Coupling mechanism of kinetic and thermal impacts of Rayleigh surface acoustic waves on the microdroplet

Mehmood, Mubbashar, Nawaz Chaudhary, Tariq, Burnside, Stephen, Khan, Umar F., Fu, Yong Qing and Chen, Baixin (2022) Coupling mechanism of kinetic and thermal impacts of Rayleigh surface acoustic waves on the microdroplet. Experimental Thermal and Fluid Science, 133. p. 110580. ISSN 0894-1777

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An experimental study has been conducted to investigate the coupling mechanism between thermal and kinetic impacts of surface acoustic waves (SAW) using a water droplet (25 µl) on the zinc oxide (ZnO) thin-film piezoelectric substrate fabricated on an aluminium plate. The temperature is measured by an infrared (IR) thermal camera, and fluid streaming was detected by particles image velocimetry (PIV). The input power ranges from 0.096 W to 3.2 W resulting in a temperature rise and streaming velocity in the droplet up to 55 °C and 24.6 mm/s, respectively. It is found that the thermal impact is insignificant at lower input power (<0.50 W); however, this becomes dominant when the input power is>2.0 W. The study also found that heat inside the droplet is distributed via streaming from the heat source. The heat is distributed from the heat source where SAW power penetrates to the droplet. Another key finding of this investigation revealed that when the input power is>0.50 W, inverse heat transfer from the droplet to the substrate is observed due to the increase in fluid temperatures.

Item Type: Article
Additional Information: Funding information: We acknowledge the financial support from the UK Engineering and Physical Sciences Research Council (EPSRC) grants EP/P018998/1, and Special Interests Group of Acoustofluidics under the EPSRC-funded UK Fluidic Network (EP/N032861/1). The authors are thankful to the University of Northumbria Newcastle upon Tyne, UK for providing the experimental setup for this work. The authors are thankful to Heriot-Watt University, Edinburgh, UK for their support.
Uncontrolled Keywords: Rayleigh SAW, Radiated heat transfer, Energy absorbed, ZnO thin film
Subjects: H800 Chemical, Process and Energy Engineering
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Elena Carlaw
Date Deposited: 04 Jan 2022 11:13
Last Modified: 21 Dec 2022 08:00

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