Comparison of BMM (Brownian movement models) with Experimental Data for Prediction of Thermal Conductivity Enhancement in Nanofluids

Suspensions produced by dispersing nanoparticles into a base fluids, have nowadays become a serious concern. As they can play an important role for thermal purposes, it is expected to be utilized in many fields such as airplanes, cars, micro machines in MEMS, micro reactors etc. For this, there have been strong demands for more efficient heat transfer fluids in many industries.The innovative idea of ‘nanofluids’, i.e. nanoparticles suspension in liquid media; was developed by Dr. Choi of Argonne National Laboratory in 1995 [1]. Compared with millimeter or micrometersized particle suspensions, nanofluids possess better long term stability, much higher surface area and more effective rheological properties. Traditional theories extensively explain the thermal conductivity enhancement of usual slurries and suspensions. The basic model of Maxwell was extended by some researchers who included the effect of shape, particle interactions, and particle distribution. In general, Maxwell’s method works well for a low thermal conductivity ratio (~10) between the solid and the fluid.