A dielectric barrier discharge ion source increases thrust and efficiency of electroaerodynamic propulsion

Abstract

Electroaerodynamic (EAD) propulsion, which produces a thrust force by electrostatic means, has been proposed as a method of electric airplane propulsion which is solid-state and nearly silent and produces no combustion emissions. Previous work demonstrated that EAD is capable of sustaining flight of heavier-than-air airplanes. The most successful EAD propulsion devices have thus far used a direct current (DC) corona discharge to produce ions and the same DC field to accelerate them. However, these corona discharge EAD devices are subject to a performance trade-off where increasing thrust reduces efficiency (thrust-to-power ratio). This is a key barrier to practical adoption. Here, we show that by using a dielectric barrier discharge (DBD) instead of a corona discharge to produce ions, while still using a DC field to accelerate them, higher thrust and thrust-to-power can be achieved. We identify operating regimes for this thruster, optimize the electrical characteristics of the DBD ion source, and find that the thrust-to-power can reach up to 20 N/kW at a thrust of 50 mN/m and up to 10 N/kW at 150 mN/m—in both cases, approximately twice that of the equivalent corona discharge devices. With lower power draw for the same thrust, DBD enhanced EAD propulsion devices could increase the endurance of EAD airplanes and begin to enable the design of practically useful solid-state aircraft.

Performance of decoupled electroaerodynamic thrusters

“…A model for the performance (i.e., current, thrust, and power draw) of decoupled EAD thrusters has not been determined before although the authors' previous work found qualitative differences to corona discharge thrusters. 7 The results presented here support a quantitative characterization of decoupled thrusters with a DBD ion source, which captures the effect of both DC acceleration parameters such as DC voltage and electrode gap spacing and AC ionization parameters such as AC voltage, AC frequency, and DBD electrode separation. In particular, we provide a model for the interaction between the ionization stage and the acceleration stage-this interaction was not relevant in corona discharge thrusters, in which the ionization cannot be independently varied from the acceleration.…”

“…We showed that an implementation of a decoupled thruster that used an alternating current (AC) dielectric barrier discharge (DBD) ion source could provide a significantly higher thrust for the same power consumption than the equivalent corona discharge thruster. 7 This results in a higher thrust-to-power ratio (a relevant measure of the static efficiency), suggesting that decoupled thrusters could increase the endurance and mission capability of solid-state aircraft. Alternative decoupled architectures have also been proposed; for example, Orrie `re et al 8 recently studied a decoupled EAD device with a nanosecond repetitively pulsed discharge ion source.…”

“…The electric current produced by a corona discharge is below the space-charge limited current, which represents the maximum DC current for a given geometry and applied DC voltage. The authors' previous investigation, 7 which demonstrated that decoupled thrusters could improve the performance of EAD thrusters, suggested that in a decoupled thruster, the current-voltage relationship would not be given by Eq. ( 2).…”

Recent Progress in Artificial Muscles for Interactive Soft Robotics

“…The accelerated ions by the high electric fields can transfer their momentums to the gaseous mediums during the acceleration process, leading to the EAD flows. [91][92][93][94] For soft robotic applications, deformable electrode materials with high conformability and excellent electrical stabilities under high voltages will be required to produce stable charge injections in the EHD and EAD devices, which are still quite challenging.…”

“…The EAD process is a promising alternative for the propelling systems in aerial vehicles with its simple and lightweight architecture, silent operation, and no requirement of moving components. [91][92][93][97][98][99] Xu et al has recently demonstrated an electrical solid-state propelling system with the EAD process, [94] which was consisted of an asymmetric electrode pair (one small electrode for ionization of the air and one large electrode for ion collection, as shown in Figure 2d). The EAD engine provided a thrust-to-power ratio of 5 N kW -1 , comparable to the conventional jet engine (3 N kW -1 ), which could be used to achieve a 40-50 m flight within 8-9 s on a fixed-wing aeroplane (Figure 2e).…”