CFD-Informed Spacer Grid Models in CTF: Heat Transfer Enhancement and Form Pressure Losses

This report presents the current status of the pressure loss coefficient and heat transfer enhancement models derived for CTF from computational fluid dynamics (CFD) data. This is an effort to improve the modeling capabilities of CTF using results from a higher-fidelity code such as STAR-CCM+. The following four phenomena are the current scope of CFD-informed spacer grid models for CTF: (1) grid directed lateral cross-flow effects; (2) grid-induced turbulent-mixing effects; (3) grid-induced heat transfer enhancement downstream of the grid; and (4) the detailed pressure-loss effects caused by the spacer grid. This document covers phenomena (3) and (4) and how they are captured using CFD data. Please refer to CASL-U-2015-0020-000 for a discussion on phenomena (1) and (2).