Experimental study on thermal performance of water-based nano-PCM emulsion flow in multichannel heat sinks with parallel and divergent rectangular mini-channels

• Published in: International journal of heat and mass transfer Vol. 146; p. 118861
• Main Authors: Ho, C.J., Hsu, Shao-Teng, Jang, Jer-Huan, Hosseini, Seyyede Fatemeh, Yan, Wei-Mon
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2020; Elsevier BV
• Subjects: Channels; Flow velocity; Fluid dynamics; Fluid flow; Heat flux; Heat sinks; Mini-channel heat sink; Nano-PCM emulsion; Nanoparticles; Nusselt number; Parallel and divergent channels; Phase change materials; Pressure drop; Reynolds number; Thermal performance; Viscosity; Wall temperature; Working fluids; Mini-channel heat sink; Nano-PCM emulsion; Parallel and divergent channels; Thermal performance
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2019.118861

•Thermal performance of MCHSs with parallel and divergent minichannel heat sinks is studied.•The divergent mini-channel increases the wall temperature as compared with the parallel one.•The heat transfer is improved by adding the PCM nanoparticles to the base fluid. In this work, an experimental study is arranged to investigate the cooling efficacies of water-based nano-PCM emulsion flow in the multi-channel heat sinks with parallel and divergent rectangular mini-channels. N-eicosane particles with size of 130 nm are considered as the phase change material (PCM) nanoparticles. Two multi-channel heat sinks with eight parallel and divergent mini-channels are fabricated. The divergent channel has a divergent angle of 2.06°. The effects of different parameters including volumetric flow rate of working fluid (60 cm3/min <Q̇ < 600 cm3/min), heat flux (3.2 W/cm2 <qh′′ < 4.8 W/cm2), Reynolds number (100 < Re < 1000), and mass fraction of PCM nanoparticles (0% <ωPCM < 10%) on the dimensionless wall temperature, the Nusselt number, the cost of performance (COP), and the pressure drop are investigated. The experimental results show that the nano-PCM emulsion can improve heat transfer in both parallel and divergent mini-channel heat sinks as compared with the pure water. At Rebf = 965 and qh′′ = 3.21 W/cm2, the average Nusselt number in the parallel mini-channel heat sink improves about 15.2% by adding the PCM nanoparticles with mass fraction of 10% to the base fluid. This enhancement is up to 13.8% in the divergent mini-channel heat sink at Rebf = 295 and qh′′ = 3.21 W/cm2. Moreover, the divergent mini-channel heat sinks provide a higher Nusselt number along with lower pressure drop as compared with the parallel ones. Accordingly, the value of COP increases by diverging the mini-channel.