Effect of cylindrical ribs location in a fan-shaped cavity on thermo-hydraulic performance of a microchannel heatsink

• Published in: Journal of thermal analysis and calorimetry Vol. 149; no. 11; pp. 5569 - 5583
• Main Authors: Khan, Mohammad Nawaz, Ali, Saqib, Alam, Shahnwaz
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 2024; Springer Nature B.V
• Subjects: Analytical Chemistry; Boundary layers; Chemistry; Chemistry and Materials Science; Fluid flow; Heat sinks; Heat transfer; Holes; Inorganic Chemistry; Measurement Science and Instrumentation; Microchannels; Micromachining; Optimization; Physical Chemistry; Polymer Sciences; Pressure drop; Reynolds number; Numerical simulation; Microchannel heatsink; Cavity; Cylindrical ribs; Thermal performance
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-024-13157-w

The evolution of micromachining technology has ushered in a new era of applications for microchannel heatsinks, particularly in the domain of electronics cooling. This research endeavours to conduct a comprehensive analysis to assess the impact of circular ribs in conjunction with a fan-shaped cavity on the operational efficiency of rectangular microchannel heatsinks. Specifically, seven distinct structural configurations have been meticulously examined, each featuring ribs strategically positioned at various locations: ribs positioned at the front and back (RFB), ribs at the left and right (RLR), ribs at the back and left (RBL), ribs at the front, left, and right (RFLR), ribs at the back, left, and right (RBLR), ribs at the front, back, and left (RFBL), and ribs at the front, back, left, and right (RFBLR), for a range of Reynolds numbers spanning from 100 to 500. The findings are then compared with those obtained from a microchannel with a fan-shaped cavity only (MHFC) and a plain rectangular microchannel heatsink. The optimal diameter for the embedded ribs was determined by comparing the thermal performance of microchannel heatsinks with ribs of varying diameters: 35 µm, 50 µm, 65 µm, and 80 µm. Results indicate that the 50 µm rib diameter achieves the highest thermal performance. A key finding is that ribs act as flow disruptors, causing the flow to split into two streams towards the cavity's arcuate region and thinning the boundary layer. RFBLR showed the highest heat transfer, followed by RFLR, while RFB and RLR had the lowest heat transfer among microchannels with cavities and ribs. RFBLR also had the highest pressure drop, highlighting a trade-off between heat transfer enhancement and pressure drop. Optimizing rib placement is crucial for maximizing heat transfer efficiency at lower pressure drops. Initially, RBLR had the highest performance factor at lower Reynolds numbers, later overtaken by RLR.