Comparison of the thermal performances of two nanofluids at low temperature in a plate heat exchanger

Abstract

The objective of this study is to compare experimentally the thermal performances of two types of commercial nanofluids. The first is composed of oxides of alumina ((γAl 2 O 3 )) dispersed in water and the second one is aqueous suspensions of nanotubes of carbons (CNTs). The viscosity of the nanofluids is measured as a function of the temperature between 2 and 10°C. An experimental device, containing three thermal buckles controlled in temperature and greatly instrumented permits to study the thermal convective transfers. The evolution of the convective coefficient permits to study the convective thermal transfers. The evolution of the convective coefficient is presented according to the Reynolds number, at low temperature from 0 to 10°C and for the two aforementioned nanofluids. An assessment of the pressure drops in the circuit as well as of the powers of the circulator and outputs is dealt with.

Experimental investigations of the viscosity of nanofluids at low temperatures

“…However such a measurement assumed spherical particles resulting in an average value for the length of the particles [27]. It was reported in [10] that the measured average particle size in the CNT nanofluids is much larger than that of the primary nanoparticles suggesting the nanotubes to form clusters in spite of the use of surfactant.…”

“…Many previous results are obtained for temperature ranging from 20°C to 60°C. So, there are few studies done at low temperatures [10,16].…”

“…Dynamic light scattering measurement was previously performed on the CNT nanofluid investigated in this study [10]. This technique was reported to be effective in indicating the presence of agglomerates [26].…”

“…Actually, viscosity describes the internal resistance of a fluid to flow which is directly related to the pumping power. Maré et al [10] have studied experimentally the thermal-hydraulic performance of Al 2 O 3 and carbon nanotubes (CNT) aqueous based nanofluids in a plat heat exchanger at low temperatures. Their results show that the impact of viscosity and pressure drop is important and has to be taking into account before to use nanofluids.…”

A Review of Heat Transfer Enhancement Using Nano Fluids With Different Base Fluids

“…Compared with traditional slid-liquid suspensions containing millimetre or micrometer sized particles, nanofluids as coolants in the heat exchangers have shown better heat transfer performance because of small size of suspend solid particles. Many research groups experimentally reported that the thermal properties of carbon nanotubes CNT suspensions were much higher than those of other nanoparticles with the small volume fraction [4][5][6]. The addition of CNT improves the thermal conductivity of nanofluids but it can also increase the dynamic viscosity and affect the density and the heat capacity.…”