Numerical investigation of various twisted tapes enhancing a circular microchannel heat sink performance

Abstract

The continuous power increase and miniaturization of modern electronics require increasingly effective thermal management systems. The thermo-hydraulic performance of water-cooled L×L square-base silicon microchannel heat sinks is investigated by a conjugate heat transfer and computational fluid dynamics model over the Reynolds number range 100 to 500. Water at a constant inlet temperature of 298 K runs through 33 parallel tubes, extracting heat from the bottom wall that has a 100 W/cm2 constant heat flux input. Hydro-thermal performance-enhancing tape inserts are numerically tested featuring (i) radial gaps between the tape and the tube, (ii) tape twist with axial pitch distances of ∞, L/2, or L/4, (iii) zero, one, or two 90-degree angular steps between consecutive tape segments, (iv) alternating clockwise and anti-clockwise consecutive twisted tape segments, and combinations of these features. The radial gaps produce both a hydraulic and a thermal performance loss. All combinations of tape twist, angular steps, and twist direction reversal produced better thermal performance gains to hydraulic loss trade-offs than the baseline microchannel configuration with no tape. The microchannel heat sinks with four L/4 alternating pitch consecutive helical tape segments provided the lowest bottom wall average temperature, 16.13 K below that with not tape, at the same Reynolds number of 500. This predicted temperature drop is a significant achievement towards conditioning electronic components so they may be longer-lasting, use less energy, and have a reduced environmental impact.