Abstract
Three-dimensional computational fluid dynamics simulations were run to simulate the nanoparticle concentrating in thermophoresis microfluidic devices. Thermophoresis is a phenomenon where particles are driven by a temperature gradient. The microfluidic device utilizes thermophoretic force by applying 10 K temperature difference across the channel. The artificial transverse flow induced by slanted grooves is combined with the thermophoresis to concentrate nanoparticles. Following the experimental research, this study revisited the theory by applying the concept of circulation to evaluate the intensity of the transverse flow. Apart from the original experimental setup with 175 μm groove spacing, 25 μm and 75 μm setups were also simulated as comparison. The comparison shows that the peak circulation has no correlation between different groove spacing. The mass concentration accumulation was analyzed, and smaller spacing resulted in less fluctuation and more effective particle focusing. The averaged mass concentration from the outlet was processed, and in the best scenario, the 25 μm spacing design achieved 68% more concentration than the original 175 μm spacing design from the experiment.
