ICAS-GT: Fluid flow and heat transfer within the rotating internal cooling air system of gas turbines

• Forschungsstelle: EU FRP
• Projektnummer: 97.0380
• Projekttitel Englisch: ICAS-GT: Fluid flow and heat transfer within the rotating internal cooling air system of gas turbines

Schlüsselwörter (Englisch)

Secondary air system; air transfer systems; rotating cavities; heat transfer; turbulence; rim seals; hot gas ingestion; computational fluid dynamics; hybrid mesh

Alternative Projektnummern (Englisch)

EU project number: BE97-4021

Forschungsprogramme (Englisch)

EU-programme: 4. Frame Research Programme - 2.1 Industrial and materials technologies

Kurzbeschreibung (Englisch)

See abstract

Partner und Internationale Organisationen (Englisch)

SNECMA (F), BMW-RR (D), MTU (D), TURBOMECA (F),
Volvo Aero Corporation (S), Fiat Avio (I), AGT (UK), ITP (E), ABB (CH), Sussex University (UK), Bath University (UK), Aachen University (D), Karlsruhe University (D)

Abstract (Englisch)

This project is concerned with the problems of heat transfer and fluid flow within gas turbine internal cooling air systems, with the aim of improving the design of the latter for both advanced aircraft and electrical power generation gas turbines. Participants in the proposal are ten major European engine manufacturers and four Universities specializing in this type of work.
As task leader ALSTOM (Switzerland) AG is mainly involved in task 1. The objective of this task is to experimentally investigate different (ALSTOM relevant) rim seal configurations by the University of Aachen and to compare the results with CFD calculations. From the experiments correlations were created, that will directly go into the Gas Turbine Secondary Air Flow design tool of ALSTOM (Switzerland) AG. The comparison of CFD results and data was used for the evaluation of the CFD program and is also being implemented into the design process.
The task of ALSTOM (Switzerland) AG in the ICAS-GT project mainly covered numerical work, for both static and rotating configurations. During this report period a state of the art calculation procedure was developed in close cooperation with Turbomeca and Volvo. Based on the drawings for the rim seal testrig at the University of Aachen, a 3D numerical mesh was generated using a hybrid-meshing tool. This mesh was distributed to the task partners in order to have a common platform for the CFD-work. Turbomeca calculated the unsteady 2D flow in the hot gas path of the 1.5 stage turbine. The contribution of VOLVO was a 3D and unsteady calculation of the entire test turbine.
ALSTOM's part of the task was the conduction of 3D rim seal and cavity flow calculations for a wide range of operating conditions. The CFD-work of the different partners was found to be in good agreement. However, the comparison to the experimental data revealed an unexpected phenomenon, which was not predicted by the computations. The time-dependant pressure measurements from the University of Aachen showed pressure fluctuations in and below the rim-seal, which are decoupled from the rotor frequency. It is expected that the combination of these results with additional CFD modeling will close this open issue in the frame of the planned ICAS GT2-project.
In addition to the CFD simulation a semi - empirical method has been developed for a fast estimate of ingestion into the rim seal cavity which is very useful for 1D codes used typically in concept phases and parametric studies. The method is based on the extensive measurements carried out at the Aachen university as part of the ICAS-GT project.
The combination of numerical and experimental work within the frame of the ICAS-GT task 1 project provided a comprehensive database, which will be incorporated into the design-tools of ALSTOM (Switzerland) AG. As a benefit of the program, the turbine rim seals of ALSTOM's gas turbine engines can be improved in terms of sealing efficiency and prevention from hot gas ingestion.

Datenbankreferenzen (Englisch)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 97.0380