Electrical characteristics of high-speed water nanodroplets under different generation conditions
Journal
International Journal of Plasma Environmental Science and Technology
Journal Volume
20
Journal Issue
1
Start Page
e01005
ISSN
18818692
Date Issued
2026-04-01
Author(s)
Abstract
The charging behavior of microdroplets has been extensively investigated. However, experimental studies focusing on nanoscale droplets remain limited. Building upon the charge-generation mechanism established in our previous work, this study investigates how nanodroplet generation conditions affect the charging behavior of nanodroplets impinging on a copper plate. To assess the influence of nanodroplet generation conditions, vessel pressure (3−5 atm), water heater power (250−400 W), and nozzle temperature (160−200 °C) were systematically varied using a lab-made high-speed nanodroplet generator over a nozzle-to-plate distance of 1−20 mm. For all conditions, both the electric current and the electrostatic elimination rate exhibited a pronounced maximum at 1 mm (the closest position to the nozzle exit), and they rapidly decayed to zero with increasing distance. Typically, under operating conditions of a nozzle temperature of 170 °C, a water heater power of 280 W, and a vessel pressure of 5 atm, the electric current and electrostatic elimination rate reached −35.9 nA and −7115 V s−1, respectively, at a distance of 1 mm. Increasing vessel pressure enhanced flow velocity and impact intensity, resulting in a higher induced electric current. Increasing the water heater power increased the evaporation input, producing more nanodroplets in the flow and enhancing charging responses. In contrast, higher nozzle temperatures intensified the superheating of the water vapor–air mixture and delayed nanodroplet condensation, producing smaller droplets and reducing charge transport. Furthermore, normalized data indicate that the reduced initial droplet size promoted rapid evaporation and easier dissipation when nanodroplets traveled downstream. These findings clarify which generation conditions and parameters govern nanodroplet charging behavior and downstream evolution.
Subjects
collision
condensation
Nanodroplet
supersonic flow
triboelectrification
Publisher
Institute of Electrostatics
Type
journal article