Swirl flow in microchannels: patterned slip walls enhance heat transport

Abstract

Microchannel heat sinks (MCHS) are widely used for thermal management in high-power electronics due to their ability to dissipate large heat fluxes with minimal coolant consumption. While numerous strategies - such as geometric modifications, surface disruptions, and enhanced coolant formulations - have been explored to improve heat transfer, many of these approaches increase hydraulic resistance and pumping power requirements. Recent studies have shown that slip/no-slip wall patterns can enhance flow rates and convective heat removal without additional energy input, and that patterned microstructures can induce secondary swirling motions known to promote mixing and heat transfer. Motivated by these findings, we investigate a slip/no-slip pattern specifically designed to generate swirl flow inside a straight microchannel. Building upon prior work on passive chaotic advection and boundary-condition engineering, we assess the hydrodynamic and thermal performance of this patterned configuration under conditions relevant to laminar microchannel cooling. Our results demonstrate that appropriately arranged slip/no-slip regions can induce swirl without geometric perturbations or increased pumping power, ultimately improving heat transfer efficiency at fixed volumetric flow rate. This study highlights the potential of boundary-condition patterning as a simple, energy-neutral strategy for enhancing the performance of microfluidic heat-transfer devices.

Figures (11)

• Figure 1: Square duct representation with a slip/no-slip pattern in the channel walls.
• Figure 2: Heat flow evacuated at different flow rate regimes varying the stripe angle $\theta$ at the channel walls (triangles for $\theta=25^{\circ}$, circles for $\theta=45^{\circ}$, and squares for $\theta=65^{\circ}$). Thinner stripes case (largest number of stripes, $n=200$) are the blue ones, and the thicker stripes case (fewer number of stripes, $n=25$) are the red ones. For reference, we plot the homogeneous no-slip case (open diamonds) and the homogeneous full slip case (filled diamonds). The dashed lines between the points serve as a guide for the eye.
• Figure 3: Heat flow $Q$ normalized by $Q_{\text{no slip}}$ (horizontal dashed gray line) evacuated at different flow rate regimes $\dot{V}$ for the different slip-pattern cases $n=25, 50, 100, 200$ and $\theta=45^{\circ}$. The heat flow in the full slip case is shown with gray diamonds.
• Figure 4: Comparison between the temperature cross-sectional profile ($z=L$) for the no slip and the optimal slip-pattern microchannel ($\theta=45^{\circ}$$n=200$).
• Figure 5: Velocity streamlines and temperature maps at different cross-sectional areas along the channel for the optimal slip pattern case ($\theta=45^{\circ}$$n=200$).