Experimental study on forced convection heat dissipation efficacy of concurrent flow of water/Al2O3 nanofluid through a mini- and micro-channel stacked double-layer heat sink

Abstract

In this study the method of experimental measurement is used to explore the force convection heat transfer gain and pressure drop of using pure water or alumina-water nanofluid to through a mini- and micro-channel stacked double-layer heat sink and a single-layer micro-channel heat sink at different flow ratio The mini- and micro-channel stacked double-layer heat sink is composed of a single-layer micro-channel heat sink stacked with a millimeter-channel heat sink Both the micro-channel heat sink and the millimeter-channel heat sink are formed by oxygen-free copper With a fixed total width (14 4mm) the micro-channel heat sink has 24 rectangular channels with a length of 50mm a width of 0 3mm and a height of 0 9mm and the converted hydraulic diameter is 0 45mm The mini-channel heat sink has 12 rectangular channels with a length of 50mm a width of 0 8mm and a height of 2 4mm and the converted hydraulic diameter is 1 2mm The experimental conditions are fixed total flow The fixed total flow is 346 0 692 0 and 1038 0 which is defined by pure water physics property and micro-channel size at Reynolds numbers 500 1000 and 1500 The total flow is passed through the mini- and micro-channel stacked double-layer heat sink in different proportions The flow ratio is 0 5 1 0 1 33 1 5 2 0 2 5 3 56 The inlet temperature is fixed at 30 The total heat taken away by the fluid is 265W which is converted into a heat flux of 36 8 From the experimental results it can be known that the mini- and micro-channel stacked double-layer heat sink can indeed greatly reduce the pressure drop which is 93 49% lower than that of the single-layer micro-channel heat sink In terms of heat transfer gain the use of pure water/ nanofluid has a maximum gain of 76 47% In addition this experiment also found that the nanofluid has a higher heat capacity and thermal diffusivity which will cause the wall temperature to unable be suppressed This reason will also be discussed in this article

Date of Award	2020
Original language	English
Supervisor	Ching-Jenq Ho (Supervisor)