Very Large Eddy Simulation of turbulent flow and heat transfer for single cylinder and cylindrical pin matrix

Abstract

The study of turbulent flow and heat transfer around a cylinder and cylindrical pin matrix is important for turbine blade cooling. A newly developed VLES method is applied to investigate the unsteady flow and heat transfer mechanisms. DDES and unsteady RANS methods are also used in the simulations for comparisons. Two typical cases are selected, i.e. the flow around a single cylinder, and cylindrical pin matrix of wall-bounded 8 × 8 round pins, with Re = 10000. The results show that the VLES predictions agree well with the experiments for both the flow velocities and heat transfer Nusselt numbers for the two cases, which are even better than the DDES and RANS results. The VLES method gives satisfactory predictions of mean endwall Nusselt number of the complex pin matrix, which is within 15% difference from the experiments. The unsteady three-dimensional vortex characteristics play an important role for the heat transfer, especially in the pin matrix due to complex pin disturbance and wall confinement. Accurate representation of the vortex structures is the key for good heat transfer prediction. The results demonstrate the reliability and accuracy of the present VLES method for complex turbulent convection heat transfer of industrial relevance.