Towards Unsteady Simulation of Combustor-Turbine Interaction Using an Integrated Approach

Abstract

In this paper a CFD solver with the ability of dealing with both reacting and compressible flows is developed, so that an integrated simulation of the whole system “combustor and turbine” can be performed. To its validation, the combustor-turbine interaction in a jet engine consisting of a Rolls-Royce combustor together with the first high-pressure turbine stage NGV (Nozzle-Guide-Vane) is studied. The unstructured CFD solver follows a pressure-based approach, using a PISO algorithm (Pressure Implicit with Splitting of Operator) recently extended for compressible flows. In order to allow acoustic waves to leave the computational domain, nonreflecting boundary conditions based on the NSCBC method (Navier-Stokes Characteristic Boundary Conditions) have been implemented. The numerical methods have been coupled with the Flamelet Generated Manifold combustion model (FGM) extended for compressible flows. After successfully verifying the NSCBC implementation, various numerical results describing the combustor-turbine interactions of the jet engine are analyzed and discussed in terms of temperature and total pressure fields with and without NGV. It could be shown that the influence of the NGV on the combustor flow is relatively limited. Differences in the combustor flow field are mainly due to spatial and temporal averaging used for the simulation without NGV to calculate the pressure field at combustor outlet. These numerical results demonstrate the ability of the developed numerical model in its steady computation mode to well capture the evolving flow properties in both combustor and turbine components.