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Abstract

Effusion cooling is frequently used to lower the thermal constraints of combustion chambers in aeronautical gas turbines. It consists of injecting a cold air ow through submillimetric holes drilled in the liners. The resolution of the ow in the near-wall regions in 3-D combustion chamber calculations is out of reach in terms of computational cost due to the presence of small scales. Models were proposed to reduce the computational cost in previous works. An adiabatic homogeneous model, to represent the aerodynamics around the plate, based on the resolved Large Eddy Simulation of an infinite perforated plate was proposed. It was later extended to model the aerothermal behavior of the ow, based on resolved RANS calculations. The objectives of this work are to evaluate the homogeneous aerothermal predictions regarding the flux repartition and to propose a model to account for effusion cooling in industrial computations of the flow around the perforated plate. Large Eddy Simulations coupled with a thermal solver have been performed in order to get insight of the flow organization and the heat flux repartition around the plate. Two configurations at a representative aero engine operating point are studied: two channels separated by 12 converging rows with either perforations oriented in the main flow direction or with an angle of deviation. The data from the Large Eddy Simulations have been compared with the homogeneous model and a methodology is proposed to tackle the heat flux miscalculation due to the numerical implementation. This methodology is not limited to the homogeneous approach, it extends to other approaches such as the thickened perforation model presented in this work which represents enlarged holes based on the size of the cell relative to the hole diameter.

Jury

Franck NICOUD         Université de Montpellier                          Advisor
Antoine DAUPTAIN    CERFACS                                                 Co Advisor
Pascal BRUEL           Université de Pau des Pays de l’Adour     Referee
Marc-Paul ERRERA  ONERA                                                      Referee
Bruno KOOBUS        Université de Montpellier                            Member
Eric SERRE              Ecole Centrale de Marseille                        Member