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

Abstract

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 peiformed 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 inteiface. 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.

The Influence of Combustor Swirl on Pressure Losses and the Propagation of Coolant Flows at the Large Scale Turbine Rig (LSTR): Experimental and Numerical Investigation

“…Cha et al [8] have investigated the migration of the burner core using a passive CO 2 tracer, which was fed through the fuel injectors into the combustor. They determined a pronounced concentration profile at the turbine inlet, resembling a hot streak location.…”

Combustor Dilution Hole Placement and Its Effect on the Turbine Inlet Flowfield

“…The level of swirl normally present in an aeroengine RQL combustor was presumed to be negligible relative to the effect of high-momentum flux dilution injection. The study by Cha et al [15] for a similar RQL geometry also indicated little effect of upstream swirl on dilution jet trajectory.…”

“…Another potential issue from performing separate simulations is the absence of the vane's impact in the combustor simulation; this is especially true for combustors with dilution jets positioned near the turbine inlet. Cha et al [15] showed through experimental and computational studies that the nozzle guide vane's (NGV) potential field has an effect on the upstream combustor flow. Cha et al found that the NGV's impact occurs well before the combustor-turbine interaction plane where many combustor-only studies end.…”

Volumetric PIV measurement for capturing the port flow characteristics within annular gas turbine combustors

“…This is then delivered to the vertically mounted test section through a bell-mouthed inlet and honeycomb flow straightener. The test facility is able to operate a 1.5 stage axial flow compressor to deliver pre-diffuser flow structures that are representative of the engine environment (Cha et al 2012). For these tests, however, the compressor rotor was replaced with a pre-swirl vane row, designed to replicate the approach flow angle provided to the outlet guide vane row by the rotor.…”