Experimental and Numerical Investigation of Combustor-Turbine Interaction Using an Isothermal, Nonreacting Tracer

Understanding the interaction between the combustor and turbine subsystems of a gas turbine engine is believed to be key in developing focused strategies for improving turbine performance. Past studies have approached the problem starting with an existing turbine rig with inlet conditions provided by “representative” hardware which attempts to mimic some key flow features exiting the combustor. In this paper, experiments are performed which center around complete engine hardware of the combustor, including engine geometry turbine nozzle guide vanes (NGVs) to solely represent the upstream impact of the complete turbine. This domain ensures that the traditional interface between combustor and turbine is sufficiently encompassed and not compromised by obfuscating or limiting effects due to approximating combustor hardware. The full-annular experimental measurements include all components of the velocity and pressure fields at various planar sections perpendicular to the primary flow direction. These include detailed, two-dimensional measurements both upstream and downstream of the NGVs. The combustor is a classic rich-burn design. Passive scalar (CO2) tracing measurements are performed to gain insight into the flow responsible for the temperature fields in the coupled system, including the impact of the NGVs on the upstream flow at the conventional combustor-turbine interface. CFD simulations are used to develop a complete picture of the combustor-turbine interface and the coupling between the two subsystems. The complementary experimental and simulation datasets are together intended to provide a benchmark for future, more traditional turbine rig tests and turbine CFD simulations where inlet conditions are at the exit plane of the combustor.