The paper provides a methodology for the estimation of heat losses in high-pressure turbine stages. Sophisticated aero-thermal analyses require detailed input data in terms of geometry and boundary conditions. Thinking of a turbine design as a continuing process, this data will not be available at an early design stage. On the other hand, in that very stage many decisions are to be taken which have a severe influence on heat losses. The presented estimation method is based on a simple network of heat resistances. For a design process of a future turbine, the heat resistances have to be calibrated using aero-thermal models or measurements of an existing reference turbine. In a first step, the calibrated resistances will be adapted to the new design using scaling laws based on global parameters such as free-stream velocity and temperature or casing thickness. In the course of turbine design, detailed input data will be available allowing for more complex aero-thermal computations. The results can be used to further improve the heat resistances in order to achieve higher accuracy of the heat loss model. The scaling laws for the heat resistances are compared to CFD computations of exemplary cases. In the following, the method is applied to a typical design scenario. Both, a reference case and a future design of a high-pressure stator 1 geometry including casing and two secondary flow cavities are set-up as conjugate heat transfer models. The elaborated model is used to estimate the heat fluxes of the future design based on the reference case. A comparison to the conjugate heat transfer results illustrates the accuracy of the method.

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