Numerical analysis of microchannel heat sink performance using delta vortex generator

The design of unique microsinks arises from the desire to provide efficient cooling at low pressure drop for a more compact miniaturized electronic equipment. Three-dimensional numerical investigations of heat transfer and fluid flow have been carried out with delta vortex generator (DVG) structures in the rectangular microchannel. A pair of delta vortex generators (DVGs) are placed symmetrically about the horizontal mid plane in rectangular microchannels. Performance variances are assessed on the basis of the average Nusselt number (Nu), friction factor (f), and thermal performance (TP) along with the thermal resistance (R-T) and hydraulic resistance (R-H) for the Reynolds number in the range of 93 to 746. The parametric variation has been carried out by altering geometric parameters such as the angle of DVGs with centerline (theta), the number of pair of DVGs (n), the length of DVGs (l), the distance of DVGs from the centerline (B), the position of DVGs from the inlet for first pair (L-1), and the distance between the vortex generators (S). The objective is kept to maximize the TP, to minimize the value of thermal resistance, and to decrease the increase in the hydraulic resistance for the same geometrical variation. The highest thermal performance equal to 1.256 has been achieved with the combination of theta, n, l, B, S, and L-1 equal to 45 degrees, 3, 0.6 mm, 0.1 mm, 4.5 mm, and 5.334 mm, respectively. For the same geometrical parameters, a minimum thermal resistance equal to 0.98 K/W and a hydraulic resistance equal to 3.234 kPa-min/ml have been attained at Re about 745.66. By minimizing the thermal and hydraulic resistance of the microchannel with DVGs, it becomes possible that heat can be more effectively transferred across the interface and the desired cooling can be achieved with less power input. The implementation of DVGs enhances intermixing through the generation of longitudinal and transverse vortices, leading to a more evenly distributed temperature across the channel. This enhancement in the heat transfer reduces the thermal resistance. Additionally, the vortices generated by DVGs modify the velocity profile, thereby decreasing the pressure drop and the hydraulic resistance. The specific impact of longitudinal vortices on the enhancement of the heat transfer through adjustments in geometric parameters is thoroughly elucidated.