Experimental determination of nanofluid’s thermal diffusivity under microgravity conditions.
October 2009 – September 2011
“Nanofluids” are suspensions of nanometre sized particles in conventional liquids. Over the last decades, those fluids sparked excitement as well as controversy. The purpose of this interest lies in their potential to improve significantly the performances of heat transfer devices. According to some reports, the presence of a mere few particles remarkably increases the effective thermal conductivity of the fluid. However the experimental data are still relatively few and the results obtained using different experimental techniques are often contradictory. We believe that some of the inconsistencies in the results obtained on ground could be related to disturbance of the experiments by gravity.
The present study aims to investigate the thermal diffusivity of nanofluids under micro-gravity conditions. A transient optical technique is implemented to measure the diffusivity in several samples of different particles concentrations. This technique provides a very precise quantitative measurement. It also allows to visualize the temperature field within the liquid, which may allow to better understand the heat transfer mechanisms in nanofluids.The different gravity steps of the parabolas are used to evaluate the influence of gravity on the quality of the results.
During the QNEM project, we investigated the thermal diffusivity of nanofluids under reduced-gravity conditions during the ESA Fly Ypour Thesis 2011 parabollic flight campaign. A transient optical technique was implemented to measure the diffusivity in several samples of different particles concentrations.