Numerical investigation on the influence of particle deposition on nanofluid turbulent flow and heat transfer characteristics

Abstract

Based on the two-body collision model, a particle collision, deposition and peeling model is established to investigated the influence of nanoparticle deposition process on TiO2 -water nanofluid turbulent flow and heat transfer characteristics in a horizontal circular tube by compiling, linking and executing a program with the Euler-Lagrange multiphase model in Ansys Fluent 19.1. Compared with four different multiphase flow models, this model has a better consistency with the pressure drop of experimental data. And it is applied to study the influence of particle deposition on the flow field and heat transfer. The flow characteristics is analysed from micro-flow perspective to reveal the nanofluid heat transfer enhancement mechanism. Result shows that the nanoparticle deposition layer grows as clusters during flow process, the nanofluid velocity boundary layer becomes thinning, it is easier to deposit at the entrance and the amount can reach more than 7 times of that minimum near the outlet. The velocity difference value between phases is larger as much as 1.23642 m/s, which directly enhances the momentum exchange and energy exchange between phases and wall. That plays a main role of heat transfer enhancement.