Localized heating effects of liquid based on SAW streaming

When a liquid droplet is placed on a surface acoustic wave (SAW) propagation surface, a longitudinal wave is radiated into the liquid and the liquid begins to stream, jet, and atomize. This phenomenon is known as SAW streaming. We describe experimental results concerning the temperature of a thin liquid layer and liquid droplet during SAW generation. The results reveal that the temperature of the liquid is a function of the SAW amplitude, which is determined by the applied voltage. This means that the liquid temperature can be controlled by the applied voltage. Rapid rise and fall times are realized by the SAW. The influence of viscosity with respect to temperature is also discussed. Due to viscous damping of the radiated longitudinal wave, temperature of a high-viscosity liquid is higher than that of at low-viscosity liquid at the same applied voltage. We conclude that a novel micro-liquid heating system can be realized using the SAW device.