Picture 1. Wireframe of the turbine section. The outer diameter is 82 mm.
Picture 2. Deformation due to 110000/min of rotational speed. The amplification factor is set to 20.
Picture 3. Von Mises stress due to 110000/min rotational speed. Plastification is considered but no creep had taken place. The values along the blade-root are uncertain because the fillet-radius is not modeled.
Picture 4. Heat transfer coefficients, calculated with duns (CFD) based on a simplified 3D-model and interpolated to the fe-model
Picture 5. Steady state temperature distribution used for the burst and creep calculations using the above shown heat transfer coefficients.
Picture 6. Equivalent plastification vs. rotational speed. Save operation is possible below 180000/min.
Picture 7. Equivalent plastification at the last converging time-step of the burst calculation at about 215000/min.
Picture 8. Equivalent creep strain in the blade over 100 h of operation at 110000/min. CalculiX provides an interface for user-written subroutines which was used for this calculation.
Picture 9. Equivalent creep strain after 100 h of operation at 110000/min
Picture 10. Frequency diagram of the turbine-blades. Resonances with the vanes can not be avoided. Stress stiffening due to the rotational force and the increase in temperature with the rotational speed is considered.
Picture 11. Modeshape of the first bending mode with five nodal diameters (1F-5ND). This mode could be triggered by the five hollow vanes used in the gas-turbine. For this calculation the cyclic symmetry capabillity of CalculiX was used.
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