A 2D and 3D numerical study of heat transfer modulation using pulsatile flow in minichannel heatsinks

The increasing energy demands for data centres require more efficient cooling systems and technologies to improve the thermal management and enable waste heat recovery. This paper investigates the use of pulsatile flow to increase heat transfer enhancement in liquid cooled minichannel heat sinks with the use of CFD. ANSYS Fluent 2025 R1 was used for 2D and 3D laminar simulations of the heat sink under laminar flow conditions, with steady Reynolds numbers ranging from 18.5 to 92.1, frequencies from 0 to 3 Hz (corresponding to Womersley numbers from 0 to 4.49), and pulsating to steady velocity ratios from 0% to 880%. Results showed that pulsatile flow generally enhances heat transfer when compared to steady flow, although only for pulsating to steady velocity values exceeding a threshold of 100%. The maximum heat transfer enhancement of 89% was observed for a Womersley number of 4.49 (3 Hz), steady Reynolds number of 64.5, and a pulsating Reynolds number of 570.8. Compared to the experimental results, both the 2D and 3D CFD models have an approximate mean absolute percentage error (MAPE) of 9-16% when compared to the correlation generated by Kennedy & Persoons (2026). Improved mixing and boundary layer disruption were identified as the main mechanisms for the enhancement in heat transfer. As expected, pulsating flow also increased the pressure drop and pumping power requirements, which are the trade-offs between performance and heat transfer enhancement.