Heat transfer enhancement and optimization for a novel secondary connected wavy fractal MCHS

Abstract For high-energy and electronic devices to operate steadily, microchannel heat sinks (MCHSs) must dissipate heat quickly. This feature improves device reliability, which is essential for demanding applications in micro-electro-mechanical systems. This work explores the thermal and hydraulic characteristics of secondary connected fractal heat sink (SC-FHS) and secondary connected wavy FHS (SC-WFHS) devices manufactured by metallic 3D printing using both numerical and experimental approaches. MCHS inserts are fabricated by laser powder bed fusion technology from AlSi10Mg metal powder. Casing for the inserts is printed using a stereolithography technique from Model V3 photosensitive resin. Only single-phase flow is considered with water as the coolant. The range of the volumetric flow rate ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mover> <mml:mi>v</mml:mi> <mml:mo>˙</mml:mo> </mml:mover> </mml:mrow> </mml:mrow> </mml:math> ) is from 100 to 300 ml min −1 . Further, a numerical parametric study is conducted by varying the wavy amplitude ( A ) of the SC-WFHS device. The thermal performance of the SC-WFHS ( A = 0.5 mm) device is found to be superior compared to the SC-FHS ( A = 0 mm). A maximum enhancement of 53% is found in the average Nusselt number ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mover> <mml:mrow> <mml:mi>N</mml:mi> <mml:mi>u</mml:mi> </mml:mrow> <mml:mo accent="true">―</mml:mo> </mml:mover> </mml:mrow> </mml:math> ) of the SC-WFHS ( A = 0.5 mm) device at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mover> <mml:mi>v</mml:mi> <mml:mo>˙</mml:mo> </mml:mover> </mml:mrow> </mml:mrow> </mml:math> = 300 ml min −1 compared to the SC-FHS ( A = 0 mm). Better flow circulation with increased velocity in the secondary connected (SC) channel of the SC-WFHS improves the temperature distribution by mitigating the hotspots compared to the SC-FHS device. The SC-WFHS ( A = 0.5 mm) device operating at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mover> <mml:mi>v</mml:mi> <mml:mo>˙</mml:mo> </mml:mover> </mml:mrow> </mml:mrow> </mml:math> = 300 ml min −1 is found to be optimal for thermo-hydraulic performance according to the Vlse Kriterijumska Optimizacija I Kompromisno Resenje (VIKOR) optimization method.