Experimental and Numerical Investigation of Single-Phase Heat Transfer and Pressure Drop in a Rectangular Mini-Channel Heat Sink

Liquid-cooled mini-channel heat sinks can remove heat from compact electronic footprints, but comparisons among experiments, analytical correlations, and CFD can be distorted when external tubing/header losses are treated as channel losses or when one-sided heating is reduced using an arbitrary heated area. This study examines a copper heat sink containing fifteen parallel rectangular mini-channels over sixteen operating conditions combining four electrical heat inputs (6.25–100 W) and four volumetric flow rates (0.15–0.45 LPM). The work combines rectangular-duct analysis, heat-loss-corrected experiments, uncertainty propagation, and three-dimensional conjugate CFD, with explicit distinction among gauge-span, device, header, and channel-core pressure losses. The revised thermal reduction replaces the previous fixed effective sidewall height with a fin-efficiency treatment appropriate to base heating, and the thermal-resistance definition is made consistent with the heat-transfer coefficient. The measured coolant temperature rise spans 0.17–9.06 K over a Reynolds-number range of 34–104, while the hydraulic analysis shows why the complete gauge-span pressure drop cannot be interpreted as a channel friction loss. CFD is used to interpret local flow redistribution and temperature fields using clearly specified pressure-extraction locations and mesh-sensitivity limits. The resulting procedure provides a traceable basis for separating measured, modeled, and inferred quantities when comparing thermal performance with the device-only hydraulic penalty of a low-Reynolds-number mini-channel heat sink.