Investigation of wavy microchannel ability on electronic devices cooling with the case study of choosing the most efficient microchannel pattern.

A numerical study was conducted to investigate the ability of wavy microchannels to damp the temperature fluctuations generates in electronic devices. Five wavy patterns are considered with the amplitude and wavelength in the ranges of 62.5 to 250 μm and 1250 to 5000 μm, respectively to study the effect of governing phenomena of flow within wavy patterns on thermal-hydraulic performance. The flow regime is laminar and the Reynolds number is in the range of 300 to 900, and a relatively high heat flux of 80 W/cm is applied to the microchannels substrate. Also, variable flux condition is studied for heat fluxes of 80, 120, 160, 200, and 240 W/cm and for the most efficient wavy and straight microchannels. Results showed that the geometries with larger amplitude to wavelength ratio have a lower radius of curvature and larger Dean number, and as a result of transverse flow (secondary flow) amplification, they have enhanced heat transfer. Also, by comparing the ratio of the transverse velocity components to the axial component, it was found that by decreasing the radius of curvature and increasing the Dean number, transverse velocity increases, which intensifies the heat transfer between the wall and the fluid. The appraisement of the performance evaluation criterion (PEC) illustrates that the wavy case with an amplitude of 250 μm and wavelength of 2500 μm is the best geometry from the thermal-hydraulic point of view in the studied range. Finally, with variable flux condition, the wavy microchannel has responded well to the temperature increase and has created a much more uniform surface temperature compared to straight pattern. The proposed wavy pattern ensures that there are no hotspots which could damage the electronic chip. Presented wavy patterns can be used in heat sinks heat transfer enhancement to allow the chip to run in higher heat fluxes.