PhD defense - F. Wlassow

Unsteady aerothermal analysis of a turbine stage with hot streaks migration: application to the mastery of blade performances

Delivered by Ecole Centrale de Lyon - MEGA
Speciality: Mechanics


May 7, 2012 - CERFACS and Ecole Centrale de Lyon

In order to increase the thermodynamic efficiency of gas turbine engines, the high-pressure turbine inlet temperature has been continually increased up to reach levels of the order of magnitude of the vanes and blades melting temperatures. The ability of predicting the flow through the turbine (especially the temperature) is a key point for the design of gas turbines, especially for the uncooled ones. However, this is challenging because of the complex environment that interacts with the turbine (hot-streak migration, technological details, fluid/solid thermal coupling . . .). The aim of this work is to develop a strategy based on CFD in order to predict aerothermal fields in a high-pressure turbine as well as an analysis allowing to quantify the impact of the environment on the turbine performances. To achieve these goals, the elsA code has been used to perform unsteady simulation of a turbine stage, taking into account technological details (squealer tip, external cooling thanks to vane trailing edge cooling and rotor hub and shroud cooling cavities, fillets) and conjugate heat transfers. An analysis of the local entropy production rate was also used to compare the performances resulting from different modeling of the turbine (taking into account or not one particular technological detail) and to localize the origin of these discrepancies. The results show that the tip height and the external cooling have the greatest impact on the turbine performances. The rotor blade temperature is mainly affected by the flow coming from the combustion chamber, the external cooling and the fluid / solid thermal coupling. This work is the first step towards the realization of integrated simulations allowing to improve the accuracy of design.

T. Arts	Von Karman Institute for Fluid Dynamics (Belgium)	Referee
R. Denos	European Commission (Belgium)	Referee
P. Ferrand	CNRS	Member
J. Piquet	Ecole Centrale de Nantes	Member
G. Leroy	Turbomeca Bordes	Member
N. Gourdain	CERFACS CFD	Co advisor
G. Ngo Boum	Centrale Innovation Nantes	Co advisor
F. Leboeuf	Ecole Centrale de Lyon	Advisor

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