Design study of stress and strain concentration in the area of a heat channel of a turbine rotor under the action of mechanical and thermal loads

1. On the simple example of a rotor with a heat channel subjected to axial tension the finite element method has been used to study the dependence of stress and strain concentration factors on the relative depth and relative radius of the channel. Accuracy of the determination has been confirmed by the good agreement of data obtained with classical solutions for this simple case provided in the work of Peterson. 2. A dependence for the strain concentration factor (with material operating in the plastic region) on the radial temperature drop and gradient with a unidimensional temperature field has been obtained. 3. Satisfactory agreement of results for thermal strain concentration factors calculated by the Makhutov approximate equation (with preliminary use of the Barry-Johnson equation) with more accurate calculation by the FEM has been noted. 4. Calculations for an actual rotor with different starting schedules taking account of temperature changes along the radius and axis show that values of strain concentration factor are in the range 3 to 8.