Numerical Modeling of Convective Heat Transfer for Turbulent Flow in “Bubbler” Cooling Channels

Abstract

In the present study, a numerical model was developed to investigate the heat transfer effect of single-phase turbulent flow in a “bubbler” geometry, typical for cooling channels in the high-pressure die-casting process. A steady-state $k - \omega$ model with fine near-wall resolution was compared with established empirical relations developed by Gnielinski et al. for pressure drop and Nusselt numbers in turbulent flow in smooth pipes and annular ducts. The empirical relations matched well with the simulations. At the “tip” of the bubblers, impingement of the flow to the channel wall was found to intensify heat transfer locally. Increasing the ratio between inner and outer pipe diameters caused the flow to separate, increasing the pressure drop at the bend and the intensification of heat transfer.