Investigation On Structure And Energy Transport Of Nano-fluids

This paper presents a new method for simulating structure and thermal conductivity of nano-fluids by means of the theory of Brown motion and the diffusion-limited colloidal aggregation model (DLCA).Some main characteristics of the nano-fluids, such as stabilization and nanoparticle motion, are introduced. According to the theory of Brown motion, the track of a nanoparticle is simulated. With the theory of the diffusion-limited colloidal aggregation model (DLCA), the processes of particles aggregation and breaking of the clusters are simulated. The fractal theory is applied to analysis of the aggregation structure of nanoparticles.A heat transfer model is developed, and the total energy transported are divided into the static and the dynamic parts. The numeric method is used to calculate the static thermal conductivity, which is compared with the Maxwell formula. The dynamic thermal conductivity is derived from the motion of the nanoparticles. The results of this model agree well with the experiment data. If the nanoparticles aggregation is taken into account, the theoretic predictions would be closer to the experiment data.