Investigation of Heat Transfer and Flow Field Development Around a Low-Pressure Turbine Blade with the Use of Open Source CFD Tools

Abstract

The present paper is focused on numerical investigations of the heat transfer and flow field development around a low pressure turbine blade (T106) with the use of computational fluid dynamics (CFD) tools and methods. The CFD computations were performed with OpenFoam open source CFD software with the use of the Shear Stress Transport (SST) low-Reynolds number turbulence model. At the first part of the present work, the CFD computations were validated in relation to available detailed isothermal experimental measurements and useful conclusions about the accuracy of the modelling approach and the flow field development were derived. At the next stage, additional CFD computations were performed for flow and thermal conditions adapted in order to reflect more closely the low-pressure turbine blade operation. In these CFD computations the interaction between the velocity and thermal boundary layers and their effect on the heat transfer was quantified through the derivation of the distribution of the local Nusselt number on the T106 surface, which was compared in relation to available correlations from open literature. Through the analysis of the CFD results it was possible to identify the regions on the low-pressure turbine surface in which decreased heat transfer performance was presented as a result of the non-optimum flow and thermal field development. Furthermore, through the CFD computations secondary flow effects resulting in operational efficiency decrease were identified. The elimination of these sources of operational decrease is planned to be the main target of future research efforts targeting the development of methodologies for the design of highly efficient turbomachinery components.