Numerical simulation on flow regulation and heat transfer characteristics of embedded adaptive pin-fin microchannel heat sinks under non-uniform heat sources

This work proposes an adaptive pin-fin microchannel cooling configuration that employs the thermally responsive deformation of hydrogel pin-fins to manage the transient and spatially uneven thermal loads generated during chip operation. Temperature-driven volumetric changes in the hydrogel structures enable continuous adjustments of coolant passage geometry, allowing the system to redistribute flow locally and achieve self-regulating thermal control. A dynamic-mesh numerical approach is developed to characterize pin-fin deformation under high heat-flux conditions and to evaluate its impact on flow behavior and heat dissipation. Compared with non-adaptive microchannel heat sink (N-MCHS), the adaptive design (A-MCHS) demonstrates distinctly improved coolant routing and enhanced thermal performance. Under a single-hotspot condition with a heat flux of 100 W/cm 2 , the A-MCHS lowers the peak hotspot temperature by 7.5 K and reduces the pressure drop by 44.4%, while requiring only 2.26 mW of pumping power. The corresponding Nusselt numbers (Nu) for A-MCHS and N-MCHS are 7.36 and 5.68, respectively, confirming the superior heat transfer capability and low energy demand of the adaptive configuration. The system also maintains effective temperature suppression when multiple hotspots are present. Additionally, as the Reynolds number (Re) increases, the A-MCHS consistently achieves lower hotspot temperatures and reduced thermal non-uniformity relative to the N-MCHS, highlighting its stable thermal regulation behavior. Overall, the proposed adaptive microchannel structure provides a promising route toward efficient, low-power, and self-adjusting cooling solutions for chips operating under dynamically evolving heat flux conditions.