Prediction on drag force and heat transfer of spheroids in supercritical water: A PR-DNS study

Abstract

To carry out numerical simulations on the particle-laden supercritical water (SCW), one needs to know drag coefficient (Cd) and average Nusselt number (Nu) of the solid particles in SCW according to the high temperature and pressure conditions. This study conducts particle-resolved direct numerical simulations (PR-DNS) to obtain Cd and Nu of spheroids in SCW whose physical properties significantly change with temperature and pressure. A series of case studies are designed to match different working conditions. Effects of variable physical property parameters of SCW on Cd and Nu of spheroids are discussed. Numerical results show that the variable viscosity of SCW plays a more important role in influencing on Cd of spheroids in SCW rather than density, thermal conductivity or specific heat capacity. All these four parameters could affect Nu and the largest effect comes from the specific heat capacity. New correlations of Cd and Nu for spheroids in SCW are proposed according to the numerical results which can facilitate the phase coupling in multi-phase flow modellings of SCW.