Performance analysis of hybrid nanofluid in a heat sink equipped with sharp and streamlined micro pin-fins

• Published in: Powder technology Vol. 355; pp. 552 - 563
• Main Authors: Ambreen, Tehmina, Saleem, Arslan, Ali, Hafiz Muhammad, Shehzad, Sabir A., Park, Cheol Woo
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01-10-2019; Elsevier BV
• Subjects: Aluminum oxide; Brownian motion; Circularity; Computational fluid dynamics; Configurations; Diamonds; Drag; Efficiency; Fin configuration; Fluid flow; Heat; Heat sinks; Heat transfer; Hybrid nanofluid; Micro pin-fin heat sink; Nanofluids; Nanoparticles; Pin fins; Pressure; Pressure drop; Temperature gradients; Thermodynamic efficiency; Thermophoresis; Vorticity; Micro pin-fin heat sink; Fin configuration; Heat transfer; Fluid flow; Hybrid nanofluid
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2019.07.087

This manuscript is aimed at investigating the thermohydraulic characteristics of Al2O3 − Cu/water hybrid nanofluid in a micro pin-fin heat sink by implementing a multiphase Lagrangian–Eulerian approach. In modelling the nanofluid the influence of slip mechanisms i.e. Saffman lift and drag force, Brownian motion, gravity, virtual mass, thermophoresis and pressure gradient-induced force is included. In addition, the fin efficiency of the nanofluid cooled sharp and streamlined fin configurations is probed by analysing diamond, circular and elliptical fins arranged in the staggered assembly. Spherical shaped hybrid nanoparticles of 15 nm are studied for the particle volume fraction of 1%. The performance of heat sinks is evaluated by analysing the quantitative parameters including log mean temperature difference, average (Nuavg) and surface (Nus) Nusselt number. Besides, the flow streamlines, thermal and vorticity contours represent the qualitative depiction of flow and thermal distributions. Results demonstrate that utilising nanofluid optimises Nuavg enhancement to maximum values of 25.14%, 19.65% and 24% for diamond, circular and elliptical fins, respectively. The thermal efficiency of nanofluid is highest across the upstream fins and it diminishes towards the downstream fins. At the highest pressure drop, the fin efficiency of the studied fin configurations is in the order of circular, elliptical and diamond fins.
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•Performance of Al2O3 − Cu/water is investigated in a micro pin fin heat sink.•Hybrid nanofluid is simulated by using a multiphase discrete phase model.•The fin efficiency of diamond, circular and elliptical fins is analysed.•The streamlined fin shapes reduce wake width and promote heat transfer enhancement.•Heat sink with the diamond fins showed maximum Nusselt number enhancement of 25.14%.