Abstract
Following the industrial trend of increasingly integrative and combined design and analysis of the combustor-turbine interaction (CTI) interface, the European Commission FP7 project FACTOR (Full Aerothermal Combustor-Turbine interactiOns Research) was launched several years ago. Since then project partners contributed to the turbomachinery field by publishing results from numerous numerical studies as well as experimental investigations. The project ended in late 2017 after successful completion of the main experimental test campaign involving rotating turbine rig hardware, which was assembled, integrated and operated on DLR’s recently erected, closed-loop turbine test facility ‘NG-Turb’ in Göttingen, Germany.
The 1.5 stage FACTOR turbine rig features a non-reacting combustor simulator to create a non-uniform swirl and temperature distribution of a lean-burn-type inlet flow. This combustor simulator is rotatable against the turbine NGV. During the 2017 FACTOR experimental campaign, two specific clocking positions were tested and a complete set of data is available.
Based on the already published experimental results from planar probe traverses in core HP turbine stations, this paper discusses combustor-turbine-interaction effects and highlights the influence of combustor-NGV clocking on the flow structures in different planes as well as the turbine performance. For the first time, the FACTOR rig data is evaluated in direct comparison with CFD simulations concerning clocking effects.
As an initial step towards seamless CFD simulations without critical engine component interfaces, a combustor-turbine calculation was recently published by DLR involving the FACTOR combustor simulator and the first NGV in an uncooled configuration. Any recent work by several project partners, including DLR, did not succeed in satisfactorily matching the obtained experimental results, despite tremendous efforts concerning resolution and modeling using LES. That documents the complexity of the task involving highly non-uniform flow fields and the need for further investigations. For the current work, the available computational resources are hence used to evaluate both clocking positions from the experimental campaign rather than applying costly modeling like LES to a single configuration.
By following a two-fold modeling approach, this paper gives more insight into the complex numerical simulation of the FACTOR combustor-turbine interface. The complete 1.5 stage turbine is simulated using steady RANS CFD, including the accurate resolution of coolant feed channels and purge flow cavity volume geometries. First, the turbine simulation is initialized with as-measured experimental turbine inlet plane 2D profiles. Secondly, for comparison, an integral combustor-turbine RANS calculation is configured, connecting both components and meshes at turbine inlet in a single setup. This ultimately highlights and quantifies the impact of potentially inaccurate preceding component modeling on downstream component simulation: an inherent problem that will become more and more relevant to the community as the trend towards integrally coupled multi-component simulations or even whole engine modeling continues.
On the Influence of Combustor-Turbine-Interface Modeling and Clocking Effects in Flow Simulations of a Cooled High-Pressure Turbine Test Rig
Category
Technical Paper Publication
Description
Submission ID: 1726
ASME Paper Number: GT2020-14970
Authors
Alexander Krumme German Aerospace Center DLR
Clemens Buske German Aerospace Center DLR
Simon Gövert German Aerospace Center DLR
Marc Tegeler German Aerospace Center DLR
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