The Experimental Study Of Heat Transfer Characteristics Of MWNTs Nanofluids Inside Horizontal Tuhe

Nanofluids are using a certain percentage to solubilize special nanoparticles such asmulti-walled carbon nanotubes to the liquid, and nanoparticless may improve the thermalconductivity and the convection heat reansfer.Nanofluids have a good prospect, but nanofluids as a new heat transfer medium, thepreparation method and process may have the great impact of the fluids characters, such asthe thermophysical properties and the heat transfer character. And the related research workabout the properties of nanofluids is the core of the nanofluids applied research.The main purpose of this paper is using the experimental method to study the convectionheat transfer character of MWNTs in water-based nanofluids in low Reynolds number. Themain works are as follows:1、 Preparation and the properties of multi-walled carbon nanotubes in water-basednanofluids. The Hexadecyl Trimethyl Ammonium Bromide as the dispersant to preparethe nanofluids. Using the spectrophotometer and the settlement observation method tostudy the stability of the nanofluids.2、 Theoretical research about the properties of MWNTs water-based nanofluids,such as thethermal conductivity and viscosity. Analysis the mechanism of the nanoparticles canenhance the thermal conductivity. And tespectively use the Kumar mold and the Einsteinmold to calculated the hermal conductivity and viscosity. The results found that thethermal conductivity of nanofluids had a great increas with increasing of concentration ofnanoparticles; but the viscosity of nanofluids was little changd with the increasing ofconcentration of nanoparticles.3、 Experimental work on convective heat transfer of multi-walled carbon nanotubes-waternanofluids. Design and built the experiment testing system to test the convective heattransfer of nanofluids in horizontal tube. And analyzed the heat balance deviation of thesystem. Through analys the experimental data obtained the conclusion as follows:a) The natural convection of fluid in the tube at turbulent forced convection heattransfer can be ignored;but the natural convection of fluid in the horizontal tube oflow Reynolds number laminar flow can not be ignored.b) Over a range of Reynolds number (flow rate) and the same Grashof number (heatflux), the concentration of nanoparticles in the nanofluids may weakened thecharacter of natural convection.c) Over a range of Grashof number (heat flux) and the same Reynolds number (flowrate), the natural convection character of the fluid enhanced with the conventration ofnanoparticles.d) Correlation of the low Reynolds number mixed convection heat transfer data ofnanofluids. And receive the equation fitting this experiment.