Heat transfer and flow analyses of microchannel heat sink with twisted blade-like fins

To enhance heat transfer coefficient, decrease pressure penalty, and improve wall temperature uniformity, a twisted blade-like fin with low-drag airfoil section is proposed in this study. The flow and heat transfer performances of microchannels with the fins are numerically investigated at Re = 50–700. Results show that the novel fins improve the heat transfer (Nu/Nu₀) significantly with a small pressure penalty (f/f₀), and thus show an excellent comprehensive thermal performance (TP). The ranges of Nu/Nu₀, f/f₀ and TP are 1.16–4.76, 1.51–2.36, and 1.01–3.58, respectively. The TP of TAMCHS reaches 3.58, exhibiting an increase of 46.7, 37.7, 22.6, and 16.6% compared to four models in previous study. The reduced pressure penalty is attributed to the streamlined configuration, and the improved heat transfer coefficient is attributed to the normalwise secondary flow stimulated by the twisted fins, which enhances heat transfer in the upper portion of the channel. Compared to a smooth microchannel heat sink (SMCHS), the major advantages lie in the significant reduction of sidewall temperatures and notable improvement in temperature uniformity on the top and bottom walls. The average and maximum wall temperature are reduced by 48.1 and 49.0 °C at most, respectively, and the greatest decline of wall temperature gradient is 55.0 °C.