to atmospheric air, little ionic wind is generated in pure nitrogen, conclusion also confirmed by other experimental work of P. Yan et al [16].…”

“…This suggests that when compared to atmospheric air, little ionic wind is generated in pure nitrogen, conclusion also confirmed by other experimental work of P. Yan et al [16]. In RIE systems, ionic propellers were able to spin and generate conventional axial thrust enough to lift off the high voltage shaft and fly freely for a while without carrying a power supply [13,14]. If enough axial thrust could be generated with rotary ionic engines, rotary ionic drones may be feasible.…”

“…As pin emitters are extending on the trailing edge of the blades, emitted ions will have an induced motion along the electric field projections: Exalong the blade, Ey -perpendicular to the blade and in the propeller rotational plane, and Ezparallel to the propeller axis of rotation. The corresponding electrical forces, Fx, Fy, and Fz, generate thrust and rotational motion of the propellers due to the conservation of linear and angular momentum [14]. Fz leads to linear acceleration of ions between electrodes and to the generation of upwards axial thrust.…”

“…The device was designed with a propeller carrying pin emitter electrodes, concentrical cylindrical counter electrode and worked in negative polarity. Negative polarity was experimentally demonstrated to allow for overall much larger thrust in air than positive polarity [13][14][15]. Using RIEs we show that slow rotation was produced in pure nitrogen in negative polarity when compared to atmospheric air [14].…”

Demonstration of a Remotely Piloted Atmospheric Measurement and Charge Release Platform for Geoengineering

“…Beyond aerosol physics, biological systems and geoengineering, additional motivation is provided by the need to Denotes content that is immediately available upon publication as open access. explore atmospheric consequences of future electric propulsion of aircraft by ion emission and the concept of using ion emission to neutralize the charge on aircraft to prevent the triggering of lightning (Xu et al 2018;Ieta and Chirita 2019). The net electrostatic effects within natural aerosol systems, and their influence on detailed microphysical droplet processes leading to rain, can be investigated with the new experimental capabilities described.…”