Large eddy simulation of turbulent flow and heat transfer in a turbine disc cavity with impellers

The turbine disc cavity is an important component of a gas turbine, supplying airflow to the turbine blades and the sealing labyrinth. Impellers are installed in the cavity to increase pressure, but their mechanism was unknown in previous studies. Large eddy simulations were used in this study to reveal the effect of the impeller on turbulent flow and heat transfer in a turbine disc cavity. In addition, a nonlinear integral model capable of predicting velocity, pressure, and temperature was developed, which takes into account the heat transfer on the disc walls. This was the first engineering application of nonlinear solution of Ekman layer equations. The large eddy simulation results demonstrated that the vortex development is suppressed by the impeller, and the vortex in the impeller channel flows rapidly to the upstream disc, causing the Nusselt number on the upstream and downstream discs to increase and decrease, respectively. The turbulent heat flux in the central region of the cavity was low due to the destruction of the wall jet. The nonlinear integral model was used to calculate a working condition in <1 s, indicating that it has great potential for engineering applications.