Investigation of Heat Transfer and Fluid Flow Characteristics in Microchannel Heat Sinks Designed for Cooling of High-Power Electronics in Nigerian Telecommunications Infrastructure

The thermal management of high-power electronics in telecommunications infrastructure deployed across Nigeria's expanding mobile network represents a significant engineering challenge, as elevated ambient temperatures combined with intense component heat fluxes demand highly effective cooling solutions that minimise energy consumption and footprint. This study investigates the heat transfer and fluid flow characteristics of single-phase water-cooled microchannel heat sinks designed for the cooling of base station power amplifier modules operating in Nigerian climatic conditions. A parametric computational study was conducted using ANSYS Fluent with the conjugate heat transfer model for five microchannel cross-sectional geometries, including rectangular, trapezoidal, triangular, circular, and semicircular profiles, over a Reynolds number range of 200 to 1,500. Channel dimensions were selected to be compatible with direct bonding to standard power amplifier packages. Nusselt number, Poiseuille number, overall thermal resistance, and pressure drop were evaluated for each geometry and flow condition. Results showed that the rectangular channel geometry with an aspect ratio of 4:1 provided the lowest overall thermal resistance of 0.08 degrees Celsius per Watt at a Reynolds number of 1,200, while incurring a pressure drop penalty 22 percent higher than the circular geometry. Optimisation using the thermal performance factor metric identified the trapezoidal channel as the best overall performer, offering a 14 percent improvement in thermal performance factor over the rectangular geometry. Experimental validation using a fabricated aluminium microchannel test module confirmed computational predictions within 9 percent for thermal resistance measurements. Keywords: microchannel heat sink, electronics cooling, heat transfer, computational fluid dynamics, telecommunications infrastructure.