Performance improvements of microchannel heat sink using Koch fractal structure and nanofluids

Abstract

With the rapid development of microelectronics technology, the heat flux density in the micro-component system is very high. Therefore, the design of new and efficient cooling and heat dissipation devices has become an urgent problem to be solved. We use the Koch fractal structure and nanofluid to create a new type of microchannel heat sink. In this paper, a single-phase method is used to numerically study the flow and heat transfer properties of TiO2-water nanofluids in microchannels and optimize the structure with Koch fractal baffles. The effects of various volume fractions of nanofluids and baffles with varying structures on the inlet and exit pressure drop, flow resistance coefficient, substrate temperature, and Nusselt number (Nu) in the microchannel are investigated. In the Reynolds number (Re) range of 100–1000, the Nu of nanofluid increases with the increase of Re and the Nu increases from 18.19 to 60.41, which increases by 3.32 times, and the flow resistance of nanofluid falls by 1.79 times. Nanofluids' improved heat transfer factors are not all larger than one. The critical point is Re = 439, indicating that the combined heat transfer performance of nanofluids is superior to that of deionized water within the Re range of 100–439.