Low Fidelity Turbomachinery Disk Design Studies

Abstract

Turbomachinery disks are highly stressed, heavy components used in virtually all axially configured gas turbines. Historically, simple plane stress models have primarily been used to quickly analyze the thickness profiles of thin compressor disks. The application of a plane stress model to a more complex system including large thermal gradients or composite materials is much less common. This paper will focus on low fidelity design studies of complex disk systems using a plane stress model. The automated design of a thick, high pressure turbine (HPT) disk with a large radial thermal gradient will be explored. This system clearly shows the limitations of a plane stress model. Discussion will focus on ways to identify and account for inaccuracies in the low fidelity turbine disk results. This paper will also explore the use of a low fidelity stress model in a fan disk design study including both isotropic and composite disk materials. This study shows that with proper assumptions, a plane stress model may be used to investigate a wide range of disk loading and geometry configurations in much less time than would be needed with higher fidelity tools. As examples, hardware from the GE E3 HPT and GE90 fan will be investigated using the disk design program T-Axi Disk. With proper assumptions and an understanding of the stress model, complex disk systems can be designed and optimized accurately at a low fidelity level. The time savings from using a low fidelity tool allows the designer to perform design studies that would be much more difficult or expensive using higher fidelity tools.