Computational Study on Fully Coupled Combustor–Turbine Interactions

Abstract

Combustor–turbine interactions are investigated by modeling the unsteady flowfields inside a realistic combustor and high-pressure turbine configuration from the Energy Efficient Engine program. We perform three-dimensional unsteady simulations to capture a liquid-spray fuel/air combustion and relative motions between the combustor and turbine using the Open National Combustion Code. To understand combustor–turbine interactions, we perform both sequential single-component simulations (step 1: [Formula: see text] stator of turbine; step 2: the turbine imposing the time-averaged flow solution from step 1 as the inflow) and a fully coupled combustor–turbine simulation (step 3) at two operating conditions: the simulated sea-level takeoff (SLTO) condition ([Formula: see text]) and a more realistic SLTO ([Formula: see text]). Although the mean flowfields inside the combustor predicted by steps 1 and 3 are similar, there is a noticeable difference in the hot-streak distributions at the first-stage stator. In addition, the shock wave appears at the first-stage stator only for steps 2 and 3 for the low-pressure condition and for step 3 for the high-pressure condition. The calculated turbine efficiencies from step 2 and step 3 differ by about 7%. From both conditions, it is consistently observed that fully coupling the combustor and turbine enhances temporal oscillations of the turbine efficiency through the temperature fluctuations generated in the combustor.