(383d) Acoustothermal Heating in an Open Microfluidic Channel

Surface acoustic wave (SAW), when interacts with liquid, causes significant heating (called acoustothermal heating) due to conversion of acoustic energy into internal energy. Here, we have theoretically demonstrated SAW driven acoustothermal heating in an open microfluidic channel filled with Newtonian fluids. We have used multiple timescale-based perturbation approach to separate the fast and slow timescales associated with oscillatory and mean flow and temperature fields. As the first order components are oscillatory, their time-averaging is zero and hence the acoustothermal heating arising due to SAW can be denoted by quantifying the second order temperature only. We have carried out parametric studies to see the effect of SAW power, microchannel aspect ratio and frequency on acoustothermal heating. We have also compared the results with closed microfluidic channel.