Heat transfer augmentation in a radial curved microchannel

Abstract

Rapid advancement toward miniaturization has emerged with confront for superior heat dissipation techniques. Of all the available cooling systems, microchannel-based cooling systems stand out to provide better cooling performance through superior heat removal abilities. In the present study, the cooling performance and hydraulic flow characteristics of a radial curved microchannel with three curvature ratios were numerically investigated and compared with a radial straight microchannel. Unlike the conventional straight microchannels, curved channels possess better fluid mixing as a result of the centrifugal force caused due to curvature. This phenomenon has a significant effect on heat transfer and fluid flow characteristics. Work on radial curved microchannels has been scarce and there is a lot of potential to augment the heat transfer with lower pumping power particularly with a central inlet. A three-dimensional conjugate heat transfer analysis was carried out for three radial curved microchannels and a radial straight microchannel using the ANSYS Fluent commercial software with the Reynolds number range of 125–275. The results showed a Nusselt number increment of 36.38% for radial curved microchannels when compared to the radial straight microchannel. Further, the lowest average wall temperature was noted for the radial curved microchannel with a curvature ratio of 0.17 which was 15.63 °C lower when compared to that in a radial straight microchannel for the same Reynolds number. Contours of velocity and temperature are presented at various locations along the stream to aid the results. The overall performance of all three radial curved microchannels was found to be higher than that of the radial straight microchannel in the Reynolds number range considered, out of which the maximum performance factor of 1.245 was obtained for the radial curved microchannel with a curvature ratio of 0.17 as compared to the radial straight microchannel.

Influence of secondary flow channels on heat transfer and fluid flow characteristics in curved microchannel

“…Figure 1a,b represents the top view and isometric view respectively, of conventional curved microchannel (CCMC) and the CMCSF having radius of curvature (ROC) equal to 15 mm. With reference to the previous study 28 that involves the analysis of three radiuses of curvatures, the model with ROC equal to 15 mm showed better results of Nusselt number and average wall temperature. Hence, ROC 15 mm was chosen for analysis.…”

“…The authors 28 earlier validated the numerical procedure with experimental work carried out by Lee et al 6 that were based on copper‐made microchannel heat sink with cooling fluid as deionized water. The numerical results were relatively closer with experimental results as shown in Figure 3.…”

“…It is noted that the significant studies of improved heat transfer in microchannels neglect to study the effects of secondary flow passages in curved microchannels that can be accommodated on to heat sink having circular shape with central inlet and circumferential radial outlet. 28 In this paper, forced convection study of curved microchannels with secondary flow channels with laminar flow is proposed. Numerical simulations were carried out using commercial software ANSYS Fluent.…”

“…Separately, it has also been observed that oblique fins can be used to create secondary flows to enhance the performance of microchannels because of disruption of boundary layers, furthering the effect of curved walls. It is noted that the significant studies of improved heat transfer in microchannels neglect to study the effects of secondary flow passages in curved microchannels that can be accommodated on to heat sink having circular shape with central inlet and circumferential radial outlet 28 . In this paper, forced convection study of curved microchannels with secondary flow channels with laminar flow is proposed.…”