Detached eddy simulation of turbulent flow and heat transfer in a two-pass internal cooling duct

Numerical predictions of a hydrodynamic and thermally developed turbulent flow are presented for a stationary duct with square ribs aligned normal to the main flow direction. The rib height to channel hydraulic diameter (e/Dh) is 0.1, the rib pitch to rib height (P/e) is 10 and the calculations have been carried out for a bulk Reynolds number of 20,000. The capability of the detached eddy simulation (DES) version of the 1988 k–ω model has been validated in predicting the turbulent flow field and the heat transfer in a complete two pass channel. Results of mean flow quantities, secondary flows, friction and heat transfer are compared to experiments and large-eddy simulations (LES). It is concluded that in spite of shortcomings in predicting transition correctly at the entrance to the duct, DES surpasses the base capability of the underlying RANS model and predicts flow and heat transfer with good accuracy in a flow which is dominated by separation and reattachment of shear layers, unsteady vortex induced secondary motions, and strong streamline curvature. In all aspects it reproduces the correct physics and shows good quantitative comparisons with LES and experiments while reducing the computational complexity by nearly an order of magnitude.