At present, it is a common practice to expose engine components to main annulus air temperatures exceeding the thermal material limit in order to increase the overall engine performance and to minimize the engine specific fuel consumption. To prevent overheating of the materials and thus the reduction of component life, an internal flow system is required to cool and protect the critical engine parts. Previous studies have shown that the insertion of a deflector plate in turbine cavities leads to a more effective use of reduced cooling air, since the coolant is fed more effectively into the disk boundary layer. This paper describes a flexible design parameterization of an engine representative turbine stator well geometry with stationary deflector plate and its implementation within an automated design optimization process using automatic meshing and steady-state computational fluid dynamics (CFD). Special attention and effort is turned to the flexibility of the parameterization method in order to reduce the number of design variables to a minimum on the one hand, but increasing the design space flexibility and generality on the other. Finally, the optimized design is evaluated using a previously validated conjugate heat transfer method (by coupling a finite element analysis (FEA) to CFD) and compared against both the nonoptimized deflector design and a reference baseline design without a deflector plate.

In the most evolved designs, it is common practice to expose engine components to main annulus air temperatures exceeding the thermal material limit in order to increase the overall performance and to minimize the engine-specific fuel consumption (SFC). To prevent overheating of the materials and thus the reduction of the component life, an internal flow system is required to cool the critical engine parts and to protect them. This paper shows a practical application and extension of the methodology developed during the five-year research program, main annulus gas path interaction (MAGPI). Extensive use was made of finite element analysis (FEA (solids)) and computational fluid dynamics (CFD (fluid)) modeling techniques to understand the thermomechanical behavior of a dedicated turbine stator well cavity rig, due to the interaction of cooling air supply with the main annulus. Previous work based on the same rig showed difficulties in matching predictions to thermocouple measurements near the rim seal gap. In this investigation, two different types of turbine stator well geometries were analyzed, where—in contrast to previous analyses—further use was made of the experimentally measured radial component displacements during hot running in the rig. The structural deflections were applied to the existing models to evaluate the impact inflow interactions and heat transfer. Additionally, to the already evaluated test cases without net ingestion, cases simulating engine deterioration with net ingestion were validated against the available test data, also taking into account cold and hot running seal clearances. 3D CFD simulations were conducted using the commercial solver fluent coupled to the in-house FEA tool SC03 to validate against available test data of the dedicated rig.

Nowadays, it is common practice to expose engine components to air temperatures exceeding the thermal material limit in order to increase the overall engine performance and to minimise the engine specific fuel consumption (SFC). To avoid the overheating of the materials and thus the reduction of the component life, an internal flow system is designed to cool the critical engine parts and to protect them. As the coolant flow is bled from the compressor and not used for the combustion the amount of coolant is aimed to be minimised as much as possible to preserve the overall engine performance. Experiments as well as numerical simulations have shown that with the use of a deflector plate, the cooling flow is fed more directly into the disc boundary layer, allowing more effective use of less cooling air, leading to an improved engine efficiency. In this paper, the benefits of the use of a stationary deflector plate inside a turbine stator well (TSW) are presented. So far unpublished experimental data obtained from tests carried out in a two-stage turbine rig are presented. The main objective of this research has been to produce reliable methods for predicting the effects of geometry changes in this type of engine cavity, with a view to optimising the cooling flows required to maintain component integrity and life. Therefore, a numerical methodology is presented and validated against the experimental data. Steady and unsteady computational fluid dynamics (CFD) calculations of a sector model are used to determine whether fluid side flow distributions and heat transfer can be adequately represented, as well as to expose the limits of these approaches. The main annulus geometry is meshed with a multi-block structured mesh using the in-house code PADRAM. The cavity geometry is meshed once with a multi-block structured mesh using the commercial tool ANSYS ICEM and once with an unstructured mesh using the in-house code PADRAM. The CFD calculations are carried out with the commercial code FLUENT from ANSYS as well as the in-house code HYDRA. Finally, for the cavity with the deflector plate and no net ingestion, the steady state solution of the CFD is coupled to a finite element analysis (FEA) model created in the in-house code SC03 in order to take the conjugate effects into account. With this method the final non-adiabatic flow field inside the cavity as well as the final metal temperatures are obtained, which again are compared against thermocouple measured data in order to evaluate the accuracy of the numerical prediction method.

In the most evolved designs, it is common practice to expose engine components to main annulus air temperatures exceeding the thermal material limit in order to increase the overall performance and to minimise the engine specific fuel consumption (SFC). To prevent overheating of the materials and thus the reduction of the component life, an internal flow system is required to cool the critical engine parts and to protect them. This paper shows a practical application and extension of the methodology developed during the five year research programme MAGPI. Extensive use was made of FEA (solids) and CFD (fluid) modelling techniques to understand the thermo-mechanical behaviour of a dedicated turbine stator well cavity rig, due to the interaction of cooling air supply with the main annulus. Previous work based on the same rig showed difficulties in matching predictions to thermocouple measurements near the rim seal gap. In this investigation, two different types of turbine stator well geometries were analysed, where further use was made of existing measurements of hot running seal clearances in the rig. The structural deflections were applied to the existing models to evaluate the impact in flow interactions and heat transfer. Additionally to the already evaluated test cases without net ingestion, cases simulating engine deterioration with net ingestion were validated against the available test data, also taking into account cold and hot running seal clearances. 3D CFD simulations were conducted using the commercial solver FLUENT coupled to the in-house FEA tool SC03 to validate against available test data of the dedicated rig.