Numerical study of turbulent heat transfer and flow characteristics of hotflow over a sudden-expansion with base mass injection

This study presents the numerical calculations of the fluid flow and turbul ent heat transfer characteristics of hot flow over a sudden-expansion with cold air base mass injection. The turbulent governing equations are solved by a control-volume-based finite-difference method with power-law scheme, t he well known k-epsilon model, and its associate wall function to describe the turbulent behavior. The velocity and pressure terms of momentum equatio ns are solved by the SIMPLE (Semi-Implicid Method for Pressure-Linked Equat ion) method. In this study non uniform staggered grids are used. The parame ters interested include the inlet Reynolds number (Re), inlet temperature ( T-o), and the injection flow rate (Q). The numerical results show that the reattachment lengths are reasonably pre dieted with a maximum discrepancy w ithin 9.1%. It also shows that the base mass injection suppresses the horiz ontal velocity and turbulence intensity. In these high temperature heat tra nsfer characteristics, the heat transfer coefficient increased with increas ing inlet temperature and inlet Reynolds number, but decreased with increas ing injection flow rate of the cooling air.