Electrohydrodynamics and its applications: Recent advances and future perspectives

Electrohydrodynamics (EHD) refers to the interaction of electrical forces with fluids, whether liquids or gases. EHD has established itself as an energy-efficient, highly versatile, and effective tool to influence fluids without moving mechanical parts. Therefore, it has found applications in various fields of science and engineering. This review paper categorizes the most notable applications of EHD into five areas, grouping them based on their shared operational principles. The first application area includes electrospinning, electrospraying, and EHD jet printing. The other application areas are EHD-based heat and mass transfer, active airflow control, air filtration or so-called electrostatic precipitators, and EHD-based pumps, thrusters, and blowers. For each application, the fundamental theories are presented, and a summary of the recent advances is discussed. Moreover, a critical analysis of their current limitations and their envisaged future is provided. Finally, the overall application areas status is analyzed using indicators such as technology readiness level (TRL), scalability, and effectiveness compared to similar technologies in their respective fields. The analysis across the five technology areas indicates that electrostatic precipitators are mature and effective, while EHD-based pumps, thrusters, and blowers are in the early stages of development. Electrospinning, electrospraying, and EHD jet printing show promise with moderate technology readiness, while EHD-based heat and mass transfer and EHD-based airflow control fall within a mid-range, reflecting ongoing development. As many reviews on EHD focus on specific applications, the contribution of this review is to draw a comprehensive map of different applications, illustrate their similarities and differences, integrate current knowledge, and highlight areas for further investigation. This interdisciplinary perspective enables researchers to identify various capabilities of EHD and benefit from advances made by other established applications.