Ricerc@Sapienza

The present research aims to to study the turbulence modulation in an particle-laden annular pipe flow, via Direct Numerical Simulation (DNS). The alteration of the heat exchange through the cylinder shells is also studied. The inter-phase momentum coupling is enforced with the recent Exact-Regularised Point-Particle method (ERPP). The research focuses on the particle agglomeration close to the wall, the so called turbophoresis. The correlation of this phenomenon to the friction wall drag and fluid thermal modification is explored. For this purpose the turbulent intensities, the fluid mean temperature and velocity profiles, the turbulent and viscous shear stresses and the mean particle concentration will be examined. The effect of wall curvature will be also explored. We plan to study different combinations of mass ratios and particle diameters, while the background turbulence is fixed. The Prandtl and the friction Reynolds numbers are Pr=0.7 and Re*=200, respectively. The particle to fluid density ratio is 180. The radial aspect ratio is Ri/Ro=0.25, where Ri and Ro are the internal and external wall radius, respectively. The equations to be solved are the incompressible Navier-Stokes equations, the Fourier equation and the particle momentum equation. The differential equations are implemented over a parallel code ( MPI ). The code will run in the clusters "Menrva", of the Department Aerospace and Mechanical Engineering ( DIMA ) of La Sapienza, and "Galileo" of the Cineca facility.