Session: 12-08-02: Computational Heat Transfer and Applications II

Paper Number: 165692

Numerical Study of Interconnected Straight-Converging Microchannel Heat Sink for
Enhanced Thermal-Hydraulic Performance 

The rapid increase in power densities and operating temperatures, driven by continuous miniaturization and the relentless pursuit of integration in microelectronic devices, has become a concern for thermal engineers due to the limited heat dissipation capacity of traditional cooling techniques. Microchannel heat sinks (MCHSs) have gained significant attention for cooling the intensely heat-generated microelectronic devices due to their higher surface area to volume ratio and the incredibly compact form factor. However, gradually increasing thermal-hydraulic boundary layers along the flow direction in conventional MCHS results in high temperature non-uniformity, high thermal stress, and increased pumping power, which have compelled researchers to explore advanced cooling strategies. Aiming at this issue, in this paper, a novel hybrid single-phase parallel-flow microchannel heat sink consisting of an array of the combination of straight and converging channels with interconnectors is proposed to take advantage of improving thermal performance by the boundary layer disruption and reinitialization with moderate pumping power penalty. Asymmetric pressure distribution along streamwise direction in adjacent straight-converging channels create secondary flows between them through interconnectors, segmenting the flow region into multiple zones. A comparative numerical analysis of thermal and hydraulic performance was performed for interconnectors of different widths placed transversely at various locations, with a constant heat flux of 20 W/cm² on the bottom of the copper substrate having a dimension of 28 mm length, 7 mm width, and 0.5 mm thickness. Numerical simulations were conducted using ANSYS FLUENT for a coolant volumetric flow rate ranging from 100 to 600 mL/min under laminar flow conditions, with water as the working fluid entering the flow domain at 293K. Numerical models were validated with the conventional parallel-flow microchannel heat sink consisting of an array of straight channels. Two parallel-flow microchannel heat sinks—one with straight channels and the other with converging channels—were considered as the base cases. The overall performance of the proposed heat sinks was evaluated by analyzing the overall Nusselt number (Nu), friction factor (f), temperature uniformity, pumping power, and overall thermal resistance. The numerical results from the developed model manifested that our proposed hybrid MCHS outperforms the conventional designs with lower base temperature, higher temperature uniformity, and minimal pumping power requirement by enhancing the flow mixing, suppressing the thermal boundary layer, and exploiting the differential pressures between converging and straight channels. An extensive study was conducted on the placement and width of the interconnectors due to their significant impact on the overall performance of heat sinks, which can be utilized for optimizing the compact design of MCHS with interconnectors.

Presenting Author: Akin Chakma University of Mississippi

Presenting Author Biography: Akin Chakma is a graduate research and teaching assistant in the Mechanical Engineering department at the University of Mississippi. Before joining the University of Mississippi, he obtained his B.Sc. in Mechanical Engineering from Bangladesh University of Engineering and Technology in 2022. His research interests center around leveraging Computational Fluid Dynamics (CFD), Electro-Magnetic Performance, and Thermo-Hydraulic Performance Analysis techniques to develop novel heat exchange devices and cooling strategies focusing on improving the thermal management performance of EV powertrains and microelectronic devices.

Authors:

Akin Chakma University of Mississippi
Amitav Tikadar University of Mississippi