Application Cases

Experiment Name: Experimental Study on Acoustoelastic Flow of Non-Newtonian Fluids in Microchannels

Research Direction: Complex Flow Behavior of Fluids in Acoustic Microfluidics

Experimental Content: Investigation of the influence of fluid rheological properties on acoustoelastic flow.

Test Equipment: Signal generator, ATA-308 power amplifier, particle velocimetry system, etc.

Experimental Process:

Figure: Experimental system diagram

Aqueous solutions of polyethylene oxide (PEO) with different concentrations (50–1000 ppm) were prepared. Their shear viscosity and elastic modulus were measured at 25°C using a stress-controlled rheometer to verify their Boger fluid characteristics (constant viscosity, significant elasticity). A sinusoidal wave of 2.0 ± 0.6 kHz generated by a signal generator was amplified using the ATA-308 power amplifier to drive sharp-edge vibrations within the microchannel, exciting the acoustoelastic flow field. Fluorescent polystyrene microspheres were used to trace the flow field, and a microscale particle image velocimetry (μPIV) system was employed to capture velocity vector distributions. Mixing hysteresis at low flow rates (Q < 600 μL/min) and flow pattern degradation at high flow rates (Q > 1000 μL/min) were analyzed.

Experimental Results:

Figure: Experimental results 1

Figure: Experimental results 2

Low-concentration PEO (50 ppm) exhibited an acoustic-dominated positive mode (GI > 0) under the acoustic field, while high-concentration PEO (1000 ppm) showed a negative mode (GI < 0) with a reduced disturbance range due to enhanced elastic effects. The competitive mechanism between elasticity and inertia was quantified using a Wi-Re phase diagram. Spatiotemporal disturbance attenuation was analyzed using short-time Fourier transform (STFT), revealing the suppression effect of the shear layer reattachment zone on molecular migration in acoustoelastic flow (disturbance intensity reduced by 30–50%). This study provides a theoretical basis for the micromanipulation of complex fluids.

Recommended Power Amplifier: ATA-308C

Figure: ATA-308C power amplifier specifications and parameters