Stress and deformation of rocket gas turbine disc under different loads using finite element modelling

Abstract

Gas turbine discs have numerous applications in the aerospace industry, such as in liquid rocket engines. In this study, the stresses and deformations of a turbine disc were studied. The goal was to highlight the stress and deformation distribution to assist in the design of a disc as well as to demonstrate the importance of using finite element (FE) analysis in simulating an actual design case. Then, to present the real model, a two-dimensional (2D) axisymmetric model for a non-uniform disc was analysed using FE analysis. The stresses and deformations developed as a result of the disc operating conditions at high rotational speeds and thermal gradients were evaluated using two types of heat transfer modes—conduction and convection, taking into consideration the material behaviour at elevated temperatures. The FE model revealed that the weight of the disc should be reduced optimally by using a non-uniform thickness because this results in a huge increase in the applied stresses. The greatest stresses in the disc result from the thermal load caused by conduction, and they are located at the centre of the disc. In addition, an analytical method was used to evaluate and predict the stresses along the disc, and it gave a good estimate of the stress values compared to the FE model. Based on this estimate, a parametric study was conducted for a range of rotational velocities under high temperature loads for a series of disc radii. Finally, it was found that this method can be used for the preliminary design of different turbines.

Keywords

• Rocket turbine
• Turbine disc
• Stress
• Deformation
• Finite element (FE)