Development and performance characterization of an ultrasonic vibration induced electric spray microthruster for pocketqube applications

This paper presents the development of a new micropropulsion system for PocketQube (PQ) platforms, addressing the challenges of limited spatial volume and electrical power availability. The system utilizes a vibrating mesh atomizer (VMA) driven by a piezoelectric actuator to atomize working fluids into fine droplets, generating thrust through their ejection. Two working fluids—water and 50 wt% aqueous ethylene glycol (EG)—were tested to evaluate the system’s performance. Impedance analysis revealed that water exhibited higher impedance values, while 50 wt% EG showed a more stable response due to its higher viscosity. High-speed imaging confirmed that the spray produced by water was more diffuse, while 50 wt% EG resulted in more uniform atomization. The thrust measurements demonstrated a maximum thrust of 121.16 µN for water at 116 kHz and 116.07 µN for 50 wt% EG at 118 kHz. Notably, the system achieved a high thrust-to-power ratio, with 168.28 µN/W for water and 161.21 µN/W for 50 wt% EG, and a thrust-to-power-mass ratio of 2.16 µN/W·g. This high thrust-to-power-mass ratio is critical for PQ applications, where both power and spatial constraints are significant limitations. These results highlight the potential of ultrasonic atomization for efficient and scalable PQ propulsion, with areas for future improvement in specific impulse and operational efficiency.