Fine-tuning width and aspect ratio of an improved microchannel heat sink for energy-efficient thermal management

Highlights: • Parametric study of a 4-compartment MCHS with multiple coolant inlets and outlets. • New parameter (ω) for substrate temperature gradient proposed. • Wide, moderate aspect ratio channels better than narrow, high aspect ratio channels. • Nu, dimensionless pumping power & total thermal resistance correlations developed. - Abstract: Computational experiments were performed to study the influence of microchannel width and aspect ratio on performance of a four-compartment, microchannel heat sink with dedicated coolant inlet and outlet for each compartment. Wide range of coolant velocity (0.25–2 m/s) & aspect ratio (2–10) and a reasonable range of microchannel width (100–200 μm) have been simulated. The appropriate microchannel width and aspect ratio were found to be 200 μm and 6, as evidenced from lowest total thermal resistance and lowest non-uniformity of substrate temperature at comparable power consumption among different microchannel widths and aspect ratios simulated. A new parameter 'ω' has been proposed for representation of substrate temperature gradient considering maximum, average and minimum substrate temperatures. Correlations have been developed for prediction of dimensionless pumping power, Nusselt number and dimensionless total thermal resistance. Hence, the four compartment heat sink with 200 μm wide channels of aspect ratio 6 can be used for energy-efficient thermal management.