A study on particle mechanical dispersion and thermal dispersion in nanofluids

摘要

Particle mechanical dispersion and thermal dispersion in a nanofluid saturated metal foam were investigated analytically using a pore scale conduit model. The dispersion coefficients for both thermal dispersion and particle mechanical dispersion were estimated, using pore scale profiles for velocity and temperature. It has been found that the present analytical expression for the transverse thermal dispersion based on the pore scale analysis closely follows Calmid-Mahajan's empirical correlation. Furthermore, the analysis reveals that the particle mechanical dispersion works either to suppress or to enhance effective diffusion depending on the sign of local phase temperature difference. An interesting analogy was found between the particle mechanical dispersion and thermal dispersion.