Numerical prediction on the drag force and heat transfer of non-spherical particles in supercritical water

Abstract

Particle-resolved numerical simulations are conducted on both conventional fluid (CF) and supercritical water (SCW) passing over a set of Platonic particles. Platonic particles are considered because they are typical non-spherical particles that hold common features and their sphericity (ϕ) changes gradually with the particle face number. By investigating drag coefficient (Cd) and average Nusselt number (Nu) obtained at different Re, the unique characteristic of heat and mass transfer of SCW is highlighted whose physical parameters can change with temperature (T) and pressure (P) sharply around the critical points. Influences of Re and ϕ on Cd and Nu are also discussed. Numerical results show that, for both CF and SCW, Cd increases with the decrease of ϕ and Re but the opposite changing trend takes place on Nu. It is also found that Cd and Nu of these non-spherical particles in CF can fit the previous correlations well but not the case for SCW. Therefore, novel correlations of Cd and Nu for non-spherical particles in SCW are established which can be good tools to understand the basic knowledge of SCW (Working conditions: P = 23 MPa, 647 K ≤ T ≤ 657 K, 0.671≤ϕ≤0.939 and 10 ≤ Re ≤ 200.)