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This paper summarizes the work of a five year research program into the heat transfer within cavities adjacent to the main annulus of a gas turbine. The work has been a collaboration between several gas turbine manufacturers, also involving a number of universities working together. The principal objective of the study has been to develop and validate computer modeling methods of the cooling flow distribution and heat transfer management, in the environs of multistage turbine disk rims and blade fixings, with a view to maintaining component and subsystem integrity, while achieving optimum engine performance and minimizing emissions. A fully coupled analysis capability has been developed using combinations of commercially available and in-house computational fluid dynamics (CFD) and finite element (FE) thermomechanical modeling codes. The main objective of the methodology is to help decide on optimum cooling configurations for disk temperature, stress, and life considerations. The new capability also gives us an effective means of validating the method by direct use of disk temperature measurements, where otherwise, additional and difficult to obtain parameters, such as reliable heat flux measurements, would be considered necessary for validation of the use of CFD for convective heat transfer. A two-stage turbine test rig has been developed and improved to provide good quality thermal boundary condition data with which to validate the analysis methods. A cooling flow optimization study has also been performed to support a redesign of the turbine stator well cavity to maximize the effectiveness of cooling air supplied to the disk rim region. The benefits of this design change have also been demonstrated on the rig. A brief description of the test rig facility will be provided together with some insights into the successful completion of the test program. Comparisons will be provided of disk rim cooling performance for a range of cooling flows and geometiy configurations. The new elements of this work are the presentation of additional test data and validation of the automatically coupled analysis method applied to a partially cooled stator well cavity (i.e., including some local gas ingestion) and also the extension of the cavity cooling design optimization study to other new geometries. [ABSTRACT FROM AUTHOR]

Reliable means of predicting heat transfer in cavities adjacent to the main gas path are increasingly being sought by engineers involved in the design of gas turbines. In this pa-per, an interim summary of the results of a five-year research program sponsored by the European Union (EU) and several leading gas turbine manufacturers and universities will be presented. Extensive use is made of computational fluid dynamics (CFD) and fi-nite element (FE) modeling techniques to understand the thermo-mechanical behavior of a turbine stator well cavity, including the interaction of cooling air supply with the main annulus gas. The objective of the study has been to provide a means of optimizing the design of such cavities for maintaining a safe environment for critical parts, such as disc rims and blade fixings, while maximizing the turbine efficiency and minimizing the fuel burn and emissions penalties associated with the secondary airflow system. The modeling methods employed have been validated against data gathered from a dedicated two-stage turbine rig running at engine representative conditions. Extensive measurements are available for a range of flow conditions and alternative cooling arrangements. The analy-sis method has been used to inform a design change, which is also to be tested. Compari-sons are provided between the predictions and measurements of the turbine stator well component temperature. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]