Numerical investigation of heat transfer enhancement in a dimpled cooling channel with different angles of the vortex generator

Abstract

This study carried out numerical simulations to investigate the flow and heat transfer characteristics for air flowing in a dimpled cooling channel with a vortex generator. A crescent-shaped protrusion was mounted as a vortex generator on the downstream of the dimple. A direct numerical simulation (DNS) was conducted in a dimpled cooling channel with a Reynolds number of 2800. Seven different cases were considered, including one general dimpled wall and dimpled wall with six different angles inside the vortex generator. For the vortex generator mounted cases, the main design variable is the angle inside the vortex generator, which varies from 0 to 75°. The normalized thermo-performance factors were calculated to estimate the performance of the cooling channel. The normalized thermo-performance factors f/f0, j/j0, and the volume goodness factor decreases as θ increases. The dimpled channel with a vortex generator shows better normalized thermo-performances than the general dimpled channel.