Mixing between solid and fluid particles during natural convection flow of a nanofluid-filled H-shaped cavity with three center gates using ISPH method

Incompressible smoothed particle hydrodynamics (ISPH) method is modified to simulate the mixing processes between the solid and fluid particles during the natural convection flow in H-shaped cavity filled with nanofluid. The H-shaped cavity has three open gates between the left and right sides. The left wall is kept at a high temperature T-h and the right wall gains a low temperature T-c. Initially, the solid particles are positioned at the left side of the H-shaped cavity with variations on their volumes and thermal conditions. The volume of the solid particles is varying according to the initial variable length L-S. Tracking the mixing processes between the solid and fluid particles at different time instants with measuring the passing solid particles through the three center gates were considered. Effects of the physical parameters, Rayleigh number, volume of solid particles and solid volume fraction on the velocity field, temperature distributions and average Nusselt number are depicted. The performed simulations revealed that most of the solid particles are passing through the upper gate only. The behavior of the mixing processes between solid and fluid particles are depending on the initial volume of the solid particles, initial thermal condition of the solid particles and Rayleigh number. An increase on the solid volume fraction augments the fluid viscosity and consequently the velocity field inside H-shaped cavity and number of penetrated solid particles through the upper gate are decrease. The average Nusselt number is affected by the initial thermal conditions of the solid particles, solid volume fraction and Rayleigh number. From the current investigations, the present ISPH method can handle easily the mixing processes between solid and fluid particles during natural convection inside complex cavity. (C) 2020 Elsevier Ltd. All rights reserved.