Unsteady flow and heat transfer through triply periodic minimal surfaces

Bruno Miguel Beja Guerra

Key information

Authors:

Bruno Miguel Beja Guerra (Bruno Miguel Beja Guerra)

Supervisors:

Miguel Abreu de Almeida Mendes (Miguel Abreu de Almeida Mendes); José Manuel Da Silva Chaves Ribeiro Pereira (José Manuel Da Silva Chaves Ribeiro Pereira)

Published in

September 23, 2020

Abstract

New advancements in manufacturing methods such as 3D printing, allow the construction and projection of novel metallic foams suitable for the improvement of heat exchangers performance that outperform those typically used. The Triply Periodic Minimal Surfaces (TPMS) are great candidates for the foam structure because they separate the space into two different channels that continually interconnect with a minimum surface area, promoting the minimum use of material with a high heat transfer. The present work deals with the numerical simulations of 3D incompressible flow through periodic porous structures, consisting of cubic cells based on the Schwarz-D (SD) and Schoen-Gyroid (G) topologies with multiple porosities between 60 and 100\%. Simulation results are obtained covering a range of Reynolds numbers from laminar steady flow (Darcy and moderate Forchheimer regime) to laminar unsteady flow (strong Forchheimer regime). Multiple Representative Elementary Volume (REV) simulations in different positions were conducted to validate calculations of macroscopic parameters for porous media models carried out employing a unit periodic cubic cell (single REV). Transition region location to a laminar unsteady regime, as a function of porosity, is obtained. A correlation for the Nusselt number is proposed for the Schoen-Gyroid (G) surface in laminar-steady flow, for a range of porosities and Prandtl numbers. Finally, heat transfer, pumping power, and material efficiency were compared with the usual case of the parallel flat-plate covering the laminar unsteady flow.