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Impact of Swirl Flow on the Penetration Behaviour and Cooling Performance of a Starter Cooling Film in Modern Lean Operating Combustion Chambers

Impact of Swirl Flow on the Penetration Behaviour and Cooling Performance of a Starter Cooling Film in Modern Lean Operating Combustion Chambers
Tagung:

ASME Turbo Expo 2014
Turbine Technical Conference and Exposition
Paper GT2014-25520

Tagungsort:

Düsseldorf, Germany

Datum:

June 16-20, 2014

Autoren:

Wurm,B.
Schulz,A.
Bauer,H.-J.
Gerendas,M.

Abstract

An experimental and numerical study is presented that deals with the impact of the swirled hot gas main flow on the Penetration behaviour and cooling performance of a starter cooling
film.
Within modern combustion chambers designed for lean combustion the whole fuel/air mixing process is done by the fuel injectors without any additional mixing ports. Typically swirl
stabilization is used within this kind of combustion chambers. The swirl flow interacts in a particular way with near wall cooling flows like starter cooling films which assure a proper wall cooling near the fuel injector. Experiments without combustion show the impact of the swirled main flow on the stability of the starter cooling film. Thermal analyses reveal a reduced cooling performance of the starter film near the Stagnation area of the swirl flow. Laser optical measurement techniques reveal a significant reduced penetration of the starter cooling film close to the stagnation area. Numerical simulations Show the reason for the reduced starter film performance in Areas which cannot be accessed by optical measurement techniques. Based on experimental and numerical data different adaptive hole geometries where tested in combination with heat shield ribs in order to improve the starter film cooling performance. Results show that the combined application of heat shield ribs and adaptive cooling holes stabilize the starter cooling film and  lead to a homogenous cooling performance.