Design and Analysis of Crown Profile of Fan Rotor Blade Roots for Gas Turbines

The present work is aimed at reducing the stresses developed at the fillet region of the fan disk through crowning of the dovetail flanks of blade roots. The crowning was done along the flank (in-plane crowning) and across the flank (out-of-plane crowning) of the blade root and their influence on the fillet and flank stresses was studied independently, for varying crown heights. A generalized blade root and disk model was analyzed by the finite element method using ANSYS WorkBench 14.5 as a tool, by varying the crown height in different combinations. It was found that out-of-plane crowning of the blade flank is more effective in reducing the stresses at the fillet than in-plane crowning. The final optimization study will include the influence of 3-D crowning, combining the cumulative influence of in-plane and out-of-plane crowning, as well as the realistic gas bending and vibratory forces on actual 3-D airfoils.