Experimental investigation of heat transfer and pressure drop in a minichannel heat sink using Al2O3 and TiO2–water nanofluids

Abstract

Nanofluids are known as a new generation of coolants. These fluids have attracted more attention in cooling applications, like electrical, optical, and solar systems recently, because of their unique rheological and thermal properties. In the present study, to evaluate the thermal behavior of the nanofluids, Al 2 O 3 and TiO 2 nanoparticles with the size of 20 nm were completely dispersed in distilled water and circulated in a minichannel heat sink. The heat sink consists of 10 minichannels that have designed to cool thermoelectric generators. The results showed that by only dispersion of 0.5 vol% Al 2 O 3 nanoparticles a 9.30% heat transfer enhancement observed. It was also obtained that the TiO 2-water sample showed a 4.56% heat transfer enhancement. The highest efficiency was obtained by utilizing the Al 2 O 3-water nanofluid. This was attributed to the higher thermal conductivity of Al 2 O 3 compared to TiO 2. Using both nanofluids resulted in higher pressure drop compared to the based fluid. At the Reynolds number of 1000, the pressure drop for Al 2 O 3 and TiO 2 nanofluids increased as 3.33% and 3.88%, respectively. The increased pressure drop was attributed to higher density and viscosity of nanofluids. The classical theories are not available to justify the remarkable heat transfer enhancement obtained by adding a negligible amount of mentioned nanoparticles. It seems that new mechanisms such as the random motion of nanoparticles and generated microconvections by nanoparticle motion in the base fluid are responsible for considerable heat transfer enhancement.

Thermal conductivity, viscosity and heat transfer process in nanofluids: A critical review

“…Thermal properties of the working fluid play an essential role in the heat transfer rate of a thermal system. The working fluid commonly has weak thermal properties, therefore the improvements of these properties increase the efficiency of thermal devices, reduce costs, and results in more compact and miniaturized devices [20]. The properties of some of the base fluids that are utilized commonly in various investigations are presented in Table 4 [187,[215][216][217][218].…”

“…The miniaturization of the channels, using the fins, or utilizing nanofluids are some common passive methods [11,[14][15][16][17]. In the last decades, due to the developments of miniaturized devices, such as computer electron-ic components, the old techniques of cooling became inadequate [15,[18][19][20]. Besides, the evolutions in technology have created an urgent demand for new and efficient cooling methods to maintain the device temperatures below the critical area.…”

Performance and application analysis of ANFIS artificial intelligence for pressure prediction of nanofluid convective flow in a heated pipe

“…According to the literature pertaining to NFs, although the heat transfer possessed the potential of enhancement by the NFs, the more pressure is lost by the nanoparticles fraction. Moghanlou et al 6 conducted a systematic experimental-based work on the nanofluid heat transfer in a mini channel. They also considered the pressure drop in NFs.…”

Effect of graphite die geometry on energy consumption during spark plasma sintering of zirconium diboride

“…Owing to the concerns about the environmental issues and lack of fossil fuel resources, it is needed to enhance the performance of the working devices [1,2]. The energy saving may be obtained by introducing new operational methods [3] or increasing the efficiency of the devices using passive or active enhancement methods [4][5][6]. Manufacturing technology consumes a high percentage of energy, therefore investment in this area may result in remarkable energy saving.…”