Investigation of power turbine casing thermal environment using one dimensional thermal-fluid network solver

The gas turbine engine operates in high-temperature, instantly changing power demand and various atmospheric conditions. Therefore, turbine inlet temperature and material selection are among the most critical parameters to maintain its integrity and satisfy power output. However, the higher the turbine inlet temperature is, the less operational time is. Thus, cooling the engine components is crucial regarding the durability, integrity, and reliability of both rotating and structural parts and for controlling blade tip clearances. In addition, thermal and secondary air systems design collectively play a key role in the successful case cooling, as they determine the heat load and cooling flow distribution. The first tool of engineers for an initial concept design is a 1D simulation to create a new cooling system. However, this step can be challenging for designers due to the absence of a 1D modeling methodology in the literature. Therefore, this paper aims to present a 1D network modeling methodology for any turbine geometry at the preliminary design stage. In this sense, a test campaign is carried out to obtain the temperature distribution of a generic power turbine casing using thermocouples and pressure sensors. In addition, a 1D thermo-fluid steady-state model is established. The results of the model are validated against test data. Additionally, a sensitivity analysis is performed, which helps to determine critical geometric locations for the base model and to measure how the model is affected by boundary conditions. Furthermore, another casing geometry with a different cooling system is designed to examine temperature distribution variation on the casing by changing the conduction path of components. Finally, comprehensive comparisons of the geometries with advantages and disadvantageous are considered, and the result of the sensitivity analysis is evaluated.