Li near corre lation between ther mal conductivity e nhancement and flu id adsorption in water nan ofluids at different temperatures

This is known that addition of nanoparticles can increase ther mal conductivity of the base fluid [۱]. Betwee n various factors, the layering behavior of the fluid molecules on the nanoparticles surface has a de terminant r ole on increasing the nanofluid thermal conduc tivity. Temperature, can affect the layering of fluid molecu les around a nanoparti cle as well as the shape and size of nanoparticle, densit y, intermole cular and nanoparticle -fluid mole cules intera ctions [۲].Due t o the solid-like orderin g of the fluid around n anoparticle, the local de nsity of the base fluid c lose the pa rticle surface is usually greater than the bulk fluid. The nu mber of adsorbed molecules on the nanoparticles surface can be showed by excess adsorption. Excess adso rption aroun d a spherical particle can be calculated by the following equation [۳]:(...)WHERE is T is excess adsorption P(r)is the local density and r is the nanoparticle -fluid molecule distance. Due to the solid-like ordering, the thermal conductivity coefficient of the adsorbed fluid is greater than the base fluid and fewer than the metallic nanoparticles . Therefore, with increasing the excess adsorption, the ther mal conducti vity will enhance.

کلیدواژه ها:

Nano fluid ، Therm al Conductivity ، Nanoparticle.