Impact of Multi-Dimensional Thermal and Structural Analyses on Bolted flange in Gas Turbine

Bolted flanges play a vital role in aircraft engines as they join components, transmit loads and serves as dismantling joint. Most of the bolted flanges in aircraft turbine engines experiences high mechanical loads, thermal gradients and impartial air leakage as they experience massive pressure difference. Thermal and stress analyses plays significant role in the design of bolted flange components as they are used to estimate temperature distribution, flange stresses, number of life cycles, snap fit tightness, and displacement of the flange assembly. Currently two dimensional thermal analyses are carried out at most of the compressor flanges as it simplifies modelling with a compromise in accuracy. It reduces lead time in generating temperature& mechanical distributions. On the other hand, three dimensional thermal analyses capture local features of geometry, boundary conditions and predict circumferential variation in temperature distribution but increases the computational and turnaround time. An effort has been made in this paper to compare the temperature distribution and stresses for two dimensional and three dimensional thermal analyses with varying flange leakage (via gap b/w flanges). Subsequently through structural analysis, mechanical stresses are compared based on 2D& 3D thermal results. Results presented in this paper will be helpful for the selection of 2D thermal analysis Vs 3D